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  • 1.
    Bolger, Ann F
    et al.
    Linköpings universitet, Institutionen för medicin och vård, Centrum för medicinsk bildvetenskap och visualisering. Linköpings universitet, Hälsouniversitetet.
    Heiberg, Einar
    Linköpings universitet, Institutionen för medicin och vård, Klinisk fysiologi. Linköpings universitet, Institutionen för medicin och vård, Centrum för medicinsk bildvetenskap och visualisering. Linköpings universitet, Hälsouniversitetet.
    Karlsson, Matts
    Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Institutionen för medicin och vård, Klinisk fysiologi. Linköpings universitet, Hälsouniversitetet.
    Wigström, Lars
    Linköpings universitet, Institutionen för medicin och vård, Centrum för medicinsk bildvetenskap och visualisering. Linköpings universitet, Institutionen för medicin och vård, Klinisk fysiologi. Linköpings universitet, Hälsouniversitetet.
    Engvall, Jan
    Linköpings universitet, Institutionen för medicin och vård, Centrum för medicinsk bildvetenskap och visualisering. Linköpings universitet, Institutionen för medicin och vård, Klinisk fysiologi. Linköpings universitet, Hälsouniversitetet.
    Sigfridsson, Andreas
    Linköpings universitet, Institutionen för medicin och vård, Centrum för medicinsk bildvetenskap och visualisering. Linköpings universitet, Institutionen för medicin och vård, Klinisk fysiologi. Linköpings universitet, Hälsouniversitetet.
    Ebbers, Tino
    Linköpings universitet, Institutionen för medicin och vård, Centrum för medicinsk bildvetenskap och visualisering. Linköpings universitet, Institutionen för medicin och vård, Klinisk fysiologi. Linköpings universitet, Hälsouniversitetet.
    Escobar Kvitting, John-Peder
    Linköpings universitet, Institutionen för medicin och vård, Centrum för medicinsk bildvetenskap och visualisering. Linköpings universitet, Institutionen för medicin och vård, Klinisk fysiologi. Linköpings universitet, Hälsouniversitetet.
    Carlhäll, Carljohan
    Linköpings universitet, Institutionen för medicin och vård, Centrum för medicinsk bildvetenskap och visualisering. Linköpings universitet, Institutionen för medicin och vård, Klinisk fysiologi. Linköpings universitet, Hälsouniversitetet.
    Wranne, Bengt
    Linköpings universitet, Institutionen för medicin och vård, Centrum för medicinsk bildvetenskap och visualisering. Linköpings universitet, Institutionen för medicin och vård, Klinisk fysiologi. Linköpings universitet, Hälsouniversitetet.
    Transit of blood flow through thehuman left ventricle mapped by cardiovascular magnetic resonance2007Inngår i: Journal of Cardiovascular Magnetic Resonance, ISSN 1097-6647, E-ISSN 1532-429X, Vol. 9, nr 5, s. 741-747Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 2.
    Carlhäll, Carljohan
    Linköpings universitet, Institutionen för medicin och vård, Klinisk fysiologi. Linköpings universitet, Institutionen för medicin och vård, Centrum för medicinsk bildvetenskap och visualisering. Linköpings universitet, Hälsouniversitetet.
    Annular dynamics of the human heart: novel echocardiographic approaches to assess ventricular function2004Doktoravhandling, med artikler (Annet vitenskapelig)
    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.

    Delarbeid
    1. A novel method to assess systolic ventricular function using atrioventricular plane displacement: a study in young healthy males and patients with heart disease
    Åpne denne publikasjonen i ny fane eller vindu >>A novel method to assess systolic ventricular function using atrioventricular plane displacement: a study in young healthy males and patients with heart disease
    2004 (engelsk)Inngår i: Clinical Physiology and Functional Imaging, ISSN 1475-0961, E-ISSN 1475-097X, Vol. 24, nr 4, s. 190-195Artikkel i tidsskrift (Fagfellevurdert) 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.

    Emneord
    echocardiography, overestimation, reference values, systolic performance, ventricular long axis motion
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-23404 (URN)10.1111/j.1475-097X.2004.00547.x (DOI)2846 (Lokal ID)2846 (Arkivnummer)2846 (OAI)
    Tilgjengelig fra: 2009-10-07 Laget: 2009-10-07 Sist oppdatert: 2017-12-13bibliografisk kontrollert
    2. Is left ventricular postsystolic long-axis shortening a marker for severity of hypertensive heart disease?
    Åpne denne publikasjonen i ny fane eller vindu >>Is left ventricular postsystolic long-axis shortening a marker for severity of hypertensive heart disease?
    2003 (engelsk)Inngår i: American Journal of Cardiology, ISSN 0002-9149, E-ISSN 1879-1913, Vol. 91, nr 12, s. 1490-1493Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    No abstract available.

