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  • 1.
    Ahle, Margareta
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Radiology in Linköping.
    Ringertz, Hans G.
    Department of Radiology, Stanford University Medical Center, Stanford, USA; Division of Diagnostic Radiology, Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden.
    Rubesova, Erika
    Department of Radiology, Lucile Packard Children’s Hospital, Stanford University Medical Center, Stanford, USA.
    The role of imaging in the management of necrotising enterocolitis: a multispecialist survey and a review of the literature2018In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 28, no 9, p. 3621-3631Article in journal (Refereed)
    Abstract [en]

    Objectives

    To investigate current practices and perceptions of imaging in necrotising enterocolitis (NEC) according to involved specialists, put them in the context of current literature, and identify needs for further investigation.

    Methods

    Two hundred two neonatologists, paediatric surgeons, and radiologists answered a web-based questionnaire about imaging in NEC at their hospitals. The results were descriptively analysed, using proportion estimates with 95% confidence intervals.

    Results

    There was over 90% agreement on the value of imaging for confirmation of the diagnosis, surveillance, and guidance in decisions on surgery as well as on abdominal radiography as the first-choice modality and the most important radiographic signs. More variation was observed regarding some indications for surgery and the use of some ultrasonographic signs. Fifty-eight per cent stated that ultrasound was used for NEC at their hospital. Examination frequency, often once daily or more but with considerable variations, and projections used in AR were usually decided individually rather than according to fixed schedules. Predicting the need of surgery was regarded more important than formal staging.

    Conclusion

    Despite great agreement on the purposes of imaging in NEC and the most important radiographic signs of the disease, there was considerable diversity in routines, especially regarding examination frequency and the use of ultrasound. Apart from continuing validation of ultrasound, important objectives for future studies include definition of the supplementary roles of both imaging modalities in relation to other diagnostic parameters and evaluation of various imaging routines in relation to timing of surgery, complications, and mortality rate.

  • 2. Axelsson, B
    et al.
    Bodén, K
    Fransson, Sven Göran
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Radiology. Östergötlands Läns Landsting, Heart Centre, Department of Cardiology.
    Hansson, I B
    Persliden, Jan
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Radio Physics.
    Witt, Hans
    A comparison of analogue and digital techniques in upper gastrointestinal examinations: absorbed dose and diagnostic quality of the images.2000In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 10, p. 1351-1354Article in journal (Refereed)
  • 3.
    Dahlqvist Leinhard, Olof
    et al.
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences.
    Dahlström, Nils
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Radiology in Linköping.
    Kihlberg, Johan
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Radiology in Linköping.
    Sandström, Per
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Surgery.
    Brismar, Torkel
    Department of Clinical Science, Intervention and Technology at Karolinska Institutet, Division of Medical Imaging and Technology, Karolinska University Hospital in Huddinge, Stockholm, Sweden.
    Smedby, Örjan
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Radiology in Linköping.
    Lundberg, Peter
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics. Östergötlands Läns Landsting, Center for Diagnostics, Department of Radiology in Linköping.
    Quantifying differences in hepatic uptake of the liver specific contrast agents Gd-EOB-DTPA and Gd-BOPTA: a pilot study2012In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 22, no 3, p. 642-653Article in journal (Refereed)
    Abstract [en]

    Objectives   To develop and evaluate a procedure for quantifying the hepatocyte-specific uptake of Gd-BOPTA and Gd-EOB-DTPA using dynamic contrast-enhanced (DCE) MRI. Methods   Ten healthy volunteers were prospectively recruited and 21 patients with suspected hepatobiliary disease were retrospectively evaluated. All subjects were examined with DCE-MRI using 0.025 mmol/kg of Gd-EOB-DTPA. The healthy volunteers underwent an additional examination using 0.05 mmol/kg of Gd-BOPTA. The signal intensities (SI) of liver and spleen parenchyma were obtained from unenhanced and enhanced acquisitions. Using pharmacokinetic models of the liver and spleen, and an SI rescaling procedure, a hepatic uptake rate, K Hep, estimate was derived. The K Hep values for Gd-EOB-DTPA were then studied in relation to those for Gd-BOPTA and to a clinical classification of the patient’s hepatobiliary dysfunction. Results   K Hep estimated using Gd-EOB-DTPA showed a significant Pearson correlation with K Hep estimated using Gd-BOPTA (r = 0.64; P < 0.05) in healthy subjects. Patients with impaired hepatobiliary function had significantly lower K Hep than patients with normal hepatobiliary function (K Hep = 0.09 ± 0.05 min-1 versus K Hep = 0.24 ± 0.10 min−1; P < 0.01). Conclusions   A new procedure for quantifying the hepatocyte-specific uptake of T 1-enhancing contrast agent was demonstrated and used to show that impaired hepatobiliary function severely influences the hepatic uptake of Gd-EOB-DTPA. Key Points   • The liver uptake of contrast agents may be measured with standard clinical MRI.Calculation of liver contrast agent uptake is improved by considering splenic uptake.Liver function affects the uptake of the liver-specific contrast agent Gd-EOB-DTPA.Hepatic uptake of two contrast agents (Gd-EOB-DTPA, Gd-BOPTA) is correlated in healthy individuals.This method can be useful for determining liver function, e.g. before hepatic surgery

  • 4.
    Gaillard, Francois
    et al.
    Paris Descartes University, France.
    Pavlov, Patrik
    Linköping University.
    Tissier, Anne-Marie
    Paris Descartes University, France.
    Harache, Benoit
    Paris Descartes University, France.
    Eladari, Dominique
    Paris Descartes University, France; INSERM, France.
    Timsit, Marc-Olivier
    Paris Descartes University, France.
    Fournier, Catherine
    Paris Descartes University, France.
    Leon, Carine
    Paris Descartes University, France.
    Hignette, Chantal
    Paris Descartes University, France.
    Friedlander, Gerard
    Paris Descartes University, France; INSERM, France.
    Correas, Jean-Michel
    Paris Descartes University, France.
    Weinmann, Pierre
    Paris Descartes University, France.
    Mejean, Arnaud
    Paris Descartes University, France.
    Houillier, Pascal
    Paris Descartes University, France; CNRS, France.
    Legendre, Christophe
    Paris Descartes University, France.
    Courbebaisse, Marie
    Paris Descartes University, France; INSERM, France.
    Use of computed tomography assessed kidney length to predict split renal GFR in living kidney donors2017In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 27, no 2, p. 651-659Article in journal (Refereed)
    Abstract [en]

