title: Left ventricular twist and shear in patients with primary mitral regurgitation.
abstract: OBJECTIVE
  To evaluate the relationship between left ventricular (LV) twist, shear, and twist-per-volume and the severity of mitral regurgitation (MR). Primary MR is a valvular disorder that induces LV dysfunction. There exist several measures of LV rotational mechanics, but it remains unclear which measure of LV dysfunction best accords with the severity of MR. We hypothesized that LV systolic twist-per-volume slope would decrease with increasing severity of MR because of both decreases in rotational mechanics and increases in stroke volumes.
  
  
  METHODS
  Normal subjects (n = 54), moderate MR patients (n = 29), and severe MR patients (n = 54) were studied. Magnetic resonance imaging (MRI) was performed on a 1.5T scanner and grid-tagged LV images were collected at the LV base and LV apex. Measures of LV rotational mechanics were derived from tagged images using Fourier Analysis of STimulated echoes (FAST).
  
  
  RESULTS
  Peak systolic twist-per-volume slope was significantly different for all pairwise comparisons (P < 0.0001) and compared to normal subjects (-0.14 ± 0.05°/mL) was decreased in moderate MR (-0.12 ± 0.04°/mL) and further decreased in severe MR (-0.07 ± 0.03°/mL).
  
  
  CONCLUSIONS
  Peak systolic twist-per-volume slope significantly decreased with increasing severity of MR and is therefore a suitable quantitative imaging biomarker for LV dysfunction in patients with MR.
authors.affiliation: Biomedical Physics Interdepartmental Program, University of California, Los Angeles, California, USA.|Department of Bioengineering, University of California, Los Angeles, California, USA.
authors.forename: Meral
authors.initials: M
authors.lastname: Reyhan
authors.affiliation: Department of Bioengineering, University of California, Los Angeles, California, USA.|Department of Radiological Sciences, University of California, Los Angeles, California, USA.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Department of Electrical and Computer Engineering, Auburn University, Auburn, Alabama, USA.
authors.forename: Ming
authors.initials: M
authors.lastname: Li
authors.affiliation: Department of Radiological Sciences, University of California, Los Angeles, California, USA.
authors.forename: Hyun J
authors.initials: HJ
authors.lastname: Kim
authors.affiliation: Division of Cardiovascular Disease, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA.|Birmingham VA Medical Center, Birmingham, Alabama, USA.
authors.forename: Himanshu
authors.initials: H
authors.lastname: Gupta
authors.affiliation: Division of Cardiovascular Disease, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA.|Birmingham VA Medical Center, Birmingham, Alabama, USA.
authors.forename: Steven G
authors.initials: SG
authors.lastname: Lloyd
authors.affiliation: Division of Cardiovascular Disease, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA.|Birmingham VA Medical Center, Birmingham, Alabama, USA.
authors.forename: Louis J
authors.initials: LJ
authors.lastname: Dell'Italia
authors.affiliation: Department of Electrical and Computer Engineering, Auburn University, Auburn, Alabama, USA.
authors.forename: Thomas
authors.initials: T
authors.lastname: Denney
authors.affiliation: Biomedical Physics Interdepartmental Program, University of California, Los Angeles, California, USA.|Department of Bioengineering, University of California, Los Angeles, California, USA.|Department of Radiological Sciences, University of California, Los Angeles, California, USA.
authors.forename: Daniel B
authors.initials: DB
authors.lastname: Ennis
mesh_terms: D000465:Algorithms; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D008875:Middle Aged; D008944:Mitral Valve Insufficiency; D015203:Reproducibility of Results; D012399:Rotation; D012680:Sensitivity and Specificity; D033081:Shear Strength; D013318:Stroke Volume; D018487:Ventricular Dysfunction, Left
keywords: left ventricle; mitral regurgitation; shear; torsion; twist