Left ventricular shape-based contractility index

et al. 2008

Med Biol Eng Comput

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It is believed that left ventricular (LV) regional shape is indicative of LV regional function, and cardiac pathologies are often associated with regional alterations in ventricular shape. In this article, we present a set of procedures for evaluating regional LV surface shape from anatomically accurate models reconstructed from cardiac magnetic resonance (MR) images. LV surface curvatures are computed using local surface fitting method, which enables us to assess regional LV shape and its variation. Comparisons are made between normal and diseased hearts. It is illustrated that LV surface curvatures at different regions of the normal heart are higher than those of the diseased heart. Also, the normal heart experiences a larger change in regional curvedness during contraction than the diseased heart. It is believed that with a wide range of dataset being evaluated, this approach will provide a new and efficient way of quantifying LV regional function.

Section: Discussionmentioning

confidence: 73%

Section: Introductionmentioning

confidence: 99%

A curvature-based approach for left ventricular shape analysis from cardiac magnetic resonance imaging

Yeo

et al. 2008

Med Biol Eng Comput

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“…If significant PR is found, cardiac MRI is performed to quantify PR severity and RV function (20). Many studies have shown that MRI is the best and most comprehensive approach to quantify the three dimensional (3-D) ventricular geometry and function (4,25,(47)(48), compared with echocardiography (16,41), ventriculography (14,46), angiography (33), and indicator-dilution methods (10). In patients with demonstrable severe PR and borderline RV function, serial MRI assessment becomes mandatory for timing of pulmonary valve replacement (PVR; Ref.…”

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confidence: 99%

Right ventricular regional wall curvedness and area strain in patients with repaired tetralogy of Fallot

American Journal of Physiology-Heart and Circulatory Physiology

Gobeawan

et al. 2012

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Tan RS, Kassab G. Right ventricular regional wall curvedness and area strain in patients with repaired tetralogy of Fallot. Am J Physiol Heart Circ Physiol 302: H1306 -H1316, 2012. First published December 30, 2011 doi:10.1152/ajpheart.00679.2011.-A quantitative understanding of right ventricular (RV) remodeling in repaired tetralogy of Fallot (rTOF) is crucial for patient management. The objective of this study is to quantify the regional curvatures and area strain based on three-dimensional (3-D) reconstructions of the RV using cardiac magnetic resonance imaging (MRI). Fourteen (14) rTOF patients and nine (9) normal subjects underwent cardiac MRI scan. 3-D RV endocardial surface models were reconstructed from manually delineated contours and correspondence between end-diastole (ED) and end systole (ES) was determined. Regional curvedness (C) and surface area at ED and ES were calculated as well as the area strain. The RV shape and deformation in rTOF patients differed from normal subjects in several respects. Firstly, the curvedness at ED (mean for 13 segments, 0.030 Ϯ 0.0076 vs. 0.029 Ϯ 0.0065 mm Ϫ1 ; P Ͻ 0.05) and ES (mean for 13 segments, 0.040 Ϯ 0.012 vs. 0.034 Ϯ 0.0072 mm Ϫ1 ; P Ͻ 0.001) was decreased by chronic pulmonary regurgitation. Secondly, the surface area increased significantly at ED (mean for 13 segments, 982 Ϯ 192 vs. 1,397 Ϯ 387 mm 2 ; P Ͻ 0.001) and ES (mean for 13 segments, 576 Ϯ 130 vs. 1,012 Ϯ 302 mm 2 ; P Ͻ 0.001). In particular, rTOF patients had significantly larger surface area than that in normal subjects in the free wall but not for the septal wall. Thirdly, area strain was significantly decreased (mean for 13 segments, 56 Ϯ 6 vs. 34 Ϯ 7%; P Ͻ 0.0001) in rTOF patients. Fourthly, there were increases in surface area at ED (5,726 Ϯ 969 vs. 6,605 Ϯ 1,122 mm 2 ; P Ͻ 0.05) and ES (4,280 Ϯ 758 vs. 5,569 Ϯ 1,112 mm 2 ; P Ͻ 0.01) and decrease in area strain (29 Ϯ 8 vs. 18 Ϯ 8%; P Ͻ 0.001) for RV outflow tract. These findings suggest significant geometric and strain differences between rTOF and normal subjects that may help guide therapeutic treatment. magnetic resonance imaging; curvature; right ventricular remodeling; deformation; three-dimensional reconstruction TETRALOGY OF FALLOT (TOF) is the most common cyanotic congenital heart disease (19). The main features include ventricular septum defect, subpulmonary stenosis, and overriding aorta and right ventricular (RV) hypertrophy. Surgical repair is usually performed in early infancy to widen the passage from the RV to the pulmonary artery and close the ventricular septal defect. This ensures separation of oxygen-rich and oxygenpoor blood flows to the proper chambers. Surgical repair of TOF often involves disruption of pulmonary valve integrity that leads to pulmonary regurgitation (PR; Refs. 8, 37). This in turn causes RV dilation (9, 23) and RV outflow tract (RVOT) aneurysm (2-3, 13, 28 -29). The RV dilation is usually tolerated with little or no symptoms during the first two to three decades of age. If left untreated, however, continued...

“…Many studies have shown that MRI is a better and more comprehensive approach to quantify 3-D ventricular structure and function (5,28) than echocardiography (17), ventriculography (16,48), angiography (40), and indicator-dilution (11) methods.…”

mentioning

confidence: 99%

Left ventricular regional wall curvedness and wall stress in patients with ischemic dilated cardiomyopathy

American Journal of Physiology-Heart and Circulatory Physiology

Su²,

Yeo³

et al. 2009

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Geometric remodeling of the left ventricle (LV) after myocardial infarction is associated with changes in myocardial wall stress. The objective of this study was to determine the regional curvatures and wall stress based on three-dimensional (3-D) reconstructions of the LV using MRI. Ten patients with ischemic dilated cardiomyopathy (IDCM) and 10 normal subjects underwent MRI scan. The IDCM patients also underwent delayed gadolinium-enhancement imaging to delineate the extent of myocardial infarct. Regional curvedness, local radii of curvature, and wall thickness were calculated. The percent curvedness change between end diastole and end systole was also calculated. In normal heart, a short- and long-axis two-dimensional analysis showed a 41 +/- 11% and 45 +/- 12% increase of the mean of peak systolic wall stress between basal and apical sections, respectively. However, 3-D analysis showed no significant difference in peak systolic wall stress from basal and apical sections (P = 0.298, ANOVA). LV shape differed between IDCM patients and normal subjects in several ways: LV shape was more spherical (sphericity index = 0.62 +/- 0.08 vs. 0.52 +/- 0.06, P < 0.05), curvedness at end diastole (mean for 16 segments = 0.034 +/- 0.0056 vs. 0.040 +/- 0.0071 mm(-1), P < 0.001) and end systole (mean for 16 segments = 0.037 +/- 0.0068 vs. 0.067 +/- 0.020 mm(-1), P < 0.001) was affected by infarction, and peak systolic wall stress was significantly increased at each segment in IDCM patients. The 3-D quantification of regional wall stress by cardiac MRI provides more precise evaluation of cardiac mechanics. Identification of regional curvedness and wall stresses helps delineate the mechanisms of LV remodeling in IDCM and may help guide therapeutic LV restoration.