    Screening of living kidney donors may require scintigraphy to split glomerular filtration rate (GFR). To determine the usefulness of computed tomography (CT) to split GFR, we compared scintigraphy-split GFR to CT-split GFR. We evaluated CT-split GFR as a screening test to detect scintigraphy-split GFR lower than 40 mL/min/1.73 m(2)/kidney. This was a monocentric retrospective study on 346 potential living donors who had GFR measurement, renal scintigraphy, and CT. We predicted GFR for each kidney by splitting GFR using the following formula: Volume-split GFR for a given kidney = measured GFR*[volume of this kidney/(volume of this kidney + volume of the opposite kidney)]. The same formula was used for length-split GFR. We compared length- and volume-split GFR to scintigraphy-split GFR at donation and with a 4-year follow-up. A better correlation was observed between length-split GFR and scintigraphy-split GFR (r = 0.92) than between volume-split GFR and scintigraphy-split GFR (r = 0.89). A length-split GFR threshold of 45 mL/min/1.73 m(2)/kidney had a sensitivity of 100 % and a specificity of 75 % to detect scintigraphy-split GFR less than 40 mL/min/1.73 m(2)/kidney. Both techniques with their respective thresholds detected living donors with similar eGFR evolution during follow-up. Length-split GFR can be used to detect patients requiring scintigraphy. aEuro cent Excellent correlation between kidney length and scintigraphy predicted GFR aEuro cent Kidney length screening detects all donors with GFR lower than 40 mL/min/1.73 m (2) aEuro cent Kidney length screening can replace scintigraphy screening.

  • 5. Geijer, H
    et al.
    Persliden, Jan
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Radiation Physics. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics.
    Radiation exposure and patient experience during percutaneous coronary intervention using radial and femoral artery access2004In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 14, no 9, p. 1674-1680Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to evaluate radiation dose and patient discomfort/pain in radial artery access vs femoral artery access in percutaneous coronary intervention (PCI). Dose-area product (DAP) was measured non-randomised for 114 procedures using femoral access and for 55 using radial access. The patients also responded to a questionnaire concerning discomfort and pain during and after the procedure. The mean DAP was 69.8 Gy cm2 using femoral access and 70.5 Gy cm2 using radial access. Separating the access site from confounding factors with a multiple regression, there was a 13% reduction in DAP when using radial access (p=0.038). Procedure times did not differ (p=0.81). Bed confinement was much longer in the femoral access group (448 vs 76 min, p=0.000). With femoral access, there was a significantly higher patient grading for chest (p=0.001) and back pain (p=0.003) during the procedure and for access site (p=0.000) and back pain (p=0.000) after the procedure. Thirty-two femoral access patients (28%) were given morphine-type analgesics in the post-procedure period compared to three radial access patients (5%, P=0.001). DAP does not increase when using radial instead of femoral access and the patients grade discomfort and pain much lower when using radial access. Radial access is thus beneficial to use.

  • 6.
    Geijer, Håkan
    et al.
    Department of Radiology, Örebro Medical Centre Hospital, Örebro, Sweden.
    Beckman, Karl-Wilhelm
    Department of Medical Physics, Örebro Medical Centre Hospital, Örebro, Sweden.
    Andersson, Tony
    Department of Radiology, Örebro Medical Centre Hospital, Örebro, Sweden.
    Persliden, Jan
    Department of Medical Physics, Örebro Medical Centre Hospital, Örebro, Sweden.
    Radiation dose optimization in coronary angiography and percutaneous coronary intervention (PCI): II. Clinical evaluation2002In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 12, no 11, p. 2813-2819Article in journal (Refereed)
    Abstract [en]

    In a previous part of this study, the fluoroscopy dose rate was reduced in a cardiac catheterization laboratory. The objectives of the present study were to evaluate the effects in a clinical population undergoing percutaneous coronary intervention (PCI) of the dose-reducing measures detailed previously. Kerma area-product (KAP) values were first recorded for 154 patients undergoing PCI. Then, the fluoroscopy KAP rate was reduced from 44 to 16 mGy cm2/s by increasing filtration and reducing the image intensifier dose request. After this optimization, KAP was recorded for another 138 PCI procedures. After adjustment for differing proportions of combined procedures (coronary angiography+PCI), the total KAP was reduced to 67% of the original value with a 95% confidence interval from 57 to 78%, statistically significant. The mean total KAP values were 93.6 Gy cm2 before and 69.1 Gy cm2 after optimization. The KAP for digital acquisition did not change significantly. It is possible to make a large dose reduction in PCI by reducing the fluoroscopy dose rate. This dose reduction is beneficial for both patients and staff.

  • 7.
    Geijer, Håkan
    et al.
    Department of Radiology, Örebro Medical Centre Hospital, Örebro, Sweden.
    Beckman, Karl-Wilhelm
    Department of Medical Physics, Örebro Medical Centre Hospital, Örebro, Sweden.
    Andersson, Torbjörn
    Department of Radiology, Örebro Medical Centre Hospital, Örebro, Sweden.
    Persliden, Jan
    Department of Medical Physics, Örebro Medical Centre Hospital, Örebro, Sweden.
    Image quality vs radiation dose for a flat-panel amorphous silicon detector: a phantom study2001In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 11, no 9, p. 1704-1709Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to investigate the image quality for a flat-panel amorphous silicon detector at various radiation dose settings and to compare the results with storage phosphor plates and a screen-film system. A CDRAD 2.0 contrast-detail phantom was imaged with a flat-panel detector (Philips Medical Systems, Eindhoven, The Netherlands) at three different dose levels with settings for intravenous urography. The same phantom was imaged with storage phosphor plates at a simulated system speed of 200 and a screen-film system with a system speed of 160. Entrance surface doses were recorded for all images. At each setting, three images were read by four independent observers. The flat-panel detector had equal image quality at less than half the radiation dose compared with storage phosphor plates. The difference was even larger when compared with film with the flat-panel detector having equal image quality at approximately one-fifth the dose. The flat-panel detector has a very favourable combination of image quality vs radiation dose compared with storage phosphor plates and screen film.

