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  • 1.
    Ahlström, Christer
    et al.
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Ask, Per
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Rask, Peter
    University Hospital, Örebro, Sweden .
    Karlsson, Jan-Erik
    County Hospital Ryhov, Jönköping, Sweden.
    Nylander, Eva
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Dahlström, Ulf
    Linköping University, Department of Medicine and Care, Cardiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart Centre, Department of Cardiology.
    Hult, Peter
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Assessment of Suspected Aortic Stenosis by Auto Mutual Information Analysis of Murmurs2007In: Engineering in Medicine and Biology Society, 2007. EMBS 2007, 2007, 1945-1948 p.Conference paper (Refereed)
    Abstract [en]

    Mild sclerotic thickening of the aortic valve affects 25% of the population, and the condition causes aortic valve stenosis (AS) in 2% of adults above 65 years. Echocardiography is today the clinical standard for assessing AS. However, a cost effective and uncomplicated technique that can be used for decision support in the primary health care would be of great value. In this study, recorded phonocardiographic signals were analyzed using the first local minimum of the auto mutual information (AMI) function. The AMI method measures the complexity in the sound signal, which is related to the amount of turbulence in the blood flow and thus to the severity of the stenosis. Two previously developed phonocardiographic methods for assessing AS severity were used for comparison, the murmur energy ratio and the sound spectral averaging technique. Twenty-nine patients with suspected AS were examined with Doppler echocardiography. The aortic jet velocity was used as a reference of AS severity, and it was found to correlate with the AMI method, the murmur energy ratio and the sound spectral averaging technique with the correlation coefficient R = 0.82, R = 0.73 and R = 0.76, respectively.

  • 2.
    Ahlström, Christer
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Hult, Peter
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Rask, P
    Karlsson, J-E
    Nylander, Eva
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Dahlström, Ulf
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Cardiology. Östergötlands Läns Landsting, Heart Centre, Department of Cardiology.
    Ask, Per
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Using the intelligent stethoscope for extraction of features for systolic heart murmur classification2006In: World Congress on Medical Physics and Biomedical Engineering WC2006,2006, 2006Conference paper (Other academic)
  • 3.
    Ahlström, Christer
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Hult, Peter
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Schmekel, Birgitta
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Ask, Per
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Automatisk detektering av ronki med icke-linjära metoder2004In: Svenska Läkaresällskapets riksstämma,2004, 2004, 66-66 p.Conference paper (Other academic)
  • 4.
    Ahlström, Christer
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Hult, Peter
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Schmekel, Birgitta
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Ask, Per
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Wheeze detection with nonlinear statespace embedding2004In: International Lung Sound Association,2004, 2004, 38-39 p.Conference paper (Other academic)
  • 5.
    Ahlström, Christer
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Johansson, Anders
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Länne, Toste
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Ask, Per
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    A respiration monitor based on electrocardiographic and photoplethysmographic sensor fusion2004In: IEEE Engineering in Medical and Biological Society,2004, Piscataway, N.J. USA: IEEEEMBS , 2004, 2311- p.Conference paper (Refereed)
  • 6.
    Ahlström, Christer
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Johansson, Anders
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Uhlin, Fredrik
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Nephrology.
    Länne, Toste
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Ask, Per
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Noninvasive investigation of blood pressure changes using the pulse wave transit time: A novel approach in the monitoring of hemodialysis patients2005In: Journal of Artificial Organs, ISSN 1434-7229, E-ISSN 1619-0904, Vol. 8, no 3, 192-197 p.Article in journal (Refereed)
    Abstract [en]

    Severe blood pressure changes are well known in hemodialysis. Detection and prediction of these are important for the well-being of the patient and for optimizing treatment. New noninvasive methods for this purpose are required. The pulse wave transit time technique is an indirect estimation of blood pressure, and our intention is to investigate whether this technique is applicable for hemodialysis treatment. A measurement setup utilizing lower body negative pressure and isometric contraction was used to simulate dialysis-related blood pressure changes in normal test subjects. Systolic blood pressure levels were compared to different pulse wave transit times, including and excluding the cardiac preejection period. Based on the results of these investigations, a pulse wave transit time technique adapted for dialysis treatment was developed and tried out on patients. To determine systolic blood pressure in the normal group, the total pulse wave transit time was found most suitable (including the cardiac preejection period). Correlation coefficients were r = 0.80 ± 0.06 (mean ± SD) overall and r = 0.81 ± 0.16 and r = 0.09 ± 0.62 for the hypotension and hypertension phases, respectively. When applying the adapted technique in dialysis patients, large blood pressure variations could easily be detected when present. Pulse wave transit time is correlated to systolic blood pressure within the acceptable range for a trend-indicating system. The method's applicability for dialysis treatment requires further studies. The results indicate that large sudden pressure drops, like those seen in sudden hypovolemia, can be detected. © The Japanese Society for Artificial Organs 2005.

  • 7.
    Almer, Sven
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Gastroenterology and Hepatology. Östergötlands Läns Landsting, Centre for Medicine, Department of Endocrinology and Gastroenterology UHL.
    Granerus, Göran
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Ström, Magnus
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Gastroenterology and Hepatology. Östergötlands Läns Landsting, Centre for Medicine, Department of Endocrinology and Gastroenterology UHL.
    Olaison, Gunnar
    Bonnet, Joëlle
    Lémann, Marc
    Smedh, Kennet
    Franzén, Lennart
    Bertheau, Philippe
    Cattan, Pierre
    Rain, Jean-Didier
    Modigliani, Robert
    Leukocyte scintigraphy compared to intraoperative small bowel enteroscopy and laparotomy findings in Crohn's disease2007In: Inflammatory Bowel Diseases, ISSN 1078-0998, E-ISSN 1536-4844, Vol. 13, no 2, 164-174 p.Article in journal (Refereed)
    Abstract [en]

    Background: Leukocyte scintigraphy is a noninvasive investigation to assess inflammation. We evaluated the utility of labeled leukocytes to detect small bowel inflammation and disease complications in Crohn's disease and compared it to whole small bowel enteroscopy and laparotomy findings. Methods: Scintigraphy with technetium-99m exametazime-labeled leukocytes was prospectively performed in 48 patients with Crohn's disease a few days before laparotomy, 41 also had an intraoperative small bowel enteroscopy. The same procedures were performed in 8 control patients. Independent grading of scans was compared with the results of enteroscopy and with surgical, histopathologic, and clinical data. Results: In the 8 control patients leukocyte scan, endoscopy, and histopathology were all negative for the small bowel. In patients with Crohn's disease and small bowel inflammation seen at enteroscopy and/or laparotomy (n = 39) the scan was positive in 33. In 8 patients without macroscopic small bowel inflammation, the scan was positive for the small bowel in 3 patients, at histology, 2 of 3 had inflammation. When combining results for patients and controls, the sensitivity of leukocyte scan for macroscopically evident small bowel inflammation was 0.85, specificity 0.81, accuracy 0.84, positive predictive value 0.92, and negative predictive value 0.68. Scintigraphy detected inflammatory lesions not known before laparotomy in 16 of 47 (34%) Crohn's disease patients and showed uptake in 25 of 35 (71 %) bowel strictures. It was diagnostic regarding 4 of 8 abscesses and 9 of 15 fistulas. In 6 patients (13%) lesions first demonstrated by leukocyte scintigraphy were treated during the surgery performed. Conclusions: Leukocyte scintigraphy reliably detects small bowel inflammation in Crohn's disease. It gives additional information on the presence of inflammatory lesions in a fraction of patients planned for surgery. Copyright © 2006 Crohn's & Colitis Foundation of America, Inc.