    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-26833 (URN)10.1016/S0002-9149(03)00407-7 (DOI)11448 (Lokal ID)11448 (Arkivnummer)11448 (OAI)
    Tilgjengelig fra: 2009-10-08 Laget: 2009-10-08 Sist oppdatert: 2017-12-13bibliografisk kontrollert
    3. Atrioventricular plane displacement correlates closely to circulatory dimensions but not to ejection fraction in normal young subjects
    Åpne denne publikasjonen i ny fane eller vindu >>Atrioventricular plane displacement correlates closely to circulatory dimensions but not to ejection fraction in normal young subjects
    2001 (engelsk)Inngår i: Clinical Physiology, ISSN 0144-5979, E-ISSN 1365-2281, Vol. 21, nr 5, s. 621-628Artikkel i tidsskrift (Fagfellevurdert) 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.

    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-26832 (URN)10.1046/j.1365-2281.2001.00356.x (DOI)11447 (Lokal ID)11447 (Arkivnummer)11447 (OAI)
    Tilgjengelig fra: 2009-10-08 Laget: 2009-10-08 Sist oppdatert: 2017-12-13bibliografisk kontrollert
    4. Contribution of mitral annular excursion and shape dynamics to total left ventricular volume change
    Åpne denne publikasjonen i ny fane eller vindu >>Contribution of mitral annular excursion and shape dynamics to total left ventricular volume change
    Vise andre…
    2004 (engelsk)Inngår i: American Journal of Physiology. Heart and Circulatory Physiology, ISSN 0363-6135, E-ISSN 1522-1539, Vol. 287, nr 4, s. H1836-H1841Artikkel i tidsskrift (Fagfellevurdert) 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.

    Emneord
    annular physiology, ventricular long axis function, echocardiography, three dimension, four dimension
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-24050 (URN)10.1152/ajpheart.00103.2004 (DOI)3608 (Lokal ID)3608 (Arkivnummer)3608 (OAI)
    Tilgjengelig fra: 2009-10-07 Laget: 2009-10-07 Sist oppdatert: 2017-12-13bibliografisk kontrollert
  • 3.
    Carlhäll, Carljohan
    et al.
    Linköpings universitet, Institutionen för medicin och vård, Klinisk fysiologi. Linköpings universitet, Institutionen för medicin och vård, Centrum för medicinsk bildvetenskap och visualisering. Linköpings universitet, Hälsouniversitetet.
    Wigström, Lars
    Linköpings universitet, Institutionen för medicin och vård, Klinisk fysiologi. Linköpings universitet, Institutionen för medicin och vård, Centrum för medicinsk bildvetenskap och visualisering. Linköpings universitet, Hälsouniversitetet.
    Heiberg, Einar
    Linköpings universitet, Institutionen för medicin och vård, Klinisk fysiologi. Linköpings universitet, Institutionen för medicin och vård, Centrum för medicinsk bildvetenskap och visualisering. Linköpings universitet, Hälsouniversitetet.
    Karlsson, Matts
    Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Institutionen för medicin och vård, Centrum för medicinsk bildvetenskap och visualisering. Linköpings universitet, Hälsouniversitetet.
    Bolger, A. F.
    Department of Medicine/Cardiology, University of California, San Francisco, California.
    Nylander, Eva
    Linköpings universitet, Institutionen för medicin och vård, Klinisk fysiologi. Linköpings universitet, Institutionen för medicin och vård, Centrum för medicinsk bildvetenskap och visualisering. Linköpings universitet, Hälsouniversitetet.
    Contribution of mitral annular excursion and shape dynamics to total left ventricular volume change2004Inngår i: American Journal of Physiology. Heart and Circulatory Physiology, ISSN 0363-6135, E-ISSN 1522-1539, Vol. 287, nr 4, s. H1836-H1841Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 4.
    Escobar Kvitting, John-Peder
    Linköpings universitet, Institutionen för medicin och vård, Klinisk fysiologi. Linköpings universitet, Institutionen för medicin och vård, Centrum för medicinsk bildvetenskap och visualisering. Linköpings universitet, Hälsouniversitetet.
    Quantification of cardiovascular flow and motion: aspects of regional myocardial function and flow patterns in the aortic root and the aorta2004Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Quantification of cardiovascular flow and motion is essential in the diagnosis, treatment and follow-up of cardiovascular disease. The accuracy and quantification of many imaging methods used in this field have important shortfalls, however, that result from limitations in spatial and temporal dimensions. Improvement in application of these methods requires an in-depth understanding of the technical and perceptual aspects that contribute to errors in their use.