  • 8.
    Geijer, Håkan
    et al.
    Department of Radiology, Örebro University Hospital, Örebro, Sweden.
    Beckman, Karl-Wilhelm
    Department of Medical Physics, Örebro University Hospital, Örebro, Sweden.
    Andersson, Torbjörn
    Department of Radiology, Örebro University Hospital, Örebro, Sweden.
    Persliden, Jan
    Department of Medical Physics, Örebro University Hospital, Örebro, Sweden.
    Radiation dose optimization in coronary angiography and percutaneous coronary intervention (PCI): I. Experimental studies2002In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 12, no 10, p. 2571-2581Article in journal (Refereed)
    Abstract [en]

    The objectives of this study were to evaluate the influence on image quality and dose to the patient and operator of various equipment settings for percutaneous coronary intervention (PCI), and to optimize the set-up. With an Alderson phantom, different settings, such as projection, protective screens, filtration, image intensifier size and collimation, were evaluated. Kerma-area product (KAP) was recorded as a measure of patient dose and scattered radiation was measured with an ionization chamber. Effective dose for a standardized PCI procedure was measured with thermoluminescent dosimeters inside the phantom. Image quality was evaluated with a contrast-detail phantom. Based on these findings, the equipment set-up was optimized to a low fluoroscopy dose rate with a sufficient image quality. Several operating parameters affected dose, particularly scattered radiation. The optimization reduced the fluoroscopy KAP rate from 44 to 16 mGy cm2/s using 15 cm of acrylic. The effective dose was reduced from 13 to 4.6 mSv for a standardized PCI procedure. Radiation dose to patient and operator in PCI is heavily dependent on both equipment set-up and operating parameters which can be influenced by the operator. With a careful optimization, a large reduction of radiation dose is possible.

  • 9.
    Geijer, Håkan
    et al.
    Department of Radiology, Örebro Medical Centre Hospital, Örebro, Sweden.
    Verdonck, Bert
    Philips Medical Systems, Best, The Netherlands.
    Beckman, Karl-Wilhelm
    Department of Medical Physics, Örebro Medical Centre Hospital, Örebro, Sweden.
    Andersson, Torbjörn
    Department of Radiology, Örebro Medical Centre Hospital, Örebro, Sweden.
    Persliden, Jan
    Department of Medical Physics, Örebro Medical Centre Hospital, Örebro, Sweden.
    Digital Radiography of Scoliosis with a Scanning Method: Radiation Dose Optimization2003In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 13, no 3, p. 543-551Article in journal (Refereed)
    Abstract [en]

    The aim of this study was optimization of the radiation dose–image quality relationship for a digital scanning method of scoliosis radiography. The examination is performed as a digital multi-image translation scan that is reconstructed to a single image in a workstation. Entrance dose was recorded with thermoluminescent dosimeters placed dorsally on an Alderson phantom. At the same time, kerma area product (KAP) values were recorded. A Monte Carlo calculation of effective dose was also made. Image quality was evaluated with a contrast-detail phantom and Visual Grading. The radiation dose was reduced by lowering the image intensifier entrance dose request, adjusting pulse frequency and scan speed, and by raising tube voltage. The calculated effective dose was reduced from 0.15 to 0.05 mSv with reduction of KAP from 1.07 to 0.25 Gy cm2 and entrance dose from 0.90 to 0.21 mGy. The image quality was reduced with the Image Quality Figure going from 52 to 62 and a corresponding reduction in image quality as assessed with Visual Grading. The optimization resulted in a dose reduction to 31% of the original effective dose with an acceptable reduction in image quality considering the intended use of the images for angle measurements.

  • 10.
    Helmrot, Ebba
    et al.
    Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics.
    Pettersson, Håkan
    Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics. Linköping University, Department of Medicine and Care, Radiation Physics. Linköping University, Faculty of Health Sciences.
    Sandborg, Michael
    Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Center for Medical Image Science and Visualization (CMIV). Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics. Linköping University, Faculty of Health Sciences.
    Nilsson Althen, Jonas
    Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics.
    Estimation of the dose to the unborn child at diagnostic X-ray examinations based on data registrerad in RIS/PACS2007In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 17, no 1, p. 205-209Article in journal (Refereed)
    Abstract [en]

    The aim of this work was to determine mean absorbed doses to the unborn child in common conventional X-ray and computed tomography (CT) examinations and to find an approach for estimating foetal dose based on data registered in the Radiological Information System/Picture Archive and Communication System (RIS/PACS). The kerma-area product (KAP) and CT dose index (CTDIvol) in common examinations were registered using a human-shaped female dosimetry phantom. Foetal doses, Df, were measured using thermoluminescent dosimeters placed inside the phantom and compared with calculated values. Measured foetal doses were given in relation to the KAP and the CTDIvol values, respectively. Conversion factor Df/KAP varies between 0.01 and 3.8 mGy/Gycm2, depending on primary beam position, foetus age and beam quality (tube voltage and filtration). Conversion factors Df/CTDIvol are in the range 0.02 – 1.2 mGy/mGy, in which the foetus is outside or within the primary beam. We conclude that dose conversion factors based on KAP or CTDIvol values automatically generated by the RIS/PACS system can be used for rapid estimations of foetal dose for common examination techniques.

  • 11.
    Jackowski, Christian
    et al.
    Universität Zürich, Inst für Rechtsmedizin, Winterthurerstrasse 190/52, CH-8057 Zürich, Switzerland.
    Warntjes, Marcel
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Berge, Johan
    Rättsmedicinalverket, Rättsmedicinska avdelningen, Artillerigatan 12, 587 58 Linköping.
    Bär, Walter
    Universität Zürich, Inst für Rechtsmedizin, Winterthurerstrasse 190/52, CH-8057 Zürich, Switzerland.
    Persson, Anders
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiology. Östergötlands Läns Landsting, Center for Diagnostics, Department of Radiology in Linköping. Linköping University, Faculty of Health Sciences.
    Magnetic resonance imaging goes postmortem: noninvasive detection and assessment of myocardial infarction by postmortem MRI2011In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. Jan;21, no 1, p. 70-78Article in journal (Refereed)
    Abstract [en]

    OBJECTIVE: To investigate the performance of postmortem magnetic resonance imaging (pmMRI) in identification and characterization of lethal myocardial infarction in a non-invasive manner on human corpses.

    MATERIALS AND METHODS: Before forensic autopsy, 20 human forensic corpses were examined on a 1.5-T system for the presence of myocardial infarction. Short axis, transversal and longitudinal long axis images (T1-weighted; T2-weighted; PD-weighted) were acquired in situ. In subsequent autopsy, the section technique was adapted to short axis images. Histological investigations were conducted to confirm autopsy and/or radiological diagnoses.