  • 8. Anfelter, P
    et al.
    Granerus, Göran
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Stenström, Hugo
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Medical Radiology. Östergötlands Läns Landsting, Centre for Medical Imaging, Department of Radiology UHL.
    Eriksson, Per
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Rheumatology. Östergötlands Läns Landsting, Centre for Medicine, Department of Rheumatology in Östergötland.
    Nyström, Fredrik
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Internal Medicine. Östergötlands Läns Landsting, Centre for Medicine, Department of Endocrinology and Gastroenterology UHL.
    The effect of percutaneous dilatation of renal arterial stenosis on captopril renography in hypertension2005In: Blood Pressure, ISSN 0803-7051, E-ISSN 1651-1999, Vol. 14, no 6, 359-365 p.Article in journal (Refereed)
    Abstract [en]

    Background. The clinical effects of percutaneous transluminal renal artery angioplasty (PTRA) in patients with renal vascular stenosis and hypertension is controversial. Methods. We consecutively recruited all 23 patients referred for evaluation of renovascular hypertension that eventually underwent unilateral PTRA, to be investigated with captopril MAG3 renography (CR), both before and after the endovascular procedure. Data were evaluated on an intention-to-treat basis. Results. We found that the relative MAG3 clearance of the stenotic kidney increased (from 29.9 ± 14% to 35.1 ± 14%, p=0.01) and that the creatinine levels fell following the intervention (from 110 ± 19 to 99 ± 17 μmol/l, p=0.0003). Blood pressure levels were also lowered (from 173 ± 32/93 ± 17 to 158 ± 31/86 ± 15 mmHg, p<0.006) while the mean number of anti-hypertensive drugs was unchanged following PTRA (2.9 ± 1.4 before and 2.8 ± 1.3 drugs after the intervention, respectively, p-0.6). Conclusion. This prospective trial showed statistically significant improvements of individual kidney function as measured by CR and blood pressure in subjects with suspected renovascular hypertension treated with PTRA. Although the endovascular procedure was found to be safe, the magniture of the absolute improvements was rather modest. © 2005 Taylor & Francis.

  • 9.
    Arnold, MF
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Voigt, JU
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Kukulski, T
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Wranne, Bengt
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Sutherland, George R
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Cardiology. Östergötlands Läns Landsting, Heart Centre, Department of Cardiology.
    Hatle, Liv
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Editorial: Does atrioventricular ring motion always distinguish constriction from restriction? A Doppler myocardial imaging study2001In: Journal of the American Society of Echocardiography, ISSN 0894-7317, E-ISSN 1097-6795, Vol. 14, no 5, 391-395 p.Article in journal (Other academic)
    Abstract [en]

    Constrictive pericarditis and restrictive cardiomyopathy can be difficult to differentiate on clinical examination. Cardiac ultrasonography is increasingly being used as the noninvasive method of choice for confirming the specific morphologic and hemodynamic abnormalities associated with either condition. Interrogation of atrioventricular valve plane motion by Doppler myocardial imaging (DMI) has been suggested as a valuable new approach that can help differentiate one from the other. We report the color DMI, pulsed DMI, and strain rate findings in 2 cases of constrictive pericarditis in which consideration of the annular motion pattern alone would not have allowed such differentiation.

  • 10. Aronsson, B
    et al.
    Perk, J
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology.
    Norlén, S
    Hedbäck, Bo
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Cardiology. Östergötlands Läns Landsting, Heart Centre, Department of Cardiology.
    Resuming domestic activities after myocardial infarction: a study in female patients2000In: Scandinavian Journal of Occupational Therapy, ISSN 1103-8128, E-ISSN 1651-2014, Vol. 7, 39-44 p.Article in journal (Refereed)
  • 11.
    Ask, Per
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Brandberg, Joakim
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Janerot-Sjöberg, Birgitta
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Karlsson, Matts
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Loyd, Dan
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Wranne, Bengt
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Assessment of heart valve function with echocardiography1997In: World Congress on Medical Physics and Biomedical Engineering,1997, 1997, 394-394 p.Conference paper (Refereed)
  • 12.
    Ask, Per
    et al.
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    ENGVALL, J
    Loyd, Dan
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Wranne, Bengt
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    THEORETICAL AND EXPERIMENTAL-ANALYSIS OF AORTIC COARCTATION1989In: IMAGES OF THE TWENTY-FIRST CENTURY, PTS 1-6, 1989, Vol. 11, 103-103 p.Conference paper (Refereed)
    Abstract [en]

    Aortic coarctation, which could severely influence the haemodynamic conditions of the body, is discussed. A theory has been developed which relates the pressure drop over the coarctation to the flow. This theory indicates that the pressure drop across the actual coarctation is related to the flow squared. For the collateral flow the expected pressure drop is either linearly or quadratically related to the flow. Model experiments and patient data support the present theoretical model

  • 13.
    Ask, Per
    et al.
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Hult, Peter
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, Faculty of Arts and Sciences.
    Fjallbrant, T
    Wranne, Bengt
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Bioacoustic techniques is applicable to primary health care2001In: PROCEEDINGS OF THE 23RD ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY, VOLS 1-4: BUILDING NEW BRIDGES AT THE FRONTIERS OF ENGINEERING AND MEDICINE, 2001, Vol. 23, 1911-1914 p.Conference paper (Refereed)
    Abstract [en]

    The stethoscope has been used diagnostically for nearly two hundred years to assess the heart function. We can envision the intelligent stethoscope which combines the advantages of the traditional instrument with advanced functionality for analysis of the signal and other information support. The bioacoustic technique is basically simple and robust and fits therefore into a scenario where investigations are performed in a distributed health care system as in primary health care or even home health care. We have focused on detection of respiratory sounds and third heart sounds. The later is performed with a new wavelet technique which makes it possible to automatically detect and identify the sounds and possibly relate them to myocardial insufficiency.

  • 14.
    Ask, Per
    et al.
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Loyd, Dan
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Wranne, Bengt
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Regurgitant flow through heart valves: a hydraulic model applicable to ultrasound Doppler measurements.1986In: Medical and Biological Engineering and Computing, ISSN 0140-0118, E-ISSN 1741-0444, Vol. 24, no 6, 643-646 p.Article in journal (Refereed)
  • 15.
    Ask, Per
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Ressner, Marcus
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Janerot-Sjöberg, Birgitta
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Jansson, Tomas
    Lunds universitet .
    Jurkonis, Rytis
    Kaunas University of Technology, Lithuania .
    Kvikliene, Adriana
    Kaunas University of Technology, Lithuania .
    Hoff, Lars
    Fac of Sience and Engineering, Vestfold University, Horten, Norge .
    Simulation of ultrasound contrast bubble response and the non-linear ultrasound field - combining with in vitro experiments2003In: New England Doppler Conference,2003, 2003Conference paper (Refereed)
  • 16. Barclay, Susan A
    et al.
    Eidenvall, Lars
    Karlsson, Matts
    Andersson, Gunnar
    Xiong, Changsheng
    Ask, Per
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Loyd, Dan
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Wranne, Bengt
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    The shape of the proximal isovelocity surface area varies with regurgitant orifice size and distance from orifice: computer simulation and model experiments with color M-mode technique.1993In: Journal of the American Society of Echocardiography, ISSN 0894-7317, E-ISSN 1097-6795, Vol. 6, no 4, 433-445 p.Article in journal (Refereed)
    Abstract [en]

    The hemispheric proximal isovelocity surface area method for quantification of mitral regurgitant flow (i.e., Qc = 2 pi r2v), where 2 pi r2 is the surface area and v is the velocity at radius r, was investigated as distance from the orifice was increased. Computer simulations and steady flow model experiments were performed for orifices of 4, 6, and 8 mm. Flow rates derived from the centerline velocity and hemispheric assumption were compared with true flow rates. Proximal isovelocity surface area shape varied as distance from each orifice was increased and could only be approximated from the hemispheric equation when a certain distance was exceeded: > 7, > 10, and > 12 mm for the 4, 6, and 8 mm orifices, respectively. Prediction of relative error showed that the best radial zone at which to make measurements was 5 to 9, 6 to 14 and 7 to 17 mm for the 4, 6, and 8 mm orifices, respectively. Although effects of a nonhemispheric shape could be compensated for by use of a correction factor, a radius of 8 to 9 mm can be recommended without the use of a correction factor over all orifices studied if a deviation in calculated as compared with true flow of 15% is considered acceptable. These measurements therefore have implications for the technique in clinical practice.

