Radiology, Vol 197, 117-124, Copyright © 1995 by Radiological Society of North America
Intramural mechanics in hypertrophic cardiomyopathy: functional mapping with strain-rate MR imaging
GM Beache, VJ Wedeen, RM Weisskoff, PT O'Gara, BP Poncelet, DA Chesler, TJ Brady, BR Rosen and RE Dinsmore
MGH-NMR Center, Department of Radiology, Massachusetts General Hospital, Charlestown 02129, USA.
PURPOSE: To characterize systolic and diastolic intramural mechanics in
hypertrophic cardiomyopathy (HCM) with a new metric of contractile
activity. MATERIALS AND METHODS: Eleven healthy subjects and eight patients
with HCM underwent velocity-encoded echo-planar magnetic resonance (MR)
imaging (6-8-frame gated breath-hold movies, 3 x 3-mm resolution). A scalar
strain rate (SR) parameter was compared with wall thickness and symptoms.
RESULTS: The normal pattern of SR included regional uniformity, a
monotonically increasing subepicardial to subendocardial gradient, and
minimum transmural shear rate. In HCM, heterogeneity of SRs increased in
diastole. Regional diastolic SR correlated with regional wall thickness (r
= .785, P = .0001). Interobserver global SR assignment agreed in seven of
eight patients. All four patients with New York Heart Association class 1
disease had a low global SR deficit score, whereas three of four patients
with class 2 or 3 disease had a high SR deficit score (Spearman r = .775, P
= .187). CONCLUSION: SR characterization may provide an objective measure
of disease course in HCM.
