title: A disproportionate contribution of papillary muscles and trabeculations to total left ventricular mass makes choice of cardiovascular magnetic resonance analysis technique critical in Fabry disease.
abstract: BACKGROUND
  Sphingolipid deposition in Fabry disease causes left ventricular (LV) hypertrophy, of which the accurate assessment is essential. Cardiovascular magnetic resonance (CMR) has been proposed as the gold standard. However, there is debate in the literature as to whether papillary muscles and trabeculations (P&T) should be included in LV mass (LVM).
  
  
  RESULTS
  We examined the accuracy of 2 CMR methods of assessing LVM and LV volumes, including (M inc P&T) or excluding (M ex P&T) P&T, in a cohort of Fabry disease subjects (n = 20) compared to a matched control group (n = 20). Significant differences between the two measurement methods were observed for LV end-diastolic volume, LV end-systolic volume, LVM, and LV ejection fraction (LVEF) in both groups. These differences were significantly greater in the Fabry group compared to controls, except for LVEF. P&T contributed to a greater percentage of LVM in Fabry subjects than controls (20 ± 1% vs 13 ± 2%, p = 0.01). In the control group, both volume-derived methods (M inc P&T or MexP&T) provided accurate SV measurements compared with the internal reference of velocity-encoded aortic flow. In the Fabry group, inclusion of P&T (M inc P&T) resulted in good concordance with phase contrast flow imaging (difference between flow and volume techniques: 1 ± 3 ml, p = 0.7).
  
  
  CONCLUSIONS
  The volumetric contribution of P&T in Fabry disease is markedly increased relative to healthy controls. Failure to account for this results in significant underestimation of LVM and results in misclassification of a proportion of subjects.
authors.affiliation: North Shore Heart Research Group, Kolling Institute of Medical Research, University of Sydney, Sydney, Australia. rebeccakozor@gmail.com.|Department of Cardiology, Royal North Shore Hospital, Sydney, Australia. rebeccakozor@gmail.com.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Kozor
authors.affiliation: Sydney Translational Imaging Laboratory, Sydney Medical School, University of Sydney, Sydney, Australia. fraser.callaghan@sydney.edu.au.
authors.forename: Fraser
authors.initials: F
authors.lastname: Callaghan
authors.affiliation: Department of Genetic Medicine, Westmead Hospital, Sydney, Australia. Michel.Tchan@health.nsw.gov.au.|Discipline of Genetic Medicine, Sydney Medical School, University of Sydney, Sydney, Australia. Michel.Tchan@health.nsw.gov.au.
authors.forename: Michel
authors.initials: M
authors.lastname: Tchan
authors.affiliation: Heart and Lung Institute, The Prince Charles Hospital, Brisbane, Australia. chamiltoncraig@gmail.com.|University of Queensland, Brisbane, Australia. chamiltoncraig@gmail.com.
authors.forename: Christian
authors.initials: C
authors.lastname: Hamilton-Craig
authors.affiliation: North Shore Heart Research Group, Kolling Institute of Medical Research, University of Sydney, Sydney, Australia. gemma.figtree@sydney.edu.au.|Department of Cardiology, Royal North Shore Hospital, Sydney, Australia. gemma.figtree@sydney.edu.au.
authors.forename: Gemma A
authors.initials: GA
authors.lastname: Figtree
authors.affiliation: North Shore Heart Research Group, Kolling Institute of Medical Research, University of Sydney, Sydney, Australia. sgrieve@med.usyd.edu.au.|Sydney Translational Imaging Laboratory, Sydney Medical School, University of Sydney, Sydney, Australia. sgrieve@med.usyd.edu.au.
authors.forename: Stuart M
authors.initials: SM
authors.lastname: Grieve
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D000795:Fabry Disease / Q000175:diagnosis* / Q000473:pathology / Q000503:physiopathology; D006352:Heart Ventricles / Q000473:pathology* / Q000503:physiopathology; D006801:Humans; D017379:Hypertrophy, Left Ventricular / Q000175:diagnosis* / Q000473:pathology / Q000503:physiopathology; D007090:Image Interpretation, Computer-Assisted; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D010210:Papillary Muscles / Q000473:pathology* / Q000503:physiopathology; D011237:Predictive Value of Tests; D011379:Prognosis; D012042:Registries; D015203:Reproducibility of Results; D013318:Stroke Volume; D016277:Ventricular Function, Left; D055815:Young Adult