  • 17. Bech Hanssen, Odd
    et al.
    Wranne, Bengt
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Ask, Per
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Loyd, Dan
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Caidahl, Kenneth
    The net pressure gradients after pressure recovery can be predicted by Doppler in aortic bileaflet prostheses.2001In: American Society of Echocardiography,2001, 2001Conference paper (Refereed)
  • 18. Bech-Hansen, Odd
    et al.
    Caidahl, Kenneth
    Wallentin, Ingemar
    Ask, Per
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Wranne, Bengt
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Assessment of effective orifice area of prosthetic aortic valves with Doppler echocardiography: An in vivo and in vitro study2001In: Journal of Thoracic and Cardiovascular Surgery, ISSN 0022-5223, E-ISSN 1097-685X, Vol. 122, no 2, 287-295 p.Article in journal (Refereed)
    Abstract [en]

    Objectives: We sought to evaluate the Doppler assessment of effective orifice area in aortic prosthetic valves. The effective orifice area is a less flow-dependent parameter than Doppler gradients that is used to assess prosthetic valve function. However, in vivo reference values show a pronounced spread of effective orifice area and smaller orifices than expected compared with the geometric area. Methods: Using Doppler echocardiography, we studied patients who received a bileaflet St Jude Medical valve (n = 75, St Jude Medical, Inc, St Paul, Minn) or a tilting disc Omnicarbon valve (n = 46, Medical CV, Incorporated, Inver Grove Heights, Minn). The prosthetic valves were also investigated in vitro in a steady flow model with Doppler and catheter measurements in the different orifices. The effective orifice area was calculated according to the continuity equation. Results: In vivo, there was a wide distribution with the coefficient of variation (SD/mean ╫ 100%) for different valve sizes ranging from 21% to 39% in the St Jude Medical valve and from 25% to 33% in the Omnicarbon valve. The differences between geometric orifice area and effective orifice area in vitro were 1.26 ▒ 0.41 cm2 for St Jude Medical and 1.17 ▒ 0.38 cm2 for Omnicarbon valves. The overall effective orifice areas and peak catheter gradients were similar: 1.35 ▒ 0.37 cm2 and 25.9 ▒ 16.1 mm Hg for St Jude Medical and 1.46 ▒ 0.49 cm2 and 24.6 ▒ 17.7 mm Hg for Omnicarbon. However, in St Jude Medical valves, more pressure was recovered downstream, 11.6 ▒ 6.3 mm Hg versus 3.4 ▒ 1.6 mm Hg in Omnicarbon valves (P = .0001). Conclusions: In the patients, we found a pronounced spread of effective orifice areas, which can be explained by measurement errors or true biologic variations. The in vitro effective orifice area was small compared with the geometric orifice area, and we suspect that nonuniformity in the spatial velocity profile causes underestimation. The St Jude Medical and Omnicarbon valves showed similar peak catheter gradients and effective orifice areas in vitro, but more pressure was recovered in the St Jude Medical valve. The effective orifice area can therefore be misleading in the assessment of prosthetic valve performance when bileaflet and tilting disc valves are compared.

  • 19. Bech-Hanssen, O
    et al.
    Caidahl, K
    Wallentin, I
    Brandberg, J
    Wranne, Bengt
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Ask, Per
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Aortic prosthetic valve design and size: relation to Doppler echocardiographic findings and pressure recovery- an in vitro study.2000In: Journal of the American Society of Echocardiography, ISSN 0894-7317, E-ISSN 1097-6795, Vol. 13, no 1, 39-50 p.Article in journal (Refereed)
    Abstract [en]

    The extent to which Doppler echocardiography information can be used in the assessment of prosthesis hemodynamic performance is still controversial. The goals of our study were to assess the importance of valve design and size both on Doppler echocardiography findings and on pressure recovery in a fluid mechanics model. We performed Doppler and catheter measurements in the different orifices of the bileaflet St Jude (central and side orifices), the monoleaflet Omnicarbon (major and minor orifices), and the stented Biocor porcine prosthesis. Net pressure gradients were predicted from Doppler flow velocities, assuming either independence or dependence of valve size. The peak Doppler estimated gradients (mean +/- SD for sizes 21 to 27) were 21 +/- 10.3 mm Hg for St Jude, 18 +/- 9.3 mm Hg for Omnicarbon, and 37 +/- 14.5 mm Hg for Biocor (P <.05 for St Jude and Omnicarbon vs Biocor). The pressure recovery (proportion of peak catheter pressure) was 53% +/- 8.6% for central-St Jude, 29% +/- 8. 9% for side-St Jude, 20% +/- 5.6% for major-Omnicarbon, 23% +/- 7.4% for minor-Omnicarbon, and 18% +/- 3.6% for Biocor (P <.05 for central-St Jude and side-St Jude vs Omnicarbon and Biocor). Valve sizes (x) significantly influenced pressure recovery (y in percentage) (central-St Jude: y = 3.7x - 35.9, r = 0.88, P =.0001; major-Omnicarbon: y = 2.1x - 30.3, r = 0.85, P =.0001). By assuming dependence of valve size, Doppler was able to predict net pressure gradients in St Jude with a mean difference between net catheter and Doppler-predicted gradient of -3.8 +/- 2.5 mm Hg. In conclusion, prosthetic valve design and size influence the degree of pressure recovery, making Doppler gradients potentially misleading in both the assessment of hemodynamic performance and the comparison of one design with another. The preliminary results indicate that net gradient can be predicted from Doppler gradients.

  • 20. Bendz, H
    et al.
    Granerus, Göran
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Volkmann, R
    Methods for determination of renal function - what's on offer today?2002In: Läkartidningen, ISSN 0023-7205, E-ISSN 1652-7518, Vol. 99, 3851-3856 p.Article in journal (Other academic)
  • 21.
    Bergdahl, Björn
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care. Östergötlands Läns Landsting, Heart Centre, Department of Cardiology.
    Eintrei, Christina
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Anaesthesiology. Östergötlands Läns Landsting, Anaesthesiology and Surgical Centre, Department of Intensive Care UHL.
    Fyrenius, Anna
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology.
    Hultman, Per
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Molecular and Immunological Pathology. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pathology and Clinical Genetics.
    Theodorsson, Elvar
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Division of clinical chemistry. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Chemistry.
    Läkarutbildningen i Linköpings förnyas. Problembaserat lärande, basvetenskap och folkhälsa förstärks2005In: Läkartidningen, ISSN 0023-7205, E-ISSN 1652-7518, Vol. 102, no 38, 2654-2658 p.Article in journal (Other academic)
  • 22.
    Bergdahl, Björn
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care. Östergötlands Läns Landsting, Heart Centre, Department of Cardiology.
    Fyrenius, Anna
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology.
    Persson, Anne-Christine
    Linköping University, Faculty of Health Sciences.
    EDIT-projekti. PBL: n verkkoskenaariot haastavat opiskelijat ajattelemaan2006In: Ongelmapaperustaisen oppomisen verkko / [ed] Timo Portimojärvi, Tampere: Timo portimojärvi , 2006, -196 p.Chapter in book (Other academic)
    Abstract [fi]

      Kirjassa yhdistyy kaksi runsaasti huomiota saanutta oppimisen, opiskelun ja opetuksen näkökulmaa - välillä yhdessä välillä erikseen. Ongelmaperustainen oppiminen on jo vakiintunut useissa oppilaitoksissa, ja verkko-opiskelu lisääntyy ja kehittyy joustavan opiskelun muotona. Kirja on ensimmäinen suomalainen ongelmaperustaisen oppimisen ja verkko-opiskelun yhdistämiseen keskittyvä kirja.

  • 23.
    Bergdahl, Björn
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Cardiology. Östergötlands Läns Landsting, Heart Centre, Department of Cardiology.
    Fyrenius, Anna
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology.
    Persson, Anne-Christine
    Problembaserat lärande på webben utmanar studenternas tänkande2004In: Läkartidningen, ISSN 0023-7205, E-ISSN 1652-7518, Vol. 101, 3236-3239 p.Article in journal (Other academic)
  • 24.
    Bergström, Anders
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Cardiology. Östergötlands Läns Landsting, Heart Centre, Department of Cardiology.
    Andersson, B
    Edner, M
    Nylander, Eva
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Persson, H
    Dahlström, Ulf
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Cardiology. Östergötlands Läns Landsting, Heart Centre, Department of Cardiology.
    Effect of carvedilol on diastolic function in patients with diastolic heart failure and preserved systolic function. Results of the Swedish Doppler-echocardiographic study (SWEDIC)2004In: European Journal of Heart Failure, ISSN 1388-9842, E-ISSN 1879-0844, Vol. 6, no 4, 453-461 p.Article in journal (Refereed)
    Abstract [en]

    Aim: The purpose of this study was to investigate the effects of carvedilol on diastolic function (DF) in heart failure patients with preserved left ventricular (LV) systolic function and abnormal DF. Patients and Methods: We randomised 113 patients with diastolic heart failure (DHF) (symptomatic, with normal systolic LV function and abnormal DF) into a double blind multi-centre study. The patients received either carvedilol or matching placebo in addition to conventional treatment. After uptitration, treatment was continued for 6 months. Two-dimensional and Doppler echocardiography were used for quantification of LV function at baseline and at follow-up. Four different DF variables were evaluated by Doppler echocardiography: mitral flow E:A ratio, deceleration time (DT), isovolumic relaxation time (IVRT) and the ratio of systolic/diastolic pulmonary venous flow velocity (pv-S/D). Primary endpoint was change in the integrated quantitative assessment of all four variables during the study. Results: Ninety-seven patients completed the study. A mitral flow pattern reflecting a relaxation abnormality was recorded in 95 patients. There was no effect on the primary endpoint, although a trend towards a better effect in carvedilol treated patients was noticed in patients with heart rates above 71 beats per minute. At the end of the study, there was a statistically significant improvement in E:A ratio in patients treated with carvedilol (0.72 to 0.83) vs. placebo (0.71 to 0.76), P<0.05. Conclusions: Treatment with carvedilol resulted in a significant improvement in E:A ratio in patients with heart failure due to a LV relaxation abnormality. E:A ratio was found to be the most useful variable to identify diastolic dysfunction in this patient population. This effect was observed particularly in patients with higher heart rates at baseline. © 2004 European Society of Cardiology.