    RESULTS: Nineteen myocardial lesions were detected and age staged with pmMRI, of which 13 were histologically confirmed (chronic, subacute and acute). Six lesions interpreted as peracute by pmMRI showed no macroscopic or histological finding. Five of the six peracute lesions correlated well to coronary pathology, and one case displayed a severe hypertrophic alteration.

    CONCLUSION: pmMRI reliably demonstrates chronic, subacute and acute myocardial infarction in situ. In peracute cases pmMRI may display ischemic lesions undetectable at autopsy and routine histology. pmMRI has the potential to substantiate autopsy and to counteract the loss of reliable information on causes of death due to the recent disappearance of the clinical autopsy.

  • 12.
    Jansson, Margareta
    et al.
    Department of Radiology, Örebro University Hospital, 701 85 Örebro, Sweden.
    Geijer, Håkan
    Department of Radiology, Örebro University Hospital, 701 85 Örebro, Sweden.
    Persliden, Jan
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medical and Health Sciences, Radiation Physics. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics.
    Andersson, Torbjörn
    Department of Radiology, Örebro University Hospital, 701 85 Örebro, Sweden.
    Reducing dose in urography while maintaining image quality - A comparison of storage phosphor plates and a flat-panel detector2006In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 16, no 1, p. 221-226Article in journal (Refereed)
    Abstract [en]

    The introduction of new flat-panel detector technology often forces us to accept too high dose levels as proposed by the manufacturers. We need a tool to compare the image quality of a new system with the accepted standard. The aim of this study was to obtain a comparable image quality for two systems - storage phosphor plates and a flat-panel system using intravenous urography (IVU) as a clinical model. The image quality figure was calculated using a contrast-detail phantom (CDRAD) for the two evaluated systems. This allowed us to set a dose for the flat-panel system that gave equivalent image quality to the storage phosphor plates. This reduced detector dose was used in an evaluation of clinical images to find out if the dose reduction from the phantom study indeed resulted in images of equal clinical image quality. The image quality was assessed using image criteria of the European guidelines for IVU with visual grading analysis. Equivalent image quality in image pairs was achieved at 30% of the dose. The CDRAD contrast-detail phantom makes it possible to find dose levels that give equal image quality using different imaging systems. © Springer-Verlag 2005.

  • 13.
    Kataria, Bharti
    et al.
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Region Östergötland, Center for Diagnostics, Department of Radiology in Linköping. Linköping University, Faculty of Medicine and Health Sciences.
    Nilsson Althen, Jonas
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Medical radiation physics.
    Smedby, Örjan
    School of Technology and Health (STH), KTH Royal Institute, Stockholm, Sweden.
    Persson, Anders
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Region Östergötland, Center for Diagnostics, Department of Radiology in Linköping.
    Sökjer, Hannibal
    Linköping University, Department of Medical and Health Sciences. Linköping University, Faculty of Medicine and Health Sciences.
    Sandborg, Michael
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Medical radiation physics.
    Assessment of image quality in abdominal CT: potential dose reduction with model-based iterative reconstruction2018In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084Article in journal (Refereed)
    Abstract [en]

    Purpose To estimate potential dose reduction in abdominal CT by visually comparing images reconstructed with filtered back projection (FBP) and strengths of 3 and 5 of a specific MBIR.

    Material and methods A dual-source scanner was used to obtain three data sets each for 50 recruited patients with 30, 70 and 100% tube loads (mean CTDIvol 1.9, 3.4 and 6.2 mGy). Six image criteria were assessed independently by five radiologists. Potential dose reduction was estimated with Visual Grading Regression (VGR).

    Results Comparing 30 and 70% tube load, improved image quality was observed as a significant strong effect of log tube load and reconstruction method with potential dose reduction relative to FBP of 22–47% for MBIR strength 3 (p < 0.001). For MBIR strength 5 no dose reduction was possible for image criteria 1 (liver parenchyma), but dose reduction between 34 and 74% was achieved for other criteria. Interobserver reliability showed agreement of 71–76% (κw 0.201–0.286) and intra-observer reliability of 82–96% (κw 0.525–0.783).

    Conclusion MBIR showed improved image quality compared to FBP with positive correlation between MBIR strength and increasing potential dose reduction for all but one image criterion.

  • 14.
    Norén, Bengt
    et al.
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Radiology in Linköping.
    Forsgren, Mikael Fredrik
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics.
    Dahlqvist Leinhard, Olof
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics.
    Dahlström, Nils
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Radiology in Linköping.
    Kihlberg, Johan
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Radiology in Linköping.
    Romu, Thobias
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Kechagias, Stergios
    Linköping University, Department of Medical and Health Sciences, Internal Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Gastroentorology.
    Almer, Sven
    Linköping University, Department of Clinical and Experimental Medicine, Gastroenterology and Hepatology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Gastroentorology.
    Smedby, Örjan
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Radiology in Linköping.
    Lundberg, Peter
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics. Östergötlands Läns Landsting, Center for Diagnostics, Department of Radiology in Linköping.
    Separation of advanced from mild hepatic fibrosis by quantification of the hepatobiliary uptake of Gd-EOB-DTPA2013In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 23, no 1, p. 174-181Article in journal (Refereed)
    Abstract [en]

    Objectives

    To apply dynamic contrast-enhanced (DCE) MRI on patients presenting with elevated liver enzymes without clinical signs of hepatic decompensation in order to quantitatively compare the hepatocyte-specific uptake of Gd-EOB-DTPA with histopathological fibrosis stage.

    Methods

    A total of 38 patients were prospectively examined using 1.5-T MRI. Data were acquired from regions of interest in the liver and spleen by using time series of single-breath-hold symmetrically sampled two-point Dixon 3D images (non-enhanced, arterial and venous portal phase; 3, 10, 20 and 30 min) following a bolus injection of Gd-EOB-DTPA (0.025 mmol/kg). The signal intensity (SI) values were reconstructed using a phase-sensitive technique and normalised using multiscale adaptive normalising averaging (MANA). Liver-to-spleen contrast ratios (LSC_N) and the contrast uptake rate (KHep) were calculated. Liver biopsy was performed and classified according to the Batts and Ludwig system.

    Results

    Area under the receiver-operating characteristic curve (AUROC) values of 0.71, 0.80 and 0.78, respectively, were found for KHep, LSC_N10 and LSC_N20 with regard to severe versus mild fibrosis. Significant group differences were found for KHep (borderline), LSC_N10 and LSC_N20.

    Conclusions

    Liver fibrosis stage strongly influences the hepatocyte-specific uptake of Gd-EOB-DTPA. Potentially the normalisation technique and KHep will reduce patient and system bias, yielding a robust approach to non-invasive liver function determination.