    Visual assessment of echocardiographic images for asynchrony in regional myocardial motion during systolic contraction is an example of the need for better definition of limitations. The discernible delay in wall motion improved from 89 ms to 71 ms by allowing side-by-side comparison to normal motion. Clinically important delays are almost certainly missed with current "eyeballing" methods. Different and more quantitative approaches to this problem have been developed. Anatomic M-mode (AMM) assesses motion along an arbitrary line within a two-dimensional (2D) image, and was demonstrably robust in the clinical setting when used with second harmonic imaging at a depth less than 20 cm and with angle correction ofless than 60°. Doppler myocardial (DMI) imaging and strain rate imaging (SRI) were also shown to reliably demonstrate the effects of inotropic stimulation, total and severe ischemia on asynchrony in a closed chest pig model. Quantification of the changes induced by inotropy and total ischemia was possible with both methods, but the effects of stunning were not. Regional myocardial function and cardiovascular flow can also be assessed with time-resolved, three-directional, three-dimensional (3D) velocity data acquired using phase contrast magnetic resonance imaging (PC-MRI). This multidimensional data demonstrated longitudinal velocity gradients along all four walls of the left ventricle, with miuirnal apical longitudinal motion. The 3D velocity vector from single points in the ventricular wall shows that the motion over the cardiac cycle is complex in all dimensions. The flow patterns in the aortic root were also studied using time-resolved 3D PC-MRI in normal volunteers and patients who had undergone aortic-valve sparing surgery using straight Dacron grafts. In normals, vortices appeared in the sinuses of Valsalva in late systole, increased in size with the deceleration of aortic outflow and moved together as the valve closed in early diastole. These normal flow structures have never before been demonstrated in three dimensions in man. In the postoperative patients, lacking both sinuses and sinotubular junction, vortices were not observed.

    Many imaging methods can be improved by a critical definition of the limits oftheir reliability. This can prompt the modifications and new methods which allow us to move beyond the original shortcomings and contribute new knowledge regarding the pathophysiology of cardiovascular disease.

    Delarbeid
    1. How accurate is visual assessment of synchronicity in myocardial motion? An in vitro study with computer-simulated regional delay in myocardial motion: clinical implications for rest and stress echocardiography studies
    Åpne denne publikasjonen i ny fane eller vindu >>How accurate is visual assessment of synchronicity in myocardial motion? An in vitro study with computer-simulated regional delay in myocardial motion: clinical implications for rest and stress echocardiography studies
    1999 (engelsk)Inngår i: Journal of the American Society of Echocardiography, ISSN 0894-7317, E-ISSN 1097-6795, Vol. 12, nr 9, s. 698-705Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Asynchronicity in echocardiographic images is normally assessed visually. No prior quantitative studies have determined the limitations of this approach. To quantify visual recognition of myocardial asynchronicity in echocardiographic images, computer-simulated delay phantom loops were generated from a 3.3 MHz digital image data from a normal left ventricular short-axis heart cycle acquired at 55 frames per second. Six expert observers visually assessed 30 abnormal and 3 normal loops with differing computer-induced delay patterns on 3 occasions and in this optimally simulated environment could recognize only single delays of 89 ms or more. This was improved to 71 ms or more by use of side-by-side (normal versus abnormal) comparative review. Thus visual assessment of clinically important regional delay in rest or stress echo images is limited.

    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-26982 (URN)10.1016/S0894-7317(99)70019-2 (DOI)11617 (Lokal ID)11617 (Arkivnummer)11617 (OAI)
    Tilgjengelig fra: 2009-10-08 Laget: 2009-10-08 Sist oppdatert: 2017-12-13
    2. Anatomic M-mode echocardiography: a new approach to assess regional myocardial function - A comparative in vivo and in vitro study of both fundamental and second harmonic imaging modes
    Åpne denne publikasjonen i ny fane eller vindu >>Anatomic M-mode echocardiography: a new approach to assess regional myocardial function - A comparative in vivo and in vitro study of both fundamental and second harmonic imaging modes
    Vise andre…
    1999 (engelsk)Inngår i: Journal of the American Society of Echocardiography, ISSN 0894-7317, E-ISSN 1097-6795, Vol. 12, nr 5, s. 300-307Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Objective: To evaluate the accuracy of anatomic M-mode echocardiography (AMM).

    Methods: Eight phantoms were rotated on a device at different insonation depths (IDs) in a water beaker. They were insonated with different transducer frequencies in fundamental imaging (FI) and second harmonic imaging (SHI), and the diameters were assessed with conventional M-mode echocardiography (CMM) and AMM with the applied angle correction (AC) after rotation. In addition, left ventricular wall dimensions were measured with CMM and AMM in FI and SHI in 10 volunteers.

    Results: AC had the greatest effect on the measurement error in AMM followed by ID (AC: R2 = 0.295, ID: R2 = 0.268; P < .0001). SHI improved the accuracy, and a difference no longer existed between CMM and AMM with an AC up to 60 degrees. In vivo the limit of agreement between AMM and CMM was -1.7 to +1.8 mm in SHI.

    Conclusion: Within its limitations (AC < 60 degrees; ID < 20 cm), AMM could be a robust tool in clinical practice.

