Two-dimensional left ventricular deformation during systole using magnetic resonance imaging with spatial modulation of magnetization.

Young, Alistair A.; Imai, Hitoshi; Chang, Cheng-Ning; Axel, Leon

doi:10.1161/01.cir.89.2.740

Cited by 173 publications

(98 citation statements)

References 27 publications

(7 reference statements)

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“…Generally, the shortening of the longitudinal (base-apex) axis is approximately 20 mm in normal subjects (10). In addition, regional heterogeneity of LV longitudinal shortening has been shown in normal volunteers (11)(12)(13) and in patients with heart disease (14). In the experiment, our results also demonstrated that the longitudinal shortening of LV myocardium was greater in posterior and lateral walls and less in anterior and septal walls.…”

Section: Discussionsupporting

confidence: 68%

Correction of left ventricular wall thickening from short‐axis cine MRI for basal‐descent through‐plane motion

Chai

Chen

et al. 2011

Magnetic Resonance Imaging

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Purpose: To solve the problem of the basal descent movement in quantification of the regional left ventricular (LV) myocardial wall thickness (WTh) and wall thickening (%WT) in short-axis (SA) cine MRI for effectively assessing the regional wall motion of LV myocardium.Materials and Methods: LV long-axis tagged MRI and SA cine MRI were performed to calculate the longitudinal translation and circumferential WTh of LV myocardium in eight normal volunteers. The new SA end-systolic thickness (EST) data were reconstructed from the original EST data, based on the quantified longitudinal translation of LV myocardium. Results:The mean %WT of six segments in the basal section after correction was significantly different from that before correction in both intra-and inter-operator experiments. The polar map also showed the significant improvement of the variability of regional %WT and lack of quantification of %WT in the most basal SA slices after correction. Conclusion:The proposed technique demonstrated an important advantage to calculate the %WT in the most basal SA myocardial tissue, which was considered difficult to be achieved using cine MRI. THE SHORT-AXIS (SA) cardiac imaging method has been routinely performed for qualitative or quantitative evaluation of regional left ventricular (LV) function (1-4), however, two potential sources of error make it difficult to precisely measure the LV functional parameters. First, the cross-sectional planes of SA images not strictly perpendicular to the myocardial wall of the left ventricle, especially in the areas near the apex. This problem has been solved by implementing a three-dimensional (3D) approach to calculating wall thickness (WTh) perpendicular to the LV myocardial wall at the different cardiac phases (5). Usually the 3D elemental approach has been applied for detail measurement of the WTh toward the apex. Second, an important phenomenon in the dynamics of cardiac contraction is basal descent during systole. In SA cardiac imaging, the most basal image planes covering the upper part of the left ventricle at enddiastole (ED) do not show the upper part of the left ventricle at end-systole (ES), but rather part of the left atrium or valvular area. Generally, only the planes including the LV myocardium at ED and ES have been quantitatively analyzed, and those most basal SA slices not covering the left ventricle at ES have been excluded.In evaluating the LV volume parameters with cine MRI, Marcus et al found significant differences between the values with and without inclusion of the most basal slices and suggested using more SA images for complete LV coverage (6). In assessing the regional myocardial WTh and wall thickening (%WT), the problems of the basal-descent movement were more complicated because of the through-plane movement during systole. The myocardium at ES was not in the same position as at end-systole in the same imaging plane. This makes it impossible to measure the wall thickness of the exact portion of LV

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Section: Discussionsupporting

confidence: 68%

Correction of left ventricular wall thickening from short‐axis cine MRI for basal‐descent through‐plane motion

Chai

Chen

et al. 2011

Magnetic Resonance Imaging

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“…The regional deformations of the myocardium were then characterized by using homogeneous finite strain analysis on the deforming triangles 6,17,18,24 -27 with the strain software module of VIDA. 21 This methodology has been validated in a phantom 14 and used in vivo by Young et al 27 These studies demonstrated that homogeneous strain analysis produced unbiased estimates of the principal strains, principal angles, and orientations of the principal axes.…”

