title: Ex vivo cardiovascular magnetic resonance measurements of right and left ventricular mass compared with direct mass measurement in excised hearts after transplantation: a first human SSFP comparison.
abstract: BACKGROUND
  CMR is considered the 'gold standard' for non-invasive LV and RV mass quantitation. This information is solely based on gradient-recalled echo (GRE) sequences while contrast dependent on intrinsic T1/T2 characteristics potentially offers superior image contrast between blood and myocardium. This study aims, for the first time in humans, to validate the SSFP approach using explanted hearts obtained from heart transplant recipients. Our objective is establish the correlation between and to validate steady-state free precession (SSFP) derived LV and RV mass vs. autopsy mass of hearts from cardiac transplants patients.
  
  
  METHODS
  Over three-years, 58 explanted cardiomyopathy hearts were obtained immediately upon orthotopic heart transplantation from the OR. They were quickly cleaned, prepared and suspended in a saline-filled container and scanned ex vivo via SSFP-SA slices to define LV/RV mass. Using an automatic thresholding program, segmentation was achieved in combination with manual trimming (ATMT) of extraneous tissue incorporating 3D cardiac modeling performed by independent and blinded readers. The explanted hearts were then dissected with the ventricles surgically separated at the interventricular septum. Weights of the total heart not excluding papillary and trabecular myocardium, LV and RV were measured via high-fidelity scale. Linear regression and Bland-Altman plots were used to analyze the data. The intra-class correlation coefficient was used to assess intra-observer reliability.
  
  
  RESULTS
  Of the total of 58 explanted hearts, 3 (6%) were excluded due to poor image quality leaving 55 patients (94%) for the final analysis. Significant positive correlations were found between total 3D CMR mass (450 ± 111 g) and total pathology mass (445 ± 116 g; r = 0.99, p < 0.001) as well as 3D CMR measured LV mass (301 ± 93 g) and the pathology measured LV mass (313 ± 96 g; r = 0.95, p < 0.001). Strong positive correlations were demonstrated between the 3D CMR measured RV mass (149 ± 46 g) and the pathology measured RV mass (128 ± 40 g; r = 0.76, p < 0.001). The mean bias between 3D-CMR and pathology measures for total mass, LV mass and RV mass were: 3.0 g, -16 g and 19 g, respectively.
  
  
  CONCLUSIONS
  SSFP-CMR accurately determines total myocardial, LV and RV mass as compared to pathology weighed explanted hearts despite variable surgical removal of instrumentation (left and right ventricular assist devices, AICD and often apical core removals). Thus, this becomes the first-ever human CMR confirmation for SSFP now validating the distinction of 'gold standard'.
authors.affiliation: Gerald McGinnis Cardiovascular Institute, Allegheny General Hospital, Pittsburgh, PA, USA. nfarber@gmail.com.
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Farber
authors.affiliation: Gerald McGinnis Cardiovascular Institute, Allegheny General Hospital, Pittsburgh, PA, USA. beenasahadev@comcast.net.
authors.forename: Sahadev T
authors.initials: ST
authors.lastname: Reddy
authors.affiliation: Gerald McGinnis Cardiovascular Institute, Allegheny General Hospital, Pittsburgh, PA, USA. MDOYLE@wpahs.org.
authors.forename: Mark
authors.initials: M
authors.lastname: Doyle
authors.affiliation: Gerald McGinnis Cardiovascular Institute, Allegheny General Hospital, Pittsburgh, PA, USA. GRAYARAO@wpahs.org.
authors.forename: Geetha
authors.initials: G
authors.lastname: Rayarao
authors.affiliation: Gerald McGinnis Cardiovascular Institute, Allegheny General Hospital, Pittsburgh, PA, USA. dthomps1@wpahs.org.
authors.forename: Diane V
authors.initials: DV
authors.lastname: Thompson
authors.affiliation: Department of Pathology, Allegheny General Hospital, Pittsburgh, PA, USA. POLSON@wpahs.org.
authors.forename: Peter
authors.initials: P
authors.lastname: Olson
authors.affiliation: Department of Pathology, Allegheny General Hospital, Pittsburgh, PA, USA. JGLASS@wpahs.org.
authors.forename: Jerry
authors.initials: J
authors.lastname: Glass
authors.affiliation: Gerald McGinnis Cardiovascular Institute, Allegheny General Hospital, Pittsburgh, PA, USA. RWILLIA2@wpahs.org.
authors.forename: Ronald B
authors.initials: RB
authors.lastname: Williams
authors.affiliation: Gerald McGinnis Cardiovascular Institute, Allegheny General Hospital, Pittsburgh, PA, USA. JYAMROZI@wpahs.org.
authors.forename: June A
authors.initials: JA
authors.lastname: Yamrozik
authors.affiliation: Gerald McGinnis Cardiovascular Institute, Allegheny General Hospital, Pittsburgh, PA, USA. SMURALI@wpahs.org.
authors.forename: Srinivas
authors.initials: S
authors.lastname: Murali
authors.affiliation: Gerald McGinnis Cardiovascular Institute, Allegheny General Hospital, Pittsburgh, PA, USA. RBIEDERM@wpahs.org.
authors.forename: Robert Ww
authors.initials: RW
authors.lastname: Biederman
mesh_terms: D000328:Adult; D000368:Aged; D009202:Cardiomyopathies / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D005260:Female; D016027:Heart Transplantation; D006352:Heart Ventricles / Q000473:pathology* / Q000601:surgery; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D016014:Linear Models; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D009929:Organ Size; D011237:Predictive Value of Tests; D011446:Prospective Studies; D015203:Reproducibility of Results; D055815:Young Adult