  • 15.
    Norén, Bengt
    et al.
    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.
    Lundberg, Peter
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Radiation Physics. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Ressner, Marcus
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Wirell, Staffan
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Medical Radiology.
    Almer, Sven
    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.
    Smedby, Örjan
    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. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Absolute quantification of human liver metabolite concentrations by localized in vivo 31P NMR spectroscopy in diffuse liver disease2005In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 15, no 1, p. 148-157Article in journal (Refereed)
    Abstract [en]

    Phosphorus-31 NMR spectroscopy using slice selection (DRESS) was used to investigate the absolute concentrations of metabolites in the human liver. Absolute concentrations provide more specific biochemical information compared to spectrum integral ratios. Nine patients with histopathologically proven diffuse liver disease and 12 healthy individuals were examined in a 1.5-T MR scanner (GE Signa LX Echospeed plus). The metabolite concentration quantification procedures included: (1) determination of optimal depth for the in vivo measurements, (2) mapping the detection coil characteristics, (3) calculation of selected slice and liver volume ratios using simple segmentation procedures and (4) spectral analysis in the time domain. The patients had significantly lower concentrations of phosphodiesters (PDE), 6.3±3.9 mM, and ATP-β, 3.6±1.1 mM, (P<0.05) compared with the control group (10.0±4.2 mM and 4.2±0.3 mM, respectively). The concentrations of phosphomonoesters (PME) were higher in the patient group, although this was not significant. Constructing an anabolic charge (AC) based on absolute concentrations, [PME]/([PME] + [PDE]), the patients had a significantly larger AC than the control subjects, 0.29 vs. 0.16 (P<0.005). Absolute concentration measurements of phosphorus metabolites in the liver are feasible using a slice selective sequence, and the technique demonstrates significant differences between patients and healthy subjects.

  • 16.
    Persliden, Jan
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Radio Physics.
    Beckman, Karl-Wilhelm
    Geijer, Håkan
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Radiology.
    Andersson, Torbjörn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Radiology.
    Dose-image optimisation in digital radiology with a direct digital detector: an example applied to pelvic examination2002In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 12, p. 1584-1588Article in journal (Refereed)
  • 17.
    Persliden, Jan
    et al.
    Linköping University, Department of Medicine and Care, Radio Physics. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics.
    Helmrot, Ebba
    Ryhov Hospital.
    Hjort, Per
    Ryhov Hospital.
    Resjö, Margareta
    Linköping University, Department of Medicine and Care, Radiation Physics. Linköping University, Faculty of Health Sciences.
    Dose and image quality in the comparison of analogue and digital techniques in paediatric urology examinations.2004In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 14, no 4, p. 638-644Article in journal (Refereed)
    Abstract [en]

    In paediatric radiology it has been recognised that children have a higher risk of developing cancer from the irradiation than adults (two to three times); therefore, increased attention has been directed towards the dose to the patient. In this study the effect on patient dose and image quality in replacing the exposure in micturating cystourethrography (MCUG) examinations with the stored fluoroscopy image has been investigated. In the intravenous urography (IVU) examination we compared analogue and digital image quality, but the dose measurements were performed on a phantom. Standard clinical X-ray equipment was used. Sixty-eight patients in each of two centres were studied for the MCUG. Doses were measured with a dose-area product (DAP) meter and the image quality was scored. A non-parametric statistical analysis was performed. For the IVU, a phantom was used in the dose measurements but clinical images were scored in the comparison between analogue and digital images. For the MCUG, replacing the exposure with stored fluoroscopy images lowered the DAP value from 0.77 to 0.50 Gy cm2. The image quality did not show any difference between the techniques; however, if reflux was to be graded, exposure was needed. For the IVU, the doses could be lowered by a factor of 3 using digital techniques. The image quality showed no statistical difference between the two techniques. There is a potential for a substantial dose reduction in both MUCG and IVU examinations using digital techniques.

  • 18.
    Ragnehed, Mattias
    et al.
    Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Faculty of Health Sciences.
    Dahlqvist Leinhard, Olof
    Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Faculty of Health Sciences.
    Pihlsgård, Johan
    Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Faculty of Health Sciences.
    Wirell, Staffan
    Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences.
    Sökjer, Hannibal
    Linköping University, Department of Computer and Information Science, MDI - Interaction and Service Design Research Group. Linköping University, The Institute of Technology.
    Fägerstam, Patrik
    Linköping University, Department of Medical and Health Sciences, Pharmacology. Linköping University, Faculty of Health Sciences.
    Jiang, Bo
    Linköping University, Department of Medical and Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Faculty of Health Sciences.
    Smedby, Örjan
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medical Imaging, Department of Radiology in Linköping.
    Engström, Maria
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences.
    Lundberg, Peter
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics. Östergötlands Läns Landsting, Centre for Medical Imaging, Department of Radiology in Linköping.
    Visual Grading of 2D and 3D fMRI compared to image based descriptive measures2010In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 20, no 3, p. 714-724Article in journal (Refereed)
    Abstract [en]

    A prerequisite for successful clinical use of functional Magnetic Resonance Imaging (fMRI) is the selection of an appropriate imaging sequence. In this paper, 2D and 3D fMRI sequences were compared using different image quality assessment methods. Descriptive image measures, such as activation volume and temporal signal-to-noise ratio (TSNR), were compared with results from Visual Grading Characteristics (VGC) analysis of the fMRI results. It was found that significant differences in activation volume and TSNR were not directly reflected by differences in VGC scores. The results suggest that better performance on descriptive image measures is not always an indicator of improved diagnostic quality of the fMRI results. In conclusion, in addition to descriptive image measures, it is important to include measures of diagnostic quality when comparing different fMRI data acquisition methods.

