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

Thomas S. Denney, Elliot R. McVeigh
1997 Journal of Magnetic Resonance Imaging  
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
more » ... ted 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. 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 (10-14); 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 displacement
doi:10.1002/jmri.1880070506 pmid:9307904 pmcid:PMC2396295 fatcat:au632unkdrcdnmusato3abyp4a