title: Comparison of strain measurement from multimodality tissue tracking with strain-encoding MRI and harmonic phase MRI in pulmonary hypertension.
abstract: BACKGROUND
  Pixel-based multimodality tissue tracking (MTT) is a new noninvasive method for the quantification of cardiac deformation from cine image of MRI. The aim of this study is to validate bi-ventricular strain measurement by MTT compared to strain-encoding (SENC) MRI and harmonic phase (HARP) MRI in pulmonary hypertension (PH) patients.
  
  
  METHODS
  In 45 subjects (30 PH patients and 15 normal subjects), RV and LV peak global longitudinal strains (Ell) were measured from long axis 4 chamber view using MTT. LV peak global circumferential strains (Ecc) by MTT were measured from short axis. For validation, RV and LV Ell by MTT were compared to measures by SENC-MRI from short axis, and LV Ecc by MTT was compared to measures by short axis tagged MRI analysis (HARP). Reproducibility of MTT was also determined.
  
  
  RESULTS
  MTT quantified RV Ell correlated closely to those of SENC (r=0.72, p<0.001), with good limits of agreement. LV Ell quantified by MTT showed moderate correlation with SENC (r=0.57, p=0.001), and LV Ecc by MTT also showed moderate correlation with HARP (-16.9±4.1 vs -14.3±3.5, p<0.001 for all, r=0.60, p<0.001). RV Ell negatively correlated with RVEF (r=-0.53, p=0.001) and also positively correlated with mean PAP in PH patients (r=0.60, p=0.001). Strain measurement by MTT showed high reproducibility.
  
  
  CONCLUSIONS
  We demonstrate that MTT is a reproducible tool for quantification of cardiac deformation using cine images in PH patients. Hence, it could serve as a new rapid and comprehensive technique for clinical assessment of regional cardiac function.
authors.affiliation: Division of Cardiology, Johns Hopkins University, Baltimore, MD, USA. Electronic address: yohyama1@jhmi.edu.
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Ohyama
authors.affiliation: Division of Cardiology, Johns Hopkins University, Baltimore, MD, USA. Electronic address: bambale1@jhmi.edu.
authors.forename: Bharath
authors.initials: B
authors.lastname: Ambale-Venkatesh
authors.affiliation: Division of Cardiology, Johns Hopkins University, Baltimore, MD, USA. Electronic address: echamer1@jhmi.edu.
authors.forename: Elzbieta
authors.initials: E
authors.lastname: Chamera
authors.affiliation: Mercy Catholic Medical Center, Philadelphia, PA, USA. Electronic address: mondashehata@gmail.com.
authors.forename: Monda L
authors.initials: ML
authors.lastname: Shehata
authors.affiliation: Division of Radiology, Johns Hopkins University, Baltimore, MD, USA. Electronic address: ccorona1@jhmi.edu.
authors.forename: Celia P
authors.initials: CP
authors.lastname: Corona-Villalobos
authors.affiliation: Division of Radiology, Johns Hopkins University, Baltimore, MD, USA. Electronic address: stefan.zimmerman@jhmi.edu.
authors.forename: Stefan L
authors.initials: SL
authors.lastname: Zimmerman
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Johns Hopkins University, Baltimore, MD, USA. Electronic address: phassou1@jhmi.edu.
authors.forename: Paul M
authors.initials: PM
authors.lastname: Hassoun
authors.affiliation: National Institutes of Health, Bethesda, MD, USA. Electronic address: bluemked@cc.nih.gov.
authors.forename: David A
authors.initials: DA
authors.lastname: Bluemke
authors.affiliation: Division of Cardiology, Johns Hopkins University, Baltimore, MD, USA. Electronic address: jlima@jhmi.edu.
authors.forename: Joao A C
authors.initials: JAC
authors.lastname: Lima
mesh_terms: D005260:Female; D006352:Heart Ventricles / Q000473:pathology* / Q000503:physiopathology; D006801:Humans; D006976:Hypertension, Pulmonary / Q000175:diagnosis* / Q000503:physiopathology; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction / Q000502:physiology*; D015203:Reproducibility of Results; D016278:Ventricular Function, Right / Q000502:physiology*
keywords: Cardiac magnetic resonance; Myocardial strain; Pulmonary hypertension