  • 25.
    Bjarnegård, Niclas
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology.
    Bengtsson, C
    Sturfelt, G
    Nived, O
    Brodszki, J
    Länne, Toste
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care. Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Increased aortic pulse wave velocity in middle ages women with systemic lupou erythematosus2004In: 14th meeting of hypertension,2004, 2004Conference paper (Other academic)
  • 26.
    Bjarnegård, Niclas
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology.
    Bengtsson, C
    Sturfelt, G
    Nived, O
    Brodszki, J
    Länne, Toste
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Ökad central puls¨vågshastighet hos medelålders kvinnor med systemic lupus erythematosus2004In: Svenska Läkaresällskapets Riksstämma,2004, 2004Conference paper (Other academic)
  • 27. Blomqvist, Kjell
    et al.
    Örtoft, Kjell
    Johansson, Åke
    Ascione, Salvatore
    Nylander, Eva
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Åkerlind, Ingemar
    Diagnostik och behandling av hjärtsvikt i primärvården.2000In: Läkartidningen, ISSN 0023-7205, E-ISSN 1652-7518, Vol. 97, 159-162 p.Article in journal (Other (popular science, discussion, etc.))
  • 28.
    Blomstrand, P
    et al.
    Klin fys Jönköping.
    Björklund, P-G
    Klin fys Jönköping.
    Karlsson, J-K
    Med klin Jönköping.
    Engvall, Jan
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Telemedicin möjliggör bättre omhändertagande av patienter2002In: Läkartidningen, ISSN 0023-7205, E-ISSN 1652-7518, Vol. 99, 1704-1707 p.Article in journal (Other academic)
  • 29.
    Blomstrand, Peter
    Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Echocardiographic methods for assessment of coronary artery disease1995Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Upright bicycle exercise echocardiography with digital image acquisition in seated position during exercise and in recumbent position before and immediately after exercise was performed in 66 men, one month after an episode of unstable coronary arte1y disease. It was difficult to obtain images of adequate quality during exercise but new or worsening of wall motion abnormalities not seen in recumbent position after exercise were detected at peak-exercise in patients with good image quality. Therefore, image acquisition seated at peak bicycle exercise and in the recumbent position immediately after exercise are of complementary value.

    Bicycle exercise echocardiography and 201-Tl myocardial perfusion scintigraphy SPECT were compared in 65 men after an episode of unstable coronary artery disease. Reversible abnormalities were seen in 55 patients with cchocardiography and in 43 patients with 201-Tl scintigraphy {p<O.OS). The segmental agreement between the methods was 58%. The additional value of exercise echocardiography and 201-Tl SPECT to exercise test was greatest in patients with one-vessel disease as detected by coronary angiography.

    The hemodynamic alterations induced by dobutamine stress testing were investigated using Doppler-echocardiography and venous occlusion plethysmography in 11 healthy women and 18 female patients. The healthy subjects received a lower peak-dose of dobutamine, 22±7.5 j.lg kg-I miu-1 compared with 33±9.7 j.lg kg- I min-I administered to the patients (p<O.Ol). The increase in hemt rate during dobutamine infusion was significantly greater in the subjects, +68%, compared with the patients, +49%, {p<O.OS). Corresponding figures for changes in systolic blood flow velocity in the left ventricular outflow tracts were +82% versus +50% (p<0.01), cardiac output +93% versus +60% (p<0.05), total peripheral vascular resistance -49% versus -44% and leg peripheral vascular resistance -32% versus -26% (not significant) in subjects and patients respectively. The hemodynamic alterations were age and dose dependant in the subjects. Mean systolic blood pressure for the two groups was unchanged but one subject and four patients developed hypotension (decrease in systolic blood pressure >10 mm Hg). One patient in the hypotension group developed a paradoxical vagal reaction with bradycardia at peak-dose and two patients had a very low increase in cardiac output (12%). The fomth patient with hypotension did not differ in change in cardiac output compared to the other patients. Despite a more pronounced decrease in total peripheral vascular resistance in these four patients compared with other patients, there was no difference in leg peripheral vascular resistance between the groups. The disparity between the pattern of total to legperipheral vascular resistance in patients with hypotension might reflect a baroreceptor mediated compensatmy increase in vasoconstrictor tone of muscle vessels not matched in other vascular territories.

    Echocardiographic M-mode recordings of mitral annulus motion were compared with Doppler registrations of mitral and pulmonary venous flow velocities in 38 patients with heart failure (NYHA ll-IU) after myocm·dial infarction. Patients with an increased atlial component of annulus motion in absolute (a :::::5.1 mm, n::::l9) or relative terms (a/T >57%, n::::l2) had a higher miti·allate to early flow velocity ratio and pulmonmy venoussystolic to diastolic filling ratio (p<O.OS), which is associated with prolonged left ventricular relaxation. Patients with an increased afT ratio also had a more pronounced left ventricular systolic dysfunction compared with others {p<0.01). There was a significant con-dation between afT ratio and AlE ratio (r=0.61, p<0.001) but the information contained in the two indices was not identical.

  • 30. Bolger, A F
    et al.
    Eidenvall, L
    Ask, Per
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Loyd, Dan
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Wranne, Bengt
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Understanding continuous-wave Doppler signal intensity as a measure of regurgitant severity.1997In: Journal of the American Society of Echocardiography, ISSN 0894-7317, E-ISSN 1097-6795, Vol. 10, no 6, 613-622 p.Article in journal (Refereed)
    Abstract [en]

    Continuous-wave Doppler signal intensity is commonly expected to reflect the severity of mitral regurgitation. Physical principles predict that alignment of the imaging beam, flow velocity, and turbulence can also be important or even dominant determinants of continuous-wave Doppler signal intensity. The reliability of tracking regurgitant severity with continuous-wave Doppler signal intensity was assessed in vitro with varying volume, velocity, turbulence, and beam alignment. The conditions wherein continuous-wave Doppler signal intensity increased with regurgitant volume were specific but poorly predictable combinations of orifice size, flow volume, and perfect beam alignment. Under other conditions flow velocity and turbulence effects dominated, and continuous-wave Doppler signal intensity did not reflect changing regurgitant volume. Continuous-wave Doppler signal intensity-based impressions of regurgitant severity may be unreliable and even misleading under some circumstances.

  • 31. Bolger, Ann
    et al.
    Eidenvall, Lars
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Ask, Per
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Loyd, Dan
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Wranne, Bengt
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Understanding continuous wave Doppler signal intensity as a measure of regurgitant severity1997In: Journal of the American Society of Echocardiography, ISSN 0894-7317, E-ISSN 1097-6795, Vol. 10, 613-622 p.Article in journal (Refereed)
  • 32.
    Bolger, Ann F
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Eidenvall, Lars
    Ask, Per
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Loyd, Dan
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Wranne, Bengt
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    THE MULTIPLE DETERMINANTS OF CONTINUOUS WAVE SIGNAL INTENSITY1992In: Circulation, ISSN 0009-7322, E-ISSN 1524-4539, Vol. 86, no 4, SArticle in journal (Refereed)
  • 33.
    Bolger, Ann F
    et al.
    Linköping University, Department of Medicine and Care, Center for Medical Image Science and Visualization. Linköping University, Faculty of Health Sciences.
    Heiberg, Einar
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Department of Medicine and Care, Center for Medical Image Science and Visualization. Linköping University, Faculty of Health Sciences.
    Karlsson, Matts
    Linköping University, Department of Biomedical Engineering. Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Wigström, Lars
    Linköping University, Department of Medicine and Care, Center for Medical Image Science and Visualization. Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Engvall, Jan
    Linköping University, Department of Medicine and Care, Center for Medical Image Science and Visualization. Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Sigfridsson, Andreas
    Linköping University, Department of Medicine and Care, Center for Medical Image Science and Visualization. Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Ebbers, Tino
    Linköping University, Department of Medicine and Care, Center for Medical Image Science and Visualization. Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Escobar Kvitting, John-Peder
    Linköping University, Department of Medicine and Care, Center for Medical Image Science and Visualization. Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Carlhäll, Carljohan
    Linköping University, Department of Medicine and Care, Center for Medical Image Science and Visualization. Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Wranne, Bengt
    Linköping University, Department of Medicine and Care, Center for Medical Image Science and Visualization. Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Transit of blood flow through thehuman left ventricle mapped by cardiovascular magnetic resonance2007In: Journal of Cardiovascular Magnetic Resonance, ISSN 1097-6647, E-ISSN 1532-429X, Vol. 9, no 5, 741-747 p.Article in journal (Refereed)
    Abstract [en]

    BACKGROUND:

    The transit of blood through the beating heart is a basic aspect of cardiovascular physiology which remains incompletely studied. Quantification of the components of multidirectional flow in the normal left ventricle (LV) is lacking, making it difficult to put the changes observed with LV dysfunction and cardiac surgery into context.