  • 19.
    Rinck, Peter A.
    et al.
    EMRF Foundation, World Trade Center, Sophia Antipolis Cedex, France.
    Ringertz, Hans
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medicine and Care, Radiology. Linköping University, Faculty of Health Sciences.
    Paul Christian Lauterbur2007In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 17, no 8, p. 2208-2210Article in journal (Other academic)
    Abstract [en]

    n/a

  • 20.
    Sandborg, Michael
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Radiation Physics. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics.
    Fransson, Sven Göran
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care. Östergötlands Läns Landsting, Heart Centre, Department of Cardiology.
    Pettersson, Håkan
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Radiation Physics. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics.
    Evaluation of patient-absorbed doses during coronary angiography and intervention by femoral and radial artery access2004In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 14, no 4, p. 653-658Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to compare the radiation dose to patients during coronary angiography (CA) and coronary intervention (percutaneous transluminal coronary angioplasty, PTCA) by the femoral or radial artery access routes. A plane-parallel ionisation chamber, mounted on an under-couch X-ray tube (Siemens Coroskop TOP with an optional dose reduction system), recorded the dose-area product (DAP) to the patient from 40 coronary angiographies and 42 coronary interventions by the femoral route. The corresponding numbers for radial access were 36 and 24, respectively. Using a human-shaped phantom, conversion factors between maximum entrance surface dose and DAP were derived for CA and CA plus PTCA, respectively. The dose to the staff was measured with TL dosimeters for 22 examinations. Fluoroscopy time and DAP were significantly (p=0.003) larger using the radial access route for coronary angiography (7.5 min, 51 Gy cm2) than the corresponding values obtained from femoral access route (4.6 min, 38 Gy cm2. For CA plus PTCA the fluoroscopy time and DAP were larger for radial access (18.4 min, 75 Gy cm2) than for femoral access (12.5 min, 47 Gy cm2, p=0.013). In our experience, radial access did significantly prolong the fluoroscopy time and increase the patient doses.

  • 21.
    Sandborg, Michael
    et al.
    Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics.
    Rossitti, Sandro
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Pettersson, Håkan
    Linköping University, Department of Medicine and Care, Radiation Physics. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics.
    Local skin and eye lens equivalent odses in interventional neuroradiology2010In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 20, no 3, p. 725-733Article in journal (Refereed)
    Abstract [en]

    Purpose  To assess patient skin and eye lens doses in interventional neuroradiology and to assess both stochastic and deterministic radiation risks. Methods  Kerma–area product (P KA) was recorded and skin doses measured using thermoluminescence dosimeters. Estimated dose at interventional reference point (IRP) was compared with measured absorbed doses. Results  The average and maximum fluoroscopy times were 32 and 189 min for coiling and 40 and 144 min for embolisation. The average and maximum P KA for coiling were 121 and 436 Gy cm2, respectively, and 189 and 677 Gy cm2 for embolisation. The average and maximum values of the measured maximum absorbed skin doses were 0.72 and 3.0 Sv, respectively, for coiling and 0.79 and 2.1 Sv for embolisation. Two out of the 52 patients received skin doses in excess of 2 Sv. The average and maximum doses to the eye lens (left eye) were 51 and 515 mSv (coiling) and 71 and 289 mSv (embolisation). Conclusion  The ratio between the measured dose and the dose at the IRP was 0.44 ± 0.18 mSv/mGy indicating that the dose displayed by the x-ray unit overestimates the maximum skin dose but is still a valuable indication of the dose. The risk of inducing skin erythema and lens cataract during our hospital procedures is therefore small.

  • 22.
    Smedby, Örjan
    et al.
    Department of Diagnostic Radiology, Uppsala University Hospital.
    Riesenfeld, V
    Karlson, B
    Jacobson, G
    Löfberg, A
    Lindgren, P G
    Ahlström, H
    Magnetic resonance angiography in the resectability assessment of suspected pancreatic tumours1997In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 7, no 5, p. 649-653Article in journal (Refereed)
    Abstract [en]

    The aim of this prospective study was to evaluate MRI, including MR angiography (MRA), in the preoperative assessment of the resectability of suspected malignancy of the pancreas. A total of 17 patients with suspected pancreatic carcinoma and planned surgery were investigated with conventional angiography, ultrasonography with Doppler technique, MRI and MRA. The MRA protocol included both 2D inflow angiography and 3D phase-contrast angiography. Surgery was carried out in 13 patients. The image quality of MRA was judged satisfactory in all cases. The findings with respect to vascular involvement agreed between the radiological methods in all but 3 cases. When the findings were correlated with the final diagnosis, one false-negative case was found for each of the three methods. The results suggest that MRI with MRA, including both the phase-contrast and inflow techniques, has a similar diagnostic value to that of conventional angiography and ultrasonography in the preoperative assessment of the portal venous system in patients with pancreatic carcinoma. Further studies are needed to establish the optimal diagnostic procedure.

  • 23.
    Smedby, Örjan
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Radiology. Östergötlands Läns Landsting, Centre for Medical Imaging, Department of Radiology UHL.
    Rostad, H
    Klaastad, Örjan
    Lilleås, F
    Tillung, T
    Fosse, E
    Functional imaging of the thoracic outlet syndrome in an open MR scanner2000In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 10, no 4, p. 597-600Article in journal (Refereed)
    Abstract [en]

    Symptoms due to thoracic outlet syndrome may present only in abduction, a position that cannot be investigated in conventional MR scanners. Therefore, this study was initiated to test MRI in an open magnet as a method for diagnosis of thoracic outlet syndrome. Ten volunteers and 7 patients with a clinical suspicion of thoracic outlet syndrome were investigated at 0.5 T in an open MR scanner. Sagittal 3D SPGR acquisitions were made in 0 and 90░abduction. In the patients, a similar data set was also obtained in maximal abduction. To assess compression, the minimum distance between the first rib and the clavicle, measured in a sagittal plane, was determined. In the neutral position, no significant difference was found between patients and controls. In 90░abduction, the patients had significantly smaller distance between rib and clavicle than the controls (14 vs 29 mm, p <0.01). On coronal reformatted images, the compression of the brachial plexus could often be visualised in abduction. Functional MR examination seems to be a useful diagnostic tool in thoracic outlet syndrome. Examination in abduction, which is feasible in an open scanner, is essential for the diagnosis.

  • 24.
    Thomas, Marianna S
    et al.
    Department of Radiology, Norfolk & Norwich University Hospital, Norwich, UK..
    Newman, David
    Department of Radiology, Norfolk & Norwich University Hospital, Norwich, UK..
    Dahlqvist Leinhard, Olof
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics.
    Karlsson, Anette
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Rosander, Johannes
    Advanced MR Analytics AB, Linköping, Sweden.
    Kasmai, Bahman
    Department of Radiology Norfolk & Norwich University Hospital, United Kingdom.
    Greenwood, Richard
    Department of Radiology Norfolk & Norwich University Hospital, United Kingdom.
    Malcolm, Paul N
    Department of Radiology Norfolk & Norwich University Hospital, United Kingdom.
    Borga, Magnus
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Toms, Andoni P
    Department of Radiology Norfolk & Norwich University Hospital, United Kingdom.
    Test-retest reliability of automated whole body and compartmental muscle volume measurements on a wide bore 3T MR system2014In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 24, no 9, p. 2279-2291Article in journal (Refereed)
    Abstract [en]

    PURPOSE:

    To measure the test-retest reproducibility of an automated system for quantifying whole body and compartmental muscle volumes using wide bore 3 T MRI.