    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-26981 (URN)10.1016/S0894-7317(99)70050-7 (DOI)11616 (Lokal ID)11616 (Arkivnummer)11616 (OAI)
    Tilgjengelig fra: 2009-10-08 Laget: 2009-10-08 Sist oppdatert: 2017-12-13
    3. Regional asynchrony in acute ischemia and stunning: an experimental myocardial velocity and strain rate imaging study
    Åpne denne publikasjonen i ny fane eller vindu >>Regional asynchrony in acute ischemia and stunning: an experimental myocardial velocity and strain rate imaging study
    Vise andre…
    (engelsk)Manuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    Objective: To quantify motion and deformation asynchrony using Doppler myocardial imaging (DMI) during acute total ischemia, and stunning of the posterior left ventricular wall (PW) in comparison with the interventricular septum (IVS).

    Methods: Ischemia of the PW was induced in closed-chest pigs using an angioplasty balloon positioned in the circumflex coronary artery. Animals were divided into three groups: normal controls (Group I - n = 6), total ischemia (Group II - n = 8), and stunning (Group III - n = 6) induced by coronary occlusion with distal coronary perfusion maintained via a perfusion catheter coupled to a roller pump (Group III). In addition, a 2-step dobutamine challenge (5 and 10 µg.kg-1 .min-1) was performed in groups I and III. Doppler myocardial velocity and strain rate cineloops were acquired from a parasternal short axis view.

    Results: The pre-ejection time (T1) and the duration of regional mechanical systole (SYS) became shorter with inotropic stimulation. During total ischemia T1 was prolonged and SYS shortened significantly compared to baseline values [62 ± 14 vs. 55 ± 13 ms (P < 0.05)], [164 ± 13 vs. 240 ± 27 ms (P < 0.001)], respectively. The fraction T1/SYS was accordingly higher. No changes were observed for the contra lateral non-ischemic wall. In group III, the post-ischemic myocardium had a similar response as non-ischemic myocardium to the dobutamine challenge.

    Conclusion: Consistent changes in local pre-ejection time and regional mechanical systole are induced by intropic stimulation and by total ischemia. However, the response to intropic stimulation did not differ between normal and stunned myocardium.

    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-84958 (URN)
    Tilgjengelig fra: 2012-10-29 Laget: 2012-10-29 Sist oppdatert: 2012-10-29
    4. Three-directional myocardial motion assessed using 3D phase contrast MRI
    Åpne denne publikasjonen i ny fane eller vindu >>Three-directional myocardial motion assessed using 3D phase contrast MRI
    Vise andre…
    2004 (engelsk)Inngår i: Journal of Cardiovascular Magnetic Resonance, ISSN 1097-6647, E-ISSN 1532-429X, Vol. 6, nr 3, s. 627-636Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Regional myocardial function is a complex entity consisting of motion in three dimensions (3D). Besides magnetic resonance imaging (MRI), no other noninvasive technique can give a true 3D description of cardiac motion. Using a time‐resolved 3D phase contrast technique, three‐dimensional image volumes containing myocardial velocity data in six normal volunteers were acquired. Coordinates and velocity information were extracted from nine points placed in different myocardial segments in the left ventricle (LV), and decomposed into longitudinal (VL), radial (VR), and circumferential (VC) velocity components. Our findings confirm a longitudinal apex‐to‐base gradient for the LV, with only a small motion of the apex. The mean velocity for VL for all the basal segments was higher compared to the midsegments during systole [3.5 ± 1.2 vs. 2.5 ± 1.7 cm/s (p < 0.01)], early filling [− 6.9 ± 1.8 vs. − 4.9 ± 1.8 cm/s (p < 0.001)], and during atrial contraction [− 2.2 ± 1.4 vs. − 1.6 ± 1.3 cm/s (p < 0.05)]. A similar pattern was observed when comparing velocities from the midsegments to the apex. Radial velocity was higher during early filling in the midportion of the lateral [− 4.9 ± 2.7 vs. − 3.2 ± 1.6 cm/s (p < 0.05)] wall compared to the basal segments, no difference was observed for the septal [− 2.0 ± 1.5 vs. − 0.3 ± 2.5 cm/s (p = 0.15)], anterior [− 5.8 ± 3.3 vs. − 4.0 ± 1.7 cm/s (p = 0.17)], and posterior [− 2.3 ± 2.1 vs. − 2.5 ± 1.0 cm/s (p = 0.78)] walls. When observing the myocardial velocity in a single point and visualizing the movement of the main direction of the velocities in this point as vectors in velocity vector plots like planes, it is clear that myocardial movement is by no means one dimensional. In conclusion, our time‐resolved 3D, phase contrast MRI technique makes it feasible to extract myocardial velocities from anywhere in the myocardium, including all three velocity components without the need for positioning any slices at the time of acquisition.