    METHODS:

    Three dimensional, three directional, time resolved magnetic resonance phase-contrast velocity mapping was performed at 1.5 Tesla in 17 normal subjects, 6 female, aged 44+/-14 years (mean+/-SD). We visualized and measured the relative volumes of LV flow components and the diastolic changes in inflowing kinetic energy (KE). Of total diastolic inflow volume, 44+/-11% followed a direct, albeit curved route to systolic ejection (videos 1 and 2), in contrast to 11% in a subject with mildly dilated cardiomyopathy (DCM), who was included for preliminary comparison (video 3). In normals, 16+/-8% of the KE of inflow was conserved to the end of diastole, compared with 5% in the DCM patient. Blood following the direct route lost or transferred less of its KE during diastole than blood that was retained until the next beat (1.6+/-1.0 millijoules vs 8.2+/-1.9 millijoules, p<0.05); whereas, in the DCM patient, the reduction in KE of retained inflow was 18-fold greater than that of the blood tracing the direct route.

    CONCLUSION:

    Multidimensional flow mapping can measure the paths, compartmentalization and kinetic energy changes of blood flowing into the LV, demonstrating differences of KE loss between compartments, and potentially between the flows in normal and dilated left ventricles.

  • 34. Bothe, W
    et al.
    Carlhäll, Carljohan
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Nguyen, TC
    Itoh, A
    Timek, TA
    Lai, D
    Ingels, NB
    Miller, DC
    Early mitral leaflet opening during acute ischemic mitral regurgitation.2007In: Fourth Biennial Meeting of the Society for Heart Valve Disease,2007, 2007Conference paper (Other academic)
  • 35. Bothe, W
    et al.
    Nguyen, TC
    Ennis, DB
    Carlhäll, Carljohan
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Itoh, A
    Lai, DT
    Ingels, NB
    Miller, DC
    Regional and temporal insights into mitral orifice area during acute ischemic mitral regurgitation2007In: 21st Annual Meeting of the European Association for Cardio-Thoracic Surgery,2007, 2007Conference paper (Other academic)
    Abstract [en]

      

  • 36.
    Brandberg, Joakim
    Linköping University, Department of Biomedical Engineering. Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Department of Mechanical Engineering. Linköping University, Faculty of Health Sciences.
    On cardiac flow quantification with ultrasound colour doppler2000Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis deals with the estimation of blood flow in the heart and larger vessels where control-volume methods are applied using ultrasound Doppler technique. In particular two control-volume techniques were investigated: The proximal isovelocity surface area method, (PISA) and the Surface Integration of Velocity Vectors method, (SIVV).

    For PISA, computational fluid dynamics, (CFD) was used for non-stationary flow and non-planar circular geometries where special emphasis was given to the influence from the angle of the valvular leaflets on the proximal surface area. The CFD results were compared with ultrasound measurements, in an in-vitro model with controlled geometry and flow characteristics. Three different valvular geometries were used: planar, reversed cone and funnel. In these idealised CFD and experimental models it was found that there is support to use the hemispherical PISA approach for the geometries investigated provided that the flow is not to high in the reversed cone and funnel case. At high flows the actual proximal geometry should be used instead of an entire hemisphere.

    A hydraulic pulsatile model was used in developing a platform with in-house software where the SIVV flows automatically may be calculated from a digitally stored raw data. An antialiasing algorithm was developed to allow for measurement of aliased data in order to increase the dynamic velocity range. The antialiasing algorithm was found to improve the estimation of SIVV flow.

    The influence on the flow estimate was investigated with respect to the number of scan-planes using a numerical model and in-vitro and in-vivo model experiments. It was found that a minimum of two scan-planes are needed when flow conditions and geometry is close to circular, otherwise the recommendation is four scan-planes.

    A steady state and a pulsatile model was used to evaluate accuracy of the SIVV method more extensively in vitro. SIVV was found to be accurate and repeatable with a slight underestimation in the pulsatile model but within the ±10% range. In the steady state model a strong correlation was found between SIVV and timed flow. However, since discrepancies in regression equations were obtained for different tube diameters further investigation of steady state flows in vessels of small diameter are needed.

    An in-vivo model was designed to study the possibility to use the SIVV method to measure cardiac output in a paediatric model in haemodynamically unstable subjects and to investigate what measurement site to use. Epicardial measurements were performed on a series of piglets using two different temporal resolutions. SJVV accuracy was compared with ultrasound transit time flow and was found to be in parity or better than current invasive methods. Inter- and lntraobserver variability was found to be low.

    List of papers
    1. Non-stationary flow through non-planar circular constrictions: application to mitral valve disease
    Open this publication in new window or tab >>Non-stationary flow through non-planar circular constrictions: application to mitral valve disease
    Show others...
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    Quantification of valvular malfunctions by means of noninvasive methods is presently far from perfect. Since valvular regurgitation is common, a simple and reliable method for quantitative assessment is desired. In this paper the proximal isovelocity surface area method, (PISA) was studied. Numerical simulations for non-stationary flow and non-planar circular geometries were compared with ultrasound measurements in an invitro model with the same geometry and similar flow characteristics. Three different valvular geometries were used: planar, reversed cone and funnel. In the numerical simulation special emphasis was given to the influence from the angle of the valvular leaflets on the proximal surface area. We found both numerically and experimentally that there is support to use the hemispherical velocity profile assumption for the geometries investigated except for the funnel case. Here the actual geometry at the funnel inlet should be considered instead of the half-sphere approximation.

    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-89303 (URN)
    Available from: 2013-02-25 Created: 2013-02-25 Last updated: 2016-03-14
    2. Increased accuracy of echocardiographic measurement of flow using automated spherical integration of multiple plane velocity vectors
    Open this publication in new window or tab >>Increased accuracy of echocardiographic measurement of flow using automated spherical integration of multiple plane velocity vectors
    1999 (English)In: Ultrasound in Medicine and Biology, ISSN 0301-5629, E-ISSN 1879-291X, Vol. 25, no 2, 249-257 p.Article in journal (Refereed) Published
    Abstract [en]

    The calculation of blood flow in the heart by surface integration of velocity vectors (SIVV) using Doppler ultrasound is independent of the angle. Flow is normally calculated from velocity in a spherical thick shell with its center located at the ultrasound transducer. In a numerical simulation, we have shown that the ratio between minor and major axes of an elliptic flow area substantially influences the accuracy of the estimation of flow in a single scan plane. The accuracy of flow measurements by SIVV can be improved by calculating the mean of the values from more than one scan plane. We have produced an automated computer program that includes an antialiasing procedure. We confirmed an improvement of flow measurements in a pulsatile hydraulic flow model, the 95% confidence interval for single estimations being reduced from 20% to 10% (p < 0.05) using the newly developed software. We think that the SIVV method has important implications for clinical transthoracic echocardiography.

    National Category
    Medical Laboratory and Measurements Technologies
    Identifiers
    urn:nbn:se:liu:diva-67263 (URN)10.1016/S0301-5629(98)00159-8 (DOI)10320314 (PubMedID)
    Available from: 2011-04-06 Created: 2011-04-06 Last updated: 2017-12-11
    3. How many planes are necessary for accurate cardiac output measurement using surface integration of velocity vectors (SIVV) in the left ventricular outflow tract? Pediatric application
    Open this publication in new window or tab >>How many planes are necessary for accurate cardiac output measurement using surface integration of velocity vectors (SIVV) in the left ventricular outflow tract? Pediatric application
    Show others...
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    Flow measurements with surface integration of velocity vectors, (SIVV) is a three dimensional approach where velocities measured by colour Doppler from several two-dimensional imaging planes are gathered and flow is automatically calculated. With SIVV no assumptions regarding the Doppler insonation angle, area changes and flow profile are necessary, thus avoiding such errors. Numerical simulations have shown that an elliptic area less than 1:2 in major minor axis relation needs at least two equidistant (preferably four) planes for accurate measurements. The purpose of this study was to evaluate this finding in a controlled in vitro environment and in high quality in vivo observations. A Plexiglass® pulsatile flow model was used where the outflow tract allows for insertion of an artificial valve. A total of 12 images were acquired with an increment of 15o at three flow rates (0.9- 3.0 1/min). A series of piglets (13.5-17 kg) were stemotomized, and a 5MHz phased array transthoracic probe placed at the apex with the beam directed towards the left ventricular outflow tract, (LVOT) simulating the transoesophageal transgastric or transthoracic apical view. Epicardial images were acquired in 4 planes (45o increments). Ten high quality sequences at different cardiac output levels (0.9 - 2.1 1/min) were selected and compared to ultrasound transit time (TT) cardiac output measurement. The results show that for the in-vitro case, at least two planes were necessary for measurements with an error of <10%. In-vivo, four planes were required for errors of <20%. Our study confirms the theoretical assumption that at least two planes are preferable to obtain accurate flow measurements from colour Doppler data.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-89306 (URN)
    Available from: 2013-02-25 Created: 2013-02-25 Last updated: 2013-02-25
    4. Doppler flow measurement using surface integration of velocity vectors (Sivv): in vitro validation
    Open this publication in new window or tab >>Doppler flow measurement using surface integration of velocity vectors (Sivv): in vitro validation
    Show others...
    2000 (English)In: Ultrasound in Medicine and Biology, ISSN 0301-5629, E-ISSN 1879-291X, Vol. 26, no 2, 255-262 p.Article in journal (Refereed) Published
    Abstract [en]

    Blood flow measurement using an improved surface integration of velocity vectors (SIVV) technique was tested in in vitro phantoms. SIVV was compared with true flow (12–116 mL/s) in a steady-state model using two angles of insonation (45° and 60°) and two vessel sizes (internal diameter = 11 and 19 mm). Repeatability of the method was tested at various flow rates for each angle of insonation and vessel. In a univentricular pulsatile model, SIVV flow measured at the mitral inlet was compared to true flow (29–61 mL/s). Correlation was excellent for the 19-mm vessel (r2= 0.99). There was a systematic bias but close limits of agreement (mean ± 2 SD = −24.1% ± 7.6% at 45 °; +16.4% ± 11.0% at 60 °). Using the 11-mm vessel, a quadratic relationship was demonstrated between between SIVV and true flow (r2 = 0.98–0.99), regardless of the angle of insonation. In the pulsatile system, good agreement and correlation were shown (r2 = 0.94, mean ± 2 SD = −4.7 ± 10.1%). The coefficients of variation for repeated SIVV measurements ranged from 0.9% to 10.3%. This method demonstrates precision and repeatability, and is potentially useful for clinical measurements.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-29740 (URN)10.1016/S0301-5629(99)00136-2 (DOI)15139 (Local ID)15139 (Archive number)15139 (OAI)
    Available from: 2009-10-09 Created: 2009-10-09 Last updated: 2017-12-13
    5. Pediatric cardiac output measurement using surface integration of velocity vectors: an in vivo validation study
    Open this publication in new window or tab >>Pediatric cardiac output measurement using surface integration of velocity vectors: an in vivo validation study
    Show others...
    2000 (English)In: Critical Care Medicine, ISSN 0090-3493, E-ISSN 1530-0293, Vol. 28, no 11, 3664-3671 p.Article in journal (Refereed) Published
    Abstract [en]

    Objective: To test the accuracy and reproducibility of systemic cardiac output (CO) measurements using surface integration of velocity vectors (SIVV) in a pediatric animal model with hemodynamic instability and to compare SIVV with traditional pulsed-wave Doppler measurements.

    Design: Prospective, comparative study.

    Setting: Animal research laboratory at a university medical center.

    Subjects: Eight piglets weighing 10-15 kg.

    Interventions: Hemodynamic instability was induced by using inhalation of isoflurane and infusions of colloid and dobutamine.

    Measurements: SIVV CO was measured at the left ventricular outflow tract, the aortic valve, and ascending aorta. Transit time CO was used as the reference standard.

    Results: There was good agreement between SIVV and transit time CO. At high frame rates, the mean difference ± 2 sd between the two methods was 0.01 ± 0.27 L/min for measurements at the left ventricular outflow tract, 0.08 ± 0.26 L/min for the ascending aorta, and 0.06 ± 0.25 L/min for the aortic valve. At low frame rates, measurements were 0.06 ± 0.25, 0.19 ± 0.32, and 0.14 ± 0.30 L/min for the left ventricular outflow tract, ascending aorta, and aortic valve, respectively. There were no differences between the three sites at high frame rates. Agreement between pulsed-wave Doppler and transit time CO was poorer, with a mean difference ± 2 sd of 0.09 ± 0.93 L/min. Repeated SIVV measurements taken at a period of relative hemodynamic stability differed by a mean difference ±2 sd of 0.01 ± 0.22 L/min, with a coefficient of variation = 7.6%. Intraobserver coefficients of variation were 5.7%, 4.9%, and 4.1% at the left ventricular outflow tract, ascending aorta, and aortic valve, respectively. Interobserver variability was also small, with a coefficient of variation = 8.5%.

    Conclusions: SIVV is an accurate and reproducible flow measurement technique. It is a considerable improvement over currently used methods and is applicable to pediatric critical care.

    National Category
    Medical Laboratory and Measurements Technologies
    Identifiers
    urn:nbn:se:liu:diva-62969 (URN)11098971 (PubMedID)
    Available from: 2010-12-08 Created: 2010-12-08 Last updated: 2017-12-11
  • 37.
    Brandberg, Joakim
    et al.
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    Chew, M.
    Anaesthesia & Intensive Care and Cardiothoracic Surgery, The Institute for Experimental Clinical Research, Skejby Sygehys, Aarhus, Denmark.
    Bjærum, S.
    Department of Physiology and Biomedical Engineering, Trondheim University, Norway.
    Torp, Hans
    Department of Physiology and Biomedical Engineering, Trondheim University, Norway.
    Ask, Per
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    Janerot Sjöberg, Birgitta
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    How many planes are necessary for accurate cardiac output measurement using surface integration of velocity vectors (SIVV) in the left ventricular outflow tract? Pediatric applicationManuscript (preprint) (Other academic)
    Abstract [en]

    Flow measurements with surface integration of velocity vectors, (SIVV) is a three dimensional approach where velocities measured by colour Doppler from several two-dimensional imaging planes are gathered and flow is automatically calculated. With SIVV no assumptions regarding the Doppler insonation angle, area changes and flow profile are necessary, thus avoiding such errors. Numerical simulations have shown that an elliptic area less than 1:2 in major minor axis relation needs at least two equidistant (preferably four) planes for accurate measurements. The purpose of this study was to evaluate this finding in a controlled in vitro environment and in high quality in vivo observations. A Plexiglass® pulsatile flow model was used where the outflow tract allows for insertion of an artificial valve. A total of 12 images were acquired with an increment of 15o at three flow rates (0.9- 3.0 1/min). A series of piglets (13.5-17 kg) were stemotomized, and a 5MHz phased array transthoracic probe placed at the apex with the beam directed towards the left ventricular outflow tract, (LVOT) simulating the transoesophageal transgastric or transthoracic apical view. Epicardial images were acquired in 4 planes (45o increments). Ten high quality sequences at different cardiac output levels (0.9 - 2.1 1/min) were selected and compared to ultrasound transit time (TT) cardiac output measurement. The results show that for the in-vitro case, at least two planes were necessary for measurements with an error of <10%. In-vivo, four planes were required for errors of <20%. Our study confirms the theoretical assumption that at least two planes are preferable to obtain accurate flow measurements from colour Doppler data.

