title: Reproducibility of myocardial strain and left ventricular twist measured using complementary spatial modulation of magnetization.
abstract: OBJECTIVE
  To establish the reproducibility of complementary spatial modulation of magnetization (CSPAMM) tagged cardiovascular MR (CMR) data in normal volunteers.
  
  
  METHODS
  Twelve healthy volunteers underwent CMR studies on two separate occasions using an identical CSPAMM pulse sequence with images acquired in three short axis slices. Data were analyzed by two independent observers using harmonic phase analysis (HARP). Lagrangian circumferential and radial strain, rotation, and left ventricular twist were calculated.
  
  
  RESULTS
  The intraobserver reproducibility of circumferential strain (CoV [coefficient of variation] 1.5-4.3%) and LV twist (CoV 1.2-4.4%) was better than radial strain (CoV 10.6-14.8%). For interobserver reproducibility, circumferential strain (CoV 3.5-6.2%) and LV twist (CoV 3.5-7.2%) were more reproducible than radial strain (CoV 11.8-21.8%). Interstudy reproducibility of circumferential strain (CoV 3.7-5.5%) and LV twist (CoV 9.8-12.2%) were good but radial strain (CoV 13.8-23.4%) but showed poorer interstudy reproducibility. Sample size calculations suggested 20 or fewer subjects are needed to detect a 10% change in circumferential strain (power 90%; α error 0.05), whereas for twist, 66 subjects would be required.
  
  
  CONCLUSIONS
  In normal volunteers, the intraobserver, interobserver, and interstudy reproducibility of circumferential strain and LV twist measured from CSPAMM tagged CMR data are good, but are less so for radial strain.
authors.affiliation: Leeds General Infirmary, Leeds, United Kingdom.
authors.forename: Peter P
authors.initials: PP
authors.lastname: Swoboda
authors.forename: Abdulghani
authors.initials: A
authors.lastname: Larghat
authors.forename: Arshad
authors.initials: A
authors.lastname: Zaman
authors.forename: Timothy A
authors.initials: TA
authors.lastname: Fairbairn
authors.forename: Manish
authors.initials: M
authors.lastname: Motwani
authors.forename: John P
authors.initials: JP
authors.lastname: Greenwood
authors.forename: Sven
authors.initials: S
authors.lastname: Plein
mesh_terms: D000328:Adult; D000465:Algorithms; D055119:Elastic Modulus / Q000502:physiology; D054459:Elasticity Imaging Techniques / Q000379:methods*; D005260:Female; D006352:Heart Ventricles / Q000033:anatomy & histology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D012016:Reference Values; D015203:Reproducibility of Results; D012399:Rotation; D012680:Sensitivity and Specificity; D013718:Tensile Strength / Q000502:physiology; D016277:Ventricular Function, Left / Q000502:physiology*
keywords: CSPAMM; reproducibility; tagging