    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-24306 (URN)10.1081/JCMR-120038692 (DOI)3929 (Lokal ID)3929 (Arkivnummer)3929 (OAI)
    Tilgjengelig fra: 2009-10-07 Laget: 2009-10-07 Sist oppdatert: 2017-12-13
    5. Flow patterns in the aortic root and the aorta studied with time-resolved, 3-dimensional, phase-contrast magnetic resonance imaging: implications for aortic valve–sparing surgery
    Åpne denne publikasjonen i ny fane eller vindu >>Flow patterns in the aortic root and the aorta studied with time-resolved, 3-dimensional, phase-contrast magnetic resonance imaging: implications for aortic valve–sparing surgery
    Vise andre…
    2004 (engelsk)Inngår i: Journal of Thoracic and Cardiovascular Surgery, ISSN 0022-5223, E-ISSN 1097-685X, Vol. 127, nr 6, s. 1602-1607Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Objective

    Sparing the aortic valve has become a surgical option for patients who require repair of aortic root ectasia and have normal valve leaflets. Surgical approaches to valve sparing differ with regard to preservation of the native sinuses of Valsalva. The role of the sinuses and the importance of maintaining them remain controversial.

    Methods

    By using a time-resolved, 3-dimensional, phase-contrast magnetic resonance imaging technique, aortic root and aortic blood velocity data were acquired from 2 patients with Marfan syndrome 6 months after aortic valve–sparing surgery with straight Dacron grafts and contrasted with data from 6 normal volunteers.

    Results

    In normal aortas vortical blood flow became apparent in the individual sinuses after peak systole. The vortices filled the available space behind the valve leaflets and persisted until diastole, expanding and moving inward during aortic valve closure. In contrast, no vortices were observed in the postoperative patients with Marfan syndrome with negligible sinuses.

    Conclusions

    Changes in supravalvular flow accompany loss of sinus architecture. Whether the presence, size, and velocity of supravalvular vortices affects the function or durability of the preserved aortic valve remains to be studied.

    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-24305 (URN)10.1016/j.jtcvs.2003.10.042 (DOI)3927 (Lokal ID)3927 (Arkivnummer)3927 (OAI)
    Tilgjengelig fra: 2009-10-07 Laget: 2009-10-07 Sist oppdatert: 2017-12-13
  • 5.
    Escobar Kvitting, John-Peder
    et al.
    Linköpings universitet, Institutionen för medicin och vård, Klinisk fysiologi. Linköpings universitet, Institutionen för medicin och vård, Centrum för medicinsk bildvetenskap och visualisering. Linköpings universitet, Hälsouniversitetet.
    Ebbers, Tino
    Linköpings universitet, Institutionen för medicin och vård, Klinisk fysiologi. Linköpings universitet, Institutionen för medicin och vård, Centrum för medicinsk bildvetenskap och visualisering. Linköpings universitet, Hälsouniversitetet.
    Engvall, Jan
    Linköpings universitet, Institutionen för medicin och vård, Klinisk fysiologi. Linköpings universitet, Institutionen för medicin och vård, Centrum för medicinsk bildvetenskap och visualisering. Linköpings universitet, Hälsouniversitetet.
    Sutherland, George R.
    Department of Cardiology, University Hospital Gasthuisberg, Leuven, Belgium.
    Wranne, Bengt
    Linköpings universitet, Institutionen för medicin och vård, Klinisk fysiologi. Linköpings universitet, Institutionen för medicin och vård, Centrum för medicinsk bildvetenskap och visualisering. Linköpings universitet, Hälsouniversitetet.
    Wigström, Lars
    Linköpings universitet, Institutionen för medicin och vård, Klinisk fysiologi. Linköpings universitet, Institutionen för medicin och vård, Centrum för medicinsk bildvetenskap och visualisering. Linköpings universitet, Hälsouniversitetet.
    Three-directional myocardial motion assessed using 3D phase contrast MRI2004Inngår i: Journal of Cardiovascular Magnetic Resonance, ISSN 1097-6647, E-ISSN 1532-429X, Vol. 6, nr 3, s. 627-636Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Regional myocardial function is a complex entity consisting of motion in three dimensions (3D). Besides magnetic resonance imaging (MRI), no other noninvasive technique can give a true 3D description of cardiac motion. Using a time‐resolved 3D phase contrast technique, three‐dimensional image volumes containing myocardial velocity data in six normal volunteers were acquired. Coordinates and velocity information were extracted from nine points placed in different myocardial segments in the left ventricle (LV), and decomposed into longitudinal (VL), radial (VR), and circumferential (VC) velocity components. Our findings confirm a longitudinal apex‐to‐base gradient for the LV, with only a small motion of the apex. The mean velocity for VL for all the basal segments was higher compared to the midsegments during systole [3.5 ± 1.2 vs. 2.5 ± 1.7 cm/s (p < 0.01)], early filling [− 6.9 ± 1.8 vs. − 4.9 ± 1.8 cm/s (p < 0.001)], and during atrial contraction [− 2.2 ± 1.4 vs. − 1.6 ± 1.3 cm/s (p < 0.05)]. A similar pattern was observed when comparing velocities from the midsegments to the apex. Radial velocity was higher during early filling in the midportion of the lateral [− 4.9 ± 2.7 vs. − 3.2 ± 1.6 cm/s (p < 0.05)] wall compared to the basal segments, no difference was observed for the septal [− 2.0 ± 1.5 vs. − 0.3 ± 2.5 cm/s (p = 0.15)], anterior [− 5.8 ± 3.3 vs. − 4.0 ± 1.7 cm/s (p = 0.17)], and posterior [− 2.3 ± 2.1 vs. − 2.5 ± 1.0 cm/s (p = 0.78)] walls. When observing the myocardial velocity in a single point and visualizing the movement of the main direction of the velocities in this point as vectors in velocity vector plots like planes, it is clear that myocardial movement is by no means one dimensional. In conclusion, our time‐resolved 3D, phase contrast MRI technique makes it feasible to extract myocardial velocities from anywhere in the myocardium, including all three velocity components without the need for positioning any slices at the time of acquisition.