  • 38.
    Brandberg, Joakim
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Chew, Michelle
    University of Aarhus Denmark.
    Hasenkam, Michael
    Aarhus University Hospital Aarhus, Denmark.
    Ask, Per
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Janerot-Sjöberg, Birgitta
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Cardiac output measurement using ultrasound in a paediatric model: In-vivo validation of the surface integration of velocity vectros (SIVV) technique1999In: Clinical Physiology, ISSN 0144-5979, E-ISSN 1365-2281, Vol. 19, no 3, 198-198 p.Article in journal (Refereed)
  • 39.
    Brandberg, Joakim
    et al.
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    Janerot Sjöberg, Birgitta
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Ask, Per
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    Increased accuracy of echocardiographic measurement of flow using automated spherical integration of multiple plane velocity vectors1999In: Ultrasound in Medicine and Biology, ISSN 0301-5629, E-ISSN 1879-291X, Vol. 25, no 2, 249-257 p.Article in journal (Refereed)
    Abstract [en]

    The calculation of blood flow in the heart by surface integration of velocity vectors (SIVV) using Doppler ultrasound is independent of the angle. Flow is normally calculated from velocity in a spherical thick shell with its center located at the ultrasound transducer. In a numerical simulation, we have shown that the ratio between minor and major axes of an elliptic flow area substantially influences the accuracy of the estimation of flow in a single scan plane. The accuracy of flow measurements by SIVV can be improved by calculating the mean of the values from more than one scan plane. We have produced an automated computer program that includes an antialiasing procedure. We confirmed an improvement of flow measurements in a pulsatile hydraulic flow model, the 95% confidence interval for single estimations being reduced from 20% to 10% (p < 0.05) using the newly developed software. We think that the SIVV method has important implications for clinical transthoracic echocardiography.

  • 40.
    Brandberg, Joakim
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Janerot-Sjöberg, Birgitta
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Wodlin, Peter
    Ask, Per
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Sun, Y
    The SIVV technique for quantifying cardiovascular flows in vivo1996In: Congress of the European Society of Cardiology,1996, 1996Conference paper (Refereed)
  • 41.
    Brandberg, Joakim
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Janerot-Sjöberg, Birgitta
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Wodlin, Peter
    Loyd, Dan
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Ask, Per
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Sun, Y
    In vivo estimation of cardiovascular flows with surface integration of velocity vectors from color Doppler imaging1996In: Annual International Conference of the IEEE Engineering in Medicine and Biology Society,1996, IEEE , 1996Conference paper (Refereed)
  • 42.
    Brandberg, Joakim
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Karlsson, Matts
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Eidenvall, Lars
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Janerot-Sjöberg, Birgitta
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Loyd, Dan
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Wranne, Bengt
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Ask, Per
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Automated calculation of regrgitation from proximal 2D Doppler data1996In: Congress of the European Society of Cardiology,1996, 1996Conference paper (Refereed)
  • 43.
    Brandberg, Joakim
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Karlsson, Matts
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Loyd, Dan
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Wranne, Bengt
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Ask, Per
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Integration of proximal velocities (IPROV) - An improvment of the pisa method for estimation of regurgitant flow.1998In: European Soc for Noninvasive Cardiovascular Dynamics,1998, 1998, 161-161 p.Conference paper (Other academic)
  • 44.
    Brandt, Einar
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Ebbers, Tino
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Wigström, Lars
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Karlsson, Matts
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Automatisk flödeskaraktärisering av tredimensionella vektorfält.2001In: In proceedings of Svenska Mekanikdagarna,2001, 2001, 61-62 p.Conference paper (Refereed)
  • 45.
    Brandt, Einar
    et al.
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Wigström, Lars
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Wranne, Bengt
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Segmentation of echo cardiographic image sequences using spatio-temporal information1999In: Medical Image Computing and Computer-Assisted Intervention – MICCAI’99: Second International Conference, Cambridge, UK, September 19-22, 1999. Proceedings / [ed] Chris Taylor, Alan Colchester, Berlin: Springer, 1999, Vol. 1679, 410-419 p.Chapter in book (Refereed)
    Abstract [en]

    This paper describes a new method for improving border detection in image sequences by including both spatial and temporal information. The method is based on three dimensional quadrature filters for estimating local orientation. A simplification that gives a significant reduction in computational demand is also presented. The border detection framework is combined with a segmentation algorithm based on active contours or ’snakes’, implemented using a new optimization relaxation that can be solved to optimality using dynamical programming. The aim of the study was to compare segmentation performance using gradient based border detection and the proposed border detection algorithm using spatio-temporal information. Evaluation is performed both on a phantom and in-vivo data from five echocardiographic short axis image sequences. It could be concluded that when temporal information was included weak and incomplete boundaries could be found where gradient based border detection failed. Otherwise there was no significant difference in performance between the new proposed method and gradient based border detection.

  • 46. Brodin, Lars-Åke
    et al.
    Janerot Sjöberg, Birgitta
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Förhoppningsfull framtid för ekokardiografin. Utveckling sker inom såväl funktions- perfusionsområdet.2000In: Läkartidningen, ISSN 0023-7205, E-ISSN 1652-7518, Vol. 97, 5302-5309 p.Article in journal (Other academic)
  • 47. Brodszki, J
    et al.
    Länne, Toste
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Marsal, K
    Ley, D
    Impaired vascular growth in late adolescence after intrauterine growth restriction2005In: Circulation, ISSN 0009-7322, E-ISSN 1524-4539, Vol. 111, no 20, 2623-2628 p.Article in journal (Refereed)
    Abstract [en]

    Background - Abnormal blood flow in a fetus small for gestational age indicates true fetal intrauterine growth restriction (IUGR). We tested the hypothesis that IUGR with abnormal fetal blood flow is associated with long-term abnormal vascular morphology and function in adolescence. Methods and Results - In a prospective study, vascular mechanical properties of the common carotid artery (CCA), abdominal aorta , and popliteal artery (PA) were assessed by echo-tracking sonography in 21 adolescents with IUGR and abnormal fetal aortic blood flow and in 23 adolescents with normal fetal growth and normal fetal aortic blood flow. Endothelium-dependent and -independent vasodilatation of the brachial artery was measured by high-resolution ultrasound. After adjustment for body surface area and sex, the IUGR group had significantly smaller end-diastolic vessel diameters than the referents in the abdominal aorta and PA (mean difference, 1.7 mm [95% CI, 0.62 to 2.74] and 0.6 mm [95% CI, 0.25 to 1.02], respectively) (P=0.003 and P=0.002, respectively), with a similar trend in the CCA (P=0.09). A higher resting heart rate was observed in the IUGR group (P=0.01). No differences were found in stiffness or in endothelium-dependent and -independent vasodilatation between the 2 groups. Conclusions - IUGR caused by placental insufficiency appears to be associated with impaired vascular growth persisting into young adulthood in both men and women. The smaller aortic dimensions and the higher resting heart rate seen in adolescents with previous IUGR may be of importance for future cardiovascular health. © 2005 American Heart Association, Inc.

  • 48.
    Börjesson, Mats
    et al.
    Sahlgrenska University Hospital.
    Dellborg, Mikael
    Sahlgrenska University Hospital.
    Nylander, Eva
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Letter: Sports medicine update2006In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 16, 376-377 p.Article in journal (Other academic)
  • 49.
    Börjesson, Mats
    et al.
    smärtcentrum o medicinkliniken Sahlgrenska, Göteborg.
    Nylander, Eva
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Plötslig hjärtdöd hos idorttare beror oftast på odiagnostiserad hjärtsjukdom2005In: Läkartidningen, ISSN 0023-7205, E-ISSN 1652-7518, Vol. 102, 560-563 p.Article in journal (Other academic)
  • 50.
    Carlhäll, Carljohan
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Department of Medicine and Care, Center for Medical Image Science and Visualization. Linköping University, Faculty of Health Sciences.
    Annular dynamics of the human heart: novel echocardiographic approaches to assess ventricular function2004Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The complex myocardial fiber architecture of the left ventricle (LV) enables long-axis motion (annular excursion), short-axis motion and also a small torsional deformation throughout the cardiac cycle. The contribution of the long-axis motion has proven to be important in generating ventricular filling and emptying, and the analysis of annular excursion has become a well established diagnostic tool for the assessment of ventricular function. Cardiac motion can be accurately described with modem non-invasive imaging teclmiques, and this is important ground for deeper understanding and more reliable diagnosis of cardiovascular disease. The focus of this thesis was to provide new insights into cardiac pump function using variables originating from the annular excursion and dynamic changes in shape, applying both established and novel echocardiographic imaging approaches.

