title: Intramural mechanics in hypertrophic cardiomyopathy: functional mapping with strain-rate MR imaging.
abstract: OBJECTIVE
  To characterize systolic and diastolic intramural mechanics in hypertrophic cardiomyopathy (HCM) with a new metric of contractile activity.
  
  
  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).
  
  
  CONCLUSIONS
  SR characterization may provide an objective measure of disease course in HCM.
authors.affiliation: MGH-NMR Center, Department of Radiology, Massachusetts General Hospital, Charlestown 02129, USA.
authors.forename: G M
authors.initials: GM
authors.lastname: Beache
authors.forename: V J
authors.initials: VJ
authors.lastname: Wedeen
authors.forename: R M
authors.initials: RM
authors.lastname: Weisskoff
authors.forename: P T
authors.initials: PT
authors.lastname: O'Gara
authors.forename: B P
authors.initials: BP
authors.lastname: Poncelet
authors.forename: D A
authors.initials: DA
authors.lastname: Chesler
authors.forename: T J
authors.initials: TJ
authors.lastname: Brady
authors.forename: B R
authors.initials: BR
authors.lastname: Rosen
authors.forename: R E
authors.initials: RE
authors.lastname: Dinsmore
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002312:Cardiomyopathy, Hypertrophic / Q000175:diagnosis*; D002648:Child; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged