Validation of tagging with MR imaging to estimate material deformation.

Young, Alistair A.; Axel, Leon; Dougherty, Lawrence; Bogen, Daniel K.; Parenteau, C S

doi:10.1148/radiology.188.1.8511281

Cited by 167 publications

(100 citation statements)

References 17 publications

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“…In previous work, Moore et al (26) studied the precision of strains computed by tracking the intersection of radial tags with myocardial contours, and Young et al (27) studied the precision of two-dimensional strains computed using finite element analysis in a deforming phantom. Although both of these studies quantified strain estimate precision, they did not quantify the spatial resolution of the estimates or study the variation in spatial resolution as a function of tag separation and the number of tag plane angles.…”

Section: • Discussionmentioning

confidence: 99%

Model‐free reconstruction of three‐dimensional myocardial strain from planar tagged MR images

Denney

McVeigh

1997

Magnetic Resonance Imaging

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A technique is presented for reconstructing a three-dimensional myocardial strain map from a set of parallel-tagged MR images. Radial strains were reconstructed from in vivo data from an anesthetized dog with values between .05 and .1 with a precision of ± .003 for a tag detection accuracy of .1 mm and a tag spacing of 2.5 mm. The reconstruction spatial resolution was demonstrated by reconstructing a localized displacement abnormality. In the circumferential direction, the abnormality that resulted in 5O% displacement attenuation had a full width at half maximum of 5.4 ± .4 mm (mean ± SD). Graphs are presented showing the relationship between the size of an abnormality and the ability of the method to reconstruct that abnormality. The combination of high resolution parallel-tagged MR images and the model-free, coordinate system-free strain reconstruction technique presented in this paper is capable of producing accurate, high resolution strain maps of the myocardium. KeywordsCardiac MRI; Left ventricle; Cardiac mechanics; Spatial resolution Recent developments in MR tagging (1-9) make it possible to noninvasively measure the threedimensional motion of the heart wall. In tagged images, the myocardium appears with a spatially encoded pattern that moves with the tissue and can be analyzed to reconstruct the motion of the myocardium and measures of local contractile performance such as strain. Precise, quantitative measurements of myocardial function (strain) may allow clinicians to detect ischemia during stress testing with lower doses of inotropic agents. Also, the detection of functional recovery in stunned myocardium during low dose dobutamine infusion may be used to detect viable myocardium (10)(11)(12)(13)(14); this requires a technique that is very sensitive to small changes in myocardial strain. In this paper, we present a method for reconstructing a three-dimensional strain field of the left ventricle (LV) from a collection of tagged MR images.O'Dell et al (8) presented a three-dimensional strain reconstruction algorithm based on a prolate spheroidal basis function displacement model. This approach produces excellent results at the midwall, but careful preprocessing is required to get the heart in the correct coordinate system for reconstruction because the coordinate system foci and axes are critical to the reconstruction accuracy. Young et al (7,15) and Moulton et al (16) have developed three-dimensional strain reconstruction schemes based on a 16-element mesh and a piece-wise polynomial displacementCorrespondence to: Thomas S. Denney, Jr.. In this paper, we present a new model-free algorithm for reconstructing three-dimensional strain based on the discrete approach of Denney and Prince (9). The discrete model-free (DMF) algorithm decomposes the myocardial volume into a finely spaced mesh of points and reconstructs a high resolution three-dimensional displacement field using finite difference analysis and a smoothness constraint that minimizes the spatial variation of displacement across the myoc...

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Section: • Discussionmentioning

confidence: 99%

Model‐free reconstruction of three‐dimensional myocardial strain from planar tagged MR images

Denney

McVeigh

1997

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%

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.…”

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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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Validation of tagging with MR imaging to estimate material deformation.

Cited by 167 publications

References 17 publications

Model‐free reconstruction of three‐dimensional myocardial strain from planar tagged MR images

Model‐free reconstruction of three‐dimensional myocardial strain from planar tagged MR images

Mechanics of the Single Left Ventricle

DENSE: Displacement Encoding with Stimulated Echoes in Cardiac Functional MRI

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