    MATERIALS AND METHODS:

    Thirty volunteers stratified by body mass index underwent whole body 3 T MRI, two-point Dixon sequences, on two separate occasions. Water-fat separation was performed, with automated segmentation of whole body, torso, upper and lower leg volumes, and manually segmented lower leg muscle volumes.

    RESULTS:

    Mean automated total body muscle volume was 19·32 L (SD9·1) and 19·28 L (SD9·12) for first and second acquisitions (Intraclass correlation coefficient (ICC) = 1·0, 95 % level of agreement -0·32-0·2 L). ICC for all automated test-retest muscle volumes were almost perfect (0·99-1·0) with 95 % levels of agreement 1.8-6.6 % of mean volume. Automated muscle volume measurements correlate closely with manual quantification (right lower leg: manual 1·68 L (2SD0·6) compared to automated 1·64 L (2SD 0·6), left lower leg: manual 1·69 L (2SD 0·64) compared to automated 1·63 L (SD0·61), correlation coefficients for automated and manual segmentation were 0·94-0·96).

    CONCLUSION:

    Fully automated whole body and compartmental muscle volume quantification can be achieved rapidly on a 3 T wide bore system with very low margins of error, excellent test-retest reliability and excellent correlation to manual segmentation in the lower leg.

    KEY POINTS:

    • Sarcopaenia is an important reversible complication of a number of diseases. • Manual quantification of muscle volume is time-consuming and expensive. • Muscles can be imaged using in and out of phase MRI. • Automated atlas-based segmentation can identify muscle groups. • Automated muscle volume segmentation is reproducible and can replace manual measurements.

  • 25.
    Thorelius, Lars
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Radiology. Östergötlands Läns Landsting, Centre for Medical Imaging, Department of Radiology UHL.
    Contrast-enhanced ultrasound: beyond the liver.2003In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 13, p. 91-108Article in journal (Refereed)
  • 26.
    Thorelius, Lars
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Medical Radiology.
    Contrast-enhanced ultrasound in trauma2004In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 14, suppl 8, p. 43-52Article in journal (Refereed)
  • 27.
    Vitak, B
    et al.
    Linköping University, Department of Medicine and Care, Radiology. Linköping University, Faculty of Health Sciences.
    Olsen, K E
    Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pathology and Cytology. Linköping University, Faculty of Health Sciences.
    Månson, Jan-Christer
    Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pathology and Cytology. Linköping University, Faculty of Health Sciences.
    Arnesson, Lars-Gunnar
    Linköping University, Department of Biomedicine and Surgery, Surgery. Linköping University, Faculty of Health Sciences.
    Stål, Olle
    Linköping University, Department of Biomedicine and Surgery, Oncology. Linköping University, Faculty of Health Sciences.
    Tumour characteristics and survival in patients with invasive interval breast cancer classified according to mammographic findings at the latest screening: a comparison of true interval and missed interval cancers1999In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 9, no 3, p. 460-469Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to investigate whether different mammographic categories of interval cancer classified according to findings at the latest screening are associated with different distributions of prognostic factors or with different survival rates. The series consisted of all patients with invasive interval cancer detected from May 1978 to August 1995 (n = 544). The tumours were evaluated with regard to age, radiological category, interval between the latest screen and diagnosis and tumour characteristics at the time of diagnosis. We investigated possible relationships between the survival rate of patients with interval cancer and the interval between the latest screen and diagnosis, tumour characteristics and radiological category of the interval tumours. The study focused on comparison of patients with true interval and missed interval cancer. Women with mammographically occult tumours were younger than those in the other radiological categories. Comparisons of true interval cancers with overlooked or misinterpreted tumours showed equal distributions of age, tumour size, TNM stage and lymph node status. The overlooked or misinterpreted tumours showed significantly higher proportions of grade-I tumours (22 vs 11 %), tumours with low S-phase fraction (SPF; 44 vs 24 %) and oestrogen receptor (ER) positive tumours (72 vs 57 %). However, analyses of survival rates disclosed no clear differences between the two radiological categories. Radiological category and interval between the latest screen and diagnosis were not genuine predictors of the prognosis in patients with invasive interval breast cancer. No certain prognostic difference existed between true interval cancers and overlooked or misinterpreted interval breast cancers, despite higher proportions of grade-I tumours, ER positive tumours and tumours with low SPF in the latter group.

  • 28.
    West, Janne
    et al.
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences.
    Warntjes, Marcel
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Clinical Physiology UHL.
    Lundberg, Peter
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics UHL. Östergötlands Läns Landsting, Centre for Diagnostics, Department of Radiology in Linköping.
    Novel whole brain segmentation and volume estimation using quantitative MRI2012In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 22, no 5, p. 998-1007Article in journal (Refereed)
    Abstract [en]

    OBJECTIVES:

    Brain segmentation and volume estimation of grey matter (GM), white matter (WM) and cerebro-spinal fluid (CSF) are important for many neurological applications. Volumetric changes are observed in multiple sclerosis (MS), Alzheimer's disease and dementia, and in normal aging. A novel method is presented to segment brain tissue based on quantitative magnetic resonance imaging (qMRI) of the longitudinal relaxation rate R(1), the transverse relaxation rate R(2) and the proton density, PD.

    METHODS:

    Previously reported qMRI values for WM, GM and CSF were used to define tissues and a Bloch simulation performed to investigate R(1), R(2) and PD for tissue mixtures in the presence of noise. Based on the simulations a lookup grid was constructed to relate tissue partial volume to the R(1)-R(2)-PD space. The method was validated in 10 healthy subjects. MRI data were acquired using six resolutions and three geometries.

    RESULTS:

    Repeatability for different resolutions was 3.2% for WM, 3.2% for GM, 1.0% for CSF and 2.2% for total brain volume. Repeatability for different geometries was 8.5% for WM, 9.4% for GM, 2.4% for CSF and 2.4% for total brain volume.

    CONCLUSION:

    We propose a new robust qMRI-based approach which we demonstrate in a patient with MS. KEY POINTS : • A method for segmenting the brain and estimating tissue volume is presented • This method measures white matter, grey matter, cerebrospinal fluid and remaining tissue • The method calculates tissue fractions in voxel, thus accounting for partial volume • Repeatability was 2.2% for total brain volume with imaging resolution <2.0 mm.