  • 6.
    Gustafsson, M C
    et al.
    Linköpings universitet, Institutionen för nervsystem och rörelseorgan, Neurologi. Linköpings universitet, Hälsouniversitetet.
    Dahlqvist Leinhard, Olof
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Institutionen för medicin och hälsa, Medicinsk radiofysik. Linköpings universitet, Hälsouniversitetet.
    Jaworski, J
    Linköpings universitet, Institutionen för nervsystem och rörelseorgan, Neurologi. Linköpings universitet, Hälsouniversitetet.
    Lundberg, Peter
    Linköpings universitet, Institutionen för medicin och vård, Medicinsk radiofysik. Linköpings universitet, Institutionen för medicin och vård, Radiologi. Linköpings universitet, Institutionen för medicin och vård, Centrum för medicinsk bildvetenskap och visualisering. Linköpings universitet, Hälsouniversitetet.
    Landtblom, Anne-Marie
    Linköpings universitet, Institutionen för nervsystem och rörelseorgan, Neurologi. Linköpings universitet, Hälsouniversitetet.
    Low Choline Concentrations in Normal-Appearing White Matter of Patients with Multiple Sclerosis and Normal MR Imaging Brain Scans2007Inngår i: American Journal of Neuroradiology, ISSN 0195-6108, E-ISSN 1936-959X, Vol. 28, nr 7, s. 1306-1312Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    BACKGROUND AND PURPOSE: Spectroscopic studies (1H-MR spectroscopy) of normal-appearing white matter (NAWM) in patients with multiple sclerosis (MS) with MR imaging brain lesions have already been performed, but our intention was to investigate NAWM in MS patients who lack brain lesions to elucidate whether the same pathologic changes could be identified.

    MATERIALS AND METHODS: We checked 350 medical files of patients with MS who are registered in our institution. Fourteen patients (11 women and 3 men; mean age, 48.6 years; handicap score, Expanded Disability Status Scale [EDSS] 2.9; range, 1–6.5) with clinically definite MS and a normal MR imaging of the brain were included. 1H-MR spectroscopy was performed in 4 voxels (size approximately 17 × 17 × 17 mm3) using absolute quantification of metabolite concentrations. Fourteen healthy control subjects (11 women and 3 men; mean age, 43.3 years) were analyzed in the same way.

    RESULTS: Significant differences in absolute metabolite concentrations were observed, with the patients with MS showing a lower total concentration of N-acetyl compounds (tNA), including N-acetylaspartate and N-acetyl aspartylglutamate (13.5 mmol/L versus 14.6 mmol/L; P = .002) compared with the healthy control subjects. Unexpectedly, patients with MS presented significantly lower choline-containing compounds (Cho) compared with healthy control subjects (2.2 mmol/L versus 2.4 mmol/L; P < .001). The EDSS showed a positive correlation to myo-inositol concentrations (0.14 mmol/L per EDSS; r2 = 0.06) and a negative correlation to tNA concentrations (−0.41 mmol/L per EDSS; r2 = 0.22).

    CONCLUSION: The unexpected finding of lower Cho concentrations has not been reported previously. We suggest that patients with MS who lack lesions in the brain constitute a separate entity and may have increased protective or healing abilities.

  • 7.
    Heiberg, Einar
    Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Institutionen för medicin och vård, Centrum för medicinsk bildvetenskap och visualisering. Linköpings universitet, Tekniska högskolan.
    Automated feature detection in multidimensional images2005Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Manual identification of structures and features in multidimensional images is at best time consuming and operator dependent. Feature identification need to be accurate, repeatable and quantitative.

    This thesis presents novel methods for automated feature detection in multidimensional images that are independent on imaging modality. Feature detection is described at two abstraction levels. At the first low level the image is regionally processed to find local or regional features. In the second medium level results are taken from the low level feature detection and grouped into objects or parts that can be quantified. A key to quantification of cardiac function is delineation of the cardiac walls which is a difficult task. Two different methods are described and evaluated for delineation of the left ventricular wall from anatomical images. The results show that semi-automatic delineation is a huge time saver compared to manual delineation. To obtain a robust results as much a priori and image information as possible should be used in the delineation process. Regional cardiac wall function is further studied by deriving and analyzing strain-rate tensors from velocity encoded images. For flow encoded images novel methods to find regional flow structures such as vortex cores, flow based delineation, and flow quantification are proposed. These methods are applied to study blood flow in the human heart, but the techniques outlined are general and can be applied to a wide array of flow conditions.