    The traditional method of evaluating systolic ventricular fimction according to the total annular excursion overestimates the excursion amplitude in relation to true systolic fimction. A novel method presented here, measurement of the systolic annular excursion, more accurately reflects the timing of true systole, and was applied both in patients with heart disease and in healthy subjects. To date, the form of asynchronous myocardial motion called postsystolic shortening (PSS) has mainly been observed in the setting of myocardial ischemia. The significance of PSS in hypertensive heart disease remains incompletely described. We found that a subgroup of hypertensive patients with PSS along the LV long-axis had signs of more severe cardiac involvement unrelated to the level of blood pressure. Endurance trained subjects showed a larger LV long-axis motion as compared to strength trained and untrained controls. Mitral annular (MA) excursion correlated strongly to LV stroke volume, end-diastolic volume and maximal oxygen consumption per body weight, but weakly to LV ejection fraction. These findings provide further evidence of the importance of annular excursion to normal cardiac performance. In order to assess the contribution of MA excursion and shape dynamics to total LV volume change in humans, a novel 4-dimensional transesophageal echocardiography teclmique was developed. The excursion of the annulus accounted for an important portion (19±3%) of the total LV filling and emptying in healthy human subjects. Furthermore, our findings elucidate an atrial influence on MA physiology in humans, as well as a sphincter-like action of the MA. These temporal changes may facilitate ventricular filling by annular expansion during early and mid diastole, and aid competent valve closure during the marked decrease in annular area during late diastole and early systole.

    List of papers
    1. A novel method to assess systolic ventricular function using atrioventricular plane displacement: a study in young healthy males and patients with heart disease
    Open this publication in new window or tab >>A novel method to assess systolic ventricular function using atrioventricular plane displacement: a study in young healthy males and patients with heart disease
    2004 (English)In: Clinical Physiology and Functional Imaging, ISSN 1475-0961, E-ISSN 1475-097X, Vol. 24, no 4, 190-195 p.Article in journal (Refereed) Published
    Abstract [en]

    Analysis of atrioventricular plane displacement (AVPD) is a well established method for assessment of both systolic and diastolic ventricular function. For several years, AVPD has been a clinical tool and there are many current, as well as potential, areas of application. However, clinical work has shown that the traditional method for evaluation of systolic ventricular function, called total AVPD, does not temporally reflect true systole. Systolic AVPD is a new approach for measuring AVPD to assess ventricular systolic function. We wished to apply this new model in healthy subjects and in patients with different common heart diseases. Twenty-eight young healthy males and 30 patients (aortic stenosis, left sided regurgitant lesions, postmyocardial infarction) were enrolled. AVPD was obtained at the four standard sites by M-mode. Total AVPD was measured in the conventional way and systolic AVPD by identifying true systole, by means of mitral- and aortic valve closure respectively. Ventricular volumes were calculated according to biplane Simpson's rule. The systolic AVPD measurements were significantly lower than the total measurements, at both atrioventricular planes in all groups (P<0·001). This discrepancy was greater at the mitral than at the tricuspid annulus in the patients 24·2% vs. 15·5% (P<0·001), but did not differ in the healthy subjects. At the mitral annulus, this discrepancy also seemed to be more pronounced in the patients than in the healthy subjects 24·2% vs. 10·7%. When assessing ventricular systolic function by AVPD, the conventional method overestimates the amplitude in relation to true systolic function in both patients with heart disease and in young healthy males. Thus, there are uncertainties regarding earlier estimations of AVPD in terms of expression of systolic function and regarding previously presented reference values. We recommend the proposed methodology.

    Keyword
    echocardiography, overestimation, reference values, systolic performance, ventricular long axis motion
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-23404 (URN)10.1111/j.1475-097X.2004.00547.x (DOI)2846 (Local ID)2846 (Archive number)2846 (OAI)
    Available from: 2009-10-07 Created: 2009-10-07 Last updated: 2017-12-13Bibliographically approved
    2. Is left ventricular postsystolic long-axis shortening a marker for severity of hypertensive heart disease?
    Open this publication in new window or tab >>Is left ventricular postsystolic long-axis shortening a marker for severity of hypertensive heart disease?
    2003 (English)In: American Journal of Cardiology, ISSN 0002-9149, E-ISSN 1879-1913, Vol. 91, no 12, 1490-1493 p.Article in journal (Refereed) Published
    Abstract [en]

    No abstract available.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-26833 (URN)10.1016/S0002-9149(03)00407-7 (DOI)11448 (Local ID)11448 (Archive number)11448 (OAI)
    Available from: 2009-10-08 Created: 2009-10-08 Last updated: 2017-12-13Bibliographically approved
    3. Atrioventricular plane displacement correlates closely to circulatory dimensions but not to ejection fraction in normal young subjects
    Open this publication in new window or tab >>Atrioventricular plane displacement correlates closely to circulatory dimensions but not to ejection fraction in normal young subjects
    2001 (English)In: Clinical Physiology, ISSN 0144-5979, E-ISSN 1365-2281, Vol. 21, no 5, 621-628 p.Article in journal (Refereed) Published
    Abstract [en]

    Aims Mitral atrioventricular plane displacement (AVPD) provides information about left ventricular systolic function. M-mode of systolic annulus amplitude or tissue Doppler imaging of systolic annulus velocity are the current methods of evaluating AVPD. A correlation to ejection fraction (EF) has been demonstrated in patients with coronary artery disease and left ventricular dysfunction. Our aim was (i) to investigate the mitral AVPD of normal subjects with different physical work capacities and (ii) to further evaluate AVPD as an index of left ventricular systolic function.

    Methods and results Twenty-eight healthy men mean age 28 years (20–39) were included: endurance trained (ET) (n=10), strength trained (ST) (n=9) and untrained (UT) (n=9). The systolic AVPD was recorded at four sites, septal, lateral, anterior and posterior, using M-mode. Left ventricular volumes were calculated according to Simpson’s rule. Systolic AVPD was higher in endurance trained, 16·9 ± 1·5 mm, as compared with both strength trained, 13 ± 1·6 (P<0·001) and untrained, 14 ± 1·6 (P<0·001). Left ventricular systolic AVPD correlated strongly with end-diastolic volume (r=0·82), stroke volume (r=0·80) and maximal oxygen consumption per body weight (r=0·72). The correlation between AVPD and EF was poor (r=0·22).

    Conclusion  In the subjects studied, with a range of normal cardiac dimensions, AVPD correlated to stroke volume, end-diastolic volume and maximal oxygen consumption per body weight, but not to EF. On theoretical grounds, it also seems reasonable that a dimension like AVPD is related to other cardiac dimensions and volumes, rather than to a fraction, like EF. AVPD is one parameter that is useful for evaluation of left ventricular systolic function but is not interchangeable with other measurements such as EF.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-26832 (URN)10.1046/j.1365-2281.2001.00356.x (DOI)11447 (Local ID)11447 (Archive number)11447 (OAI)
    Available from: 2009-10-08 Created: 2009-10-08 Last updated: 2017-12-13Bibliographically approved
    4. Contribution of mitral annular excursion and shape dynamics to total left ventricular volume change
    Open this publication in new window or tab >>Contribution of mitral annular excursion and shape dynamics to total left ventricular volume change
    Show others...
    2004 (English)In: American Journal of Physiology. Heart and Circulatory Physiology, ISSN 0363-6135, E-ISSN 1522-1539, Vol. 287, no 4, H1836-H1841 p.Article in journal (Refereed) Published
    Abstract [en]

    The mitral annulus (MA) has a complex shape and motion, and its excursion has been correlated to left ventricular (LV) function. During the cardiac cycle the annulus’ excursion encompasses a volume that is part of the total LV volume change during both filling and emptying. Our objective was to evaluate the contribution of MA excursion and shape variation to total LV volume change. Nine healthy subjects aged 56 ± 11 (means ± SD) years underwent transesophageal echocardiography (TEE). The MA was outlined in all time frames, and a four-dimensional (4-D) Fourier series was fitted to the MA coordinates (3-D+time) and divided into segments. The annular excursion volume (AEV) was calculated based on the temporally integrated product of the segments’ area and their incremental excursion. The 3-D LV volumes were calculated by tracing the endocardial border in six coaxial planes. The AEV (10 ± 2 ml) represented 19 ± 3% of the total LV stroke volume (52 ± 12 ml). The AEV correlated strongly with LV stroke volume (r = 0.73; P < 0.05). Peak MA area occurred during middiastole, and 91 ± 7% of reduction in area from peak to minimum occurred before the onset of LV systole. The excursion of the MA accounts for an important portion of the total LV filling and emptying in humans. These data suggest an atriogenic influence on MA physiology and also a sphincter-like action of the MA that may facilitate ventricular filling and aid competent valve closure. This 4-D TEE method is the first to allow noninvasive measurement of AEV and may be used to investigate the impact of physiological and pathological conditions on this important aspect of LV performance.

    Keyword
    annular physiology, ventricular long axis function, echocardiography, three dimension, four dimension
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-24050 (URN)10.1152/ajpheart.00103.2004 (DOI)3608 (Local ID)3608 (Archive number)3608 (OAI)
    Available from: 2009-10-07 Created: 2009-10-07 Last updated: 2017-12-13Bibliographically approved
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