  • 29.
    Wilczek, M L
    et al.
    Karolinska University Hospital, Stockholm, Sweden .
    Kälvesten, Johan
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Sectra Imtec AB, Linköping, Sweden .
    Algulin, J
    Sectra Imtec AB, Linkoping, Sweden .
    Beiki, O
    Karolinska Institutet, Stockholm, Sweden .
    Brismar, T B
    Karolinska University Hospital, Stockholm, Sweden .
    Digital X-ray radiogrammetry of hand or wrist radiographs can predict hip fracture risk-a study in 5,420 women and 2,837 men2013In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 23, no 5, p. 1383-1391Article in journal (Refereed)
    Abstract [en]

    To assess whether digital X-ray radiogrammetry (DXR) analysis of standard clinical hand or wrist radiographs obtained at emergency hospitals can predict hip fracture risk. less thanbrgreater than less thanbrgreater thanA total of 45,538 radiographs depicting the left hand were gathered from three emergency hospitals in Stockholm, Sweden. Radiographs with insufficiently included metacarpal bone, fractures in measurement regions, foreign material or unacceptable positioning were manually excluded. A total of 18,824 radiographs from 15,072 patients were analysed with DXR, yielding a calculated BMD equivalent (DXR-BMD). Patients were matched with the national death and inpatient registers. Inclusion criteria were age a parts per thousand yen 40 years, no prior hip fracture and observation time andgt; 7 days. Hip fractures were identified via ICD-10 codes. Age-adjusted hazard ratio per standard deviation (HR/SD) was calculated using Cox regression. less thanbrgreater than less thanbrgreater than8,257 patients (65.6 % female, 34.4 % male) met the inclusion criteria. One hundred twenty-two patients suffered a hip fracture after their radiograph. The fracture group had a significantly lower DXR-BMD than the non-fracture group when adjusted for age. The HR/SD for hip fracture was 2.52 and 2.08 in women and men respectively. The area under the curve was 0.89 in women and 0.84 in men. less thanbrgreater than less thanbrgreater thanDXR analysis of wrist and hand radiographs obtained at emergency hospitals predicts hip fracture risk in women and men. less thanbrgreater than less thanbrgreater thanKey Points less thanbrgreater than less thanbrgreater thanDigital X-ray radiogrammetry of emergency hand/wrist radiographs predicts hip fracture risk. less thanbrgreater than less thanbrgreater thanDigital X-ray radiogrammetry (DXR) predicts hip fracture risk in both women and men. less thanbrgreater than less thanbrgreater thanOsteoporosis can potentially be identified in patients with suspected wrist fractures. less thanbrgreater than less thanbrgreater thanDXR can potentially be used for selective osteoporosis screening.

  • 30.
    Zech, Wolf-Dieter
    et al.
    Institute of Forensic Medicine University of Bern Switzerland.
    Schwendener, Nicole
    Institute of Forensic Medicine University of Bern Switzerland.
    Persson, Anders
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Radiology in Linköping.
    Bertus Warntjes, Marcel, Jan
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Jackowski, Christian
    Institute of Forensic Medicine University of Bern Switzerland.
    Temperature dependence of postmortem MR quantification for soft tissue discrimination2015In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Temperature dependence of postmortem MR quantification for soft tissue discrimination, Vol. 25, no 8, p. 2381-2389Article in journal (Refereed)
    Abstract [en]

    Objectives To investigate and correct the temperature dependence of postmortem MR quantification used for soft tissue characterization and differentiation in thoraco-abdominal organs. Material and methods Thirty-five postmortem short axis cardiac 3-T MR examinations were quantified using a quantification sequence. Liver, spleen, left ventricular myocardium, pectoralis muscle and subcutaneous fat were analysed in cardiac short axis images to obtain mean T1, T2 and PD tissue values. The core body temperature was measured using a rectally inserted thermometer. The tissue-specific quantitative values were related to the body core temperature. Equations to correct for temperature differences were generated. Results In a 3D plot comprising the combined data of T1, T2 and PD, different organs/tissues could be well differentiated from each other. The quantitative values were influenced by the temperature. T1 in particular exhibited strong temperature dependence. The correction of quantitative values to a temperature of 37 °C resulted in better tissue discrimination. Conclusion Postmortem MR quantification is feasible for soft tissue discrimination and characterization of thoracoabdominal organs. This provides a base for computer-aided diagnosis and detection of tissue lesions. The temperature dependence of the T1 values challenges postmortem MR quantification. Equations to correct for the temperature dependence are provided.

  • 31.
    Zech, Wolf-Dieter
    et al.
    University of Bern, Switzerland.
    Schwendener, Nicole
    University of Bern, Switzerland.
    Persson, Anders
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Radiology in Linköping.
    Warntjes, Marcel Jan Bertus
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Jackowski, Christian
    University of Bern, Switzerland.
    Postmortem MR quantification of the heart for characterization and differentiation of ischaemic myocardial lesions2015In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 25, no 7, p. 2067-2073Article in journal (Refereed)
    Abstract [en]

    Recently, an MRI quantification sequence has been developed which can be used to acquire T1- and T2-relaxation times as well as proton density (PD) values. Those three quantitative values can be used to describe soft tissue in an objective manner. The purpose of this study was to investigate the applicability of quantitative cardiac MRI for characterization and differentiation of ischaemic myocardial lesions of different age. Fifty post-mortem short axis cardiac 3 T MR examinations have been quantified using a quantification sequence. Myocardial lesions were identified according to histology and appearance in MRI images. Ischaemic lesions were assessed for mean T1-, T2- and proton density values. Quantitative values were plotted in a 3D-coordinate system to investigate the clustering of ischaemic myocardial lesions. A total of 16 myocardial lesions detected in MRI images were histologically characterized as acute lesions (n = 8) with perifocal oedema (n = 8), subacute lesions (n = 6) and chronic lesions (n = 2). In a 3D plot comprising the combined quantitative values of T1, T2 and PD, the clusters of all investigated lesions could be well differentiated from each other. Post-mortem quantitative cardiac MRI is feasible for characterization and discrimination of different age stages of myocardial infarction. aEuro cent MR quantification is feasible for characterization of different stages of myocardial infarction. aEuro cent The results provide the base for computer-aided MRI cardiac infarction diagnosis. aEuro cent Diagnostic criteria may also be applied for living patients.

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