    Delarbeid
    1. Segmentation of echo cardiographic image sequences using spatio-temporal information
    Åpne denne publikasjonen i ny fane eller vindu >>Segmentation of echo cardiographic image sequences using spatio-temporal information
    1999 (engelsk)Inngår i: 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, s. 410-419Kapittel i bok, del av antologi (Fagfellevurdert)
    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.

    sted, utgiver, år, opplag, sider
    Berlin: Springer, 1999
    Serie
    Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349 ; 1679
    Emneord
    medical image computing, computer-assisted intervention, data-driven image segmentation, structural models, image processing, feature detection, surfaces, shape, measurement, image interpretation, spatiotemporal analysis, diffusion tensor analysis, image registration, data fusion, data visualisation, image-guided intervention, robotic systems, biomechanics, simulation
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-49138 (URN)10.1007/10704282_45 (DOI)3-540-66503-X (ISBN)
    Tilgjengelig fra: 2009-10-11 Laget: 2009-10-11 Sist oppdatert: 2018-01-30
    2. Three-dimensional flow characterization using vector pattern matching
    Åpne denne publikasjonen i ny fane eller vindu >>Three-dimensional flow characterization using vector pattern matching
    2003 (engelsk)Inngår i: IEEE Transactions on Visualization and Computer Graphics, ISSN 1077-2626, E-ISSN 1941-0506, Vol. 9, nr 3, s. 313-319Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    This paper describes a novel method for regional characterization of three-dimensional vector fields using a pattern matching approach. Given a three-dimensional vector field, the goal is to automatically locate, identify, and visualize a selected set of classes of structures or features. Rather than analytically defining the properties that must be fulfilled in a region in order to be classified as a specific structure, a set of idealized patterns for each structure type is constructed. Similarity to these patterns is then defined and calculated. Examples of structures of interest include vortices, swirling flow, diverging or converging flow, and parallel flow. Both medical and aerodynamic applications are presented in this paper.

    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-26709 (URN)10.1109/TVCG.2003.1207439 (DOI)11302 (Lokal ID)11302 (Arkivnummer)11302 (OAI)
    Tilgjengelig fra: 2009-10-08 Laget: 2009-10-08 Sist oppdatert: 2017-12-13
    3. Kinematics of the heart: strain-rate imaging from time-resolved three-dimensional phase contrast MRI
    Åpne denne publikasjonen i ny fane eller vindu >>Kinematics of the heart: strain-rate imaging from time-resolved three-dimensional phase contrast MRI
    Vise andre…
    2002 (engelsk)Inngår i: IEEE Transactions on Medical Imaging, ISSN 0278-0062, E-ISSN 1558-254X, Vol. 21, nr 9, s. 1105-1109Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    A four-dimensional mapping (three spatial dimensions + time) of myocardial strain-rate would help to describe the mechanical properties of the myocardium, which affect important physiological factors such as the pumping performance of the ventricles. Strain-rate represents the local instantaneous deformation of the myocardium and can be calculated from the spatial gradients of the velocity field. Strain-rate has previously been calculated using one-dimensional (ultrasound) or two-dimensional (2-D) magnetic resonance imaging techniques. However, this assumes that myocardial motion only occurs in one direction or in one plane, respectively. This paper presents a method for calculation of the time-resolved three-dimensional (3-D) strain-rate tensor using velocity vector information in a 3-D spatial grid during the whole cardiac cycle. The strain-rate tensor provides full information of both magnitude and direction of the instantaneous deformation of the myocardium. A method for visualization of the full 3-D tensor is also suggested. The tensors are visualized using ellipsoids, which display the principal directions of strain-rate and the ratio between strain-rate magnitude in each direction. The presented method reveals the principal strain-rate directions without a priori knowledge of myocardial motion directions.

    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-26711 (URN)10.1109/TMI.2002.804431 (DOI)11305 (Lokal ID)11305 (Arkivnummer)11305 (OAI)
    Tilgjengelig fra: 2009-10-08 Laget: 2009-10-08 Sist oppdatert: 2018-07-03
    4. Time resolved three-dimensional segmentation of the left ventricle in multimodality cardiac imaging
    Åpne denne publikasjonen i ny fane eller vindu >>Time resolved three-dimensional segmentation of the left ventricle in multimodality cardiac imaging
    Vise andre…
    (engelsk)Manuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    We propose a robust approach for multimodality segmentation of the cardiac left ventricle. The method is based on the concept of deformable models, but extended with an enhanced and fast edge detection scheme that includes temporal information, and anatomical a priori information. The algorithm is implemented with a fast numeric scheme for solving energy minimization, and efficient filter nets for fast edge detection. This allows clinically applicable time for a whole time resolved 3D cardiac data set to be acheived on a standard desktop computer. The algorithm is validated on images acquired using MRI Gradient echo, MRl (SSFP) images, and Cardiac CT, and tested for feasibility with three other imaging modalities, including gated blood pool SPECT, echocardiography and late enhancement MRL.

