title: Off-resonance insensitive complementary SPAtial Modulation of Magnetization (ORI-CSPAMM) for quantification of left ventricular twist.
abstract: OBJECTIVE
  To evaluate Off Resonance Insensitive Complementary SPAtial Modulation of Magnetization (ORI-CSPAMM) and Fourier Analysis of STimulated echoes (FAST) for the quantification of left ventricular (LV) systolic and diastolic function and compare it with the previously validated FAST+SPAMM technique.
  
  
  METHODS
  LV short-axis tagged images were acquired with ORI-CSPAMM and SPAMM in healthy volunteers (n = 13). The FAST method was used to automatically estimate LV systolic and diastolic twist parameters from rotation of the stimulated echo and stimulated anti-echo about the middle of k-space subsequent to ∼3 min of user interaction.
  
  
  RESULTS
  There was no significant difference between measures obtained for FAST+ORI-CSPAMM and FAST+SPAMM for mean peak twist (12.9 ± 3.4° versus 11.9 ± 4.0°; P = 0.4), torsion (3.3 ± 0.9°/cm versus 2.9 ± 1.0°/cm, P = 0.3), circumferential-longitudinal shear angle (9.1 ± 3.0° versus 8.2 ± 3.4°, P = 0.3), twisting rate (79.6 ± 20.2°/s versus 68.2 ± 23.4°/s, P = 0.1), untwisting rate (-117.5 ± 31.4°/s versus -106.6 ± 32.4°/s, P = 0.3), normalized untwisting rate (-9.3 ± 2.0/s versus -9.9 ± 4.4/s, P = 0.7), and time of peak twist (281 ± 18 ms versus 293 ± 25 ms, P = 0.04). FAST+ORI-CSPAMM also provided measures of duration of untwisting (148 ± 21 ms) and the ratio of rapid untwisting to peak twist (0.9 ± 0.3). Bland-Altman analysis of FAST+ORI-CSPAMM and FAST+SPAMM twist data demonstrates excellent agreement with a bias of -0.1° and 95% confidence intervals of (-1.0°, 3.2°).
  
  
  CONCLUSIONS
  FAST+ORI-CSPAMM is a semi-automated method that provides a quick and quantitative assessment of LV systolic and diastolic twist and torsion. ORI-CSPAMM corrects off-resonance accrued during tagging preparation and readout and visibly removes chemical shift from the tagging pattern, which confers greater robustness to the derived quantitative measures.
authors.affiliation: Department of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, California, USA; Biomedical Physics Interdepartmental Program, University of California, Los Angeles, California, USA.
authors.forename: Meral
authors.initials: M
authors.lastname: Reyhan
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Natsuaki
authors.forename: Daniel B
authors.initials: DB
authors.lastname: Ennis
mesh_terms: D000328:Adult; D000465:Algorithms; D055424:Cardiac-Gated Imaging Techniques / Q000379:methods*; D003971:Diastole; D005260:Female; D006352:Heart Ventricles / Q000033:anatomy & histology; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D009200:Myocardial Contraction / Q000502:physiology*; D015203:Reproducibility of Results; D012399:Rotation; D012680:Sensitivity and Specificity; D013599:Systole; D016277:Ventricular Function, Left / Q000502:physiology*
keywords: diastole; left ventricle; off-resonance; tagging; twist