Section: Image and Data Analysismentioning

confidence: 99%

“…17 Briefly, Delaunay triangulation of the tagged intersections was used to compute uniform triangles across the wall. 22,23 Continuum mechanics mathematics, which characterized the complex deformation patterns of the myocardium, 25 has been described and used by us 6,17,18 and others, 27 by using homogeneous finite strains to characterize 2-dimensional shape changes of the magnetically tagged grids. As we have noted, this approach assumed that deformations within each triangle relative to end-diastole were locally homogeneous (Figure 1).…”

Section: Homogeneous Finite Strain Analysismentioning

confidence: 99%

Mechanics of the Single Left Ventricle

et al. 1998

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Background-Left ventricular (LV) effects on right ventricular (RV) function are well known. Less is understood about the effect of the RV on systemic LV mechanics. To determine this interaction, we compared systemic LVs with and without an RV mechanically coupled to them. Methods and Results-MR myocardial tagging was used to examine 18 subjects with systemic LVs: 10 with functional single LVs (SLV) and 8 normal subjects (NL). Tracking the systolic motion of the intersecting stripes were used to determine regional twist and radial motion. Finite strain analysis was applied to derive principal strains at the atrioventricular valve (AVV) and apical short-axis levels and in 4 anatomic wall regions. Similar E 1 (circumferential shortening) strain and heterogeneity of strain were noted between SLV and NL except in the septal wall. At the septal wall, NL displayed greater absolute strain (AVVϭϪ0.16Ϯ0.02, apexϭϪ0.17Ϯ0.02) and less heterogeneity of strain than SLV (AVVϭϪ0.12Ϯ0.02, apexϭϪ0.13Ϯ0.02). Similar E 2 (wall thickening) strain and heterogeneity of strain were also noted between SLV and NL except again at the septal wall. At the septal wall, SLV displayed greater absolute E 2 strain (AVVϭ0.17Ϯ0.08, apexϭ0.19Ϯ0.09) and less heterogeneity of strain than NL (AVVϭ0.07Ϯ0.07, apexϭ0.05Ϯ0.05). SLV twisted significantly less counterclockwise than NL in 6 of 8 wall regions and actually twisted clockwise at the AVV lateral wall. Although there was no significant difference between groups in radial wall motion, the septal and inferior walls of SLV demonstrated significantly less radial motion compared with other SLV walls. Conclusions-A major influence of the RV on systemic LV strain and radial motion occurs in the septal wall, whereas absence of the RV causes marked differences in LV twist. These findings may yield clues to the long-term functioning of the SLV and be useful in determining strategies for RV augmentation of LV function. (Circulation. 1998;98:330-338.)

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“…Both approaches are easily applicable on standard clinical scanners. Data acquired with tagging provide information with respect to muscle deformation (2,3,(9)(10)(11)(12)(13)(14)(15)(16). While easy to visualize and implement, tagging methods suffer from low spatial resolution.…”

mentioning

confidence: 99%

DENSE: Displacement Encoding with Stimulated Echoes in Cardiac Functional MRI

Aletras

Ding

Balaban

et al. 1999

Journal of Magnetic Resonance

453

424

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Displacement encoding with stimulated echoes (DENSE) was developed for high-resolution myocardial displacement mapping. Pixel phase is modulated by myocardial displacement and data spatial resolution is limited only by pixel size. 2D displacement vector maps were generated for the systolic action in canines with 0.94 × 1.9 mm nominal in-plane resolution and 2.3 mm/π displacement encoding. A radial strain of 0.208 was measured across the free left ventricular wall over 105 ms during systole. DENSE displacement maps require small first-order gradient moments for encoding. DENSE magnitude images exhibit black-blood contrast which allows for better myocardial definition and reduced motion-related artifacts.

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Two-dimensional left ventricular deformation during systole using magnetic resonance imaging with spatial modulation of magnetization.

Abstract: Consistent regional variations in deformation are seen in the normal human heart. Displacement and maximum shortening strains are well characterized with two-dimensional magnetic resonance tagging; however, higher-resolution images will be required to study transmural variations.

Cited by 173 publications

References 27 publications

Correction of left ventricular wall thickening from short‐axis cine MRI for basal‐descent through‐plane motion

Correction of left ventricular wall thickening from short‐axis cine MRI for basal‐descent through‐plane motion

Mechanics of the Single Left Ventricle

DENSE: Displacement Encoding with Stimulated Echoes in Cardiac Functional MRI

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