    Emneord
    Image Segmentation, Deformable models, Left Ventricle, 3D, time resolved, edge detection
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-86175 (URN)
    Tilgjengelig fra: 2012-12-10 Laget: 2012-12-10 Sist oppdatert: 2016-03-14
    5. Flow quantification from time resolved three dimensional phase contrast MRI
    Åpne denne publikasjonen i ny fane eller vindu >>Flow quantification from time resolved three dimensional phase contrast MRI
    (engelsk)Manuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    This paper presents novel techniques for deriving meaningful quantitative parameters from three dimensional velocity measurements. By shifting perspective from the Eulerian grid of measured velocities to a Lagrange perspective that follows flow using particle traces, we are able to divide flow into different groups based on their behavior. Parameters from each group can then be extracted and quantified. The applicability of the method is demonstrated by extracting parameters of diastolic flow in the human left ventricle.

    Emneord
    Flow quantification, velocity measurements, particle trace, left ventricle
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-86176 (URN)
    Tilgjengelig fra: 2012-12-10 Laget: 2012-12-10 Sist oppdatert: 2016-03-14
  • 8.
    Heiberg, Einar
    et al.
    Linköpings universitet, Institutionen för medicin och vård, Centrum för medicinsk bildvetenskap och visualisering. Linköpings universitet, Hälsouniversitetet.
    Bolger, Ann F.
    Department of Medicine, University of California, San Francisco, USA.
    Karlsson, Matts
    Linköpings universitet, Institutionen för medicin och vård. Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Hälsouniversitetet.
    Flow quantification from time resolved three dimensional phase contrast MRIManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    This paper presents novel techniques for deriving meaningful quantitative parameters from three dimensional velocity measurements. By shifting perspective from the Eulerian grid of measured velocities to a Lagrange perspective that follows flow using particle traces, we are able to divide flow into different groups based on their behavior. Parameters from each group can then be extracted and quantified. The applicability of the method is demonstrated by extracting parameters of diastolic flow in the human left ventricle.

  • 9.
    Heiberg, Einar
    et al.
    Linköpings universitet, Institutionen för medicin och vård, Centrum för medicinsk bildvetenskap och visualisering. Linköpings universitet, Hälsouniversitetet.
    Wigström, Lars
    Linköpings universitet, Institutionen för medicin och vård, Centrum för medicinsk bildvetenskap och visualisering. Linköpings universitet, Hälsouniversitetet.
    Carlsson, Marcus
    Department of Clinical Physiology, Lund University, Sweden.
    Bolger, Ann F.
    Department of Medicine/Cardiology, University of California, San Francisco, USA.
    Karlsson, Matts
    Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Institutionen för medicin och vård, Centrum för medicinsk bildvetenskap och visualisering. Linköpings universitet, Hälsouniversitetet.
    Time resolved three-dimensional segmentation of the left ventricle in multimodality cardiac imagingManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    We propose a robust approach for multimodality segmentation of the cardiac left ventricle. The method is based on the concept of deformable models, but extended with an enhanced and fast edge detection scheme that includes temporal information, and anatomical a priori information. The algorithm is implemented with a fast numeric scheme for solving energy minimization, and efficient filter nets for fast edge detection. This allows clinically applicable time for a whole time resolved 3D cardiac data set to be acheived on a standard desktop computer. The algorithm is validated on images acquired using MRI Gradient echo, MRl (SSFP) images, and Cardiac CT, and tested for feasibility with three other imaging modalities, including gated blood pool SPECT, echocardiography and late enhancement MRL.

  • 10.
    Ragnehed, Mattias
    et al.
    Linköpings universitet, Institutionen för medicin och vård, Radiologi. Linköpings universitet, Hälsouniversitetet.
    Engström, Maria
    Linköpings universitet, Institutionen för medicin och vård, Centrum för medicinsk bildvetenskap och visualisering. Linköpings universitet, Hälsouniversitetet.
    Knutsson, Hans
    Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Hälsouniversitetet.
    Lundberg, Peter
    Linköpings universitet, Institutionen för medicin och vård, Medicinsk radiofysik. Linköpings universitet, Hälsouniversitetet.
    Söderfeldt, Birgitta
    Linköpings universitet, Institutionen för nervsystem och rörelseorgan. Linköpings universitet, Hälsouniversitetet.
    Performance of canonical correlation analysis in language tests by functional MRIManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    In this paper a new method based on constraitwd canonical correlation analysis (CCA) for the analysis of fMRI data is evaluated. In particular the method benefits from a powerful way of choosing temporal basis functions in additiou to an adaptive spatial filtering scheme. A modified receiver operating characteristic (ROC) method was used to quantify the results and to compare it with traditionally used statistics in an objective way. The evaluation was performed using real fMRI data form a language test. It was shown that the CCA based method offers a significant gain in detection power.

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