title: Impact of the papillary muscles on cardiac magnetic resonance image analysis of important left ventricular parameters in hypertrophic cardiomyopathy.
abstract: OBJECTIVE
  The use of cardiac magnetic resonance (CMR) analysis has increased in patients with hypertrophic cardiomyopathy (HCM). Quantification of left ventricular (LV) measures will be affected by the inclusion or exclusion of the papillary muscles as part of the LV mass, but the magnitude of effect and potential consequences are unknown.
  
  
  METHODS
  We performed Cine-CMR in (1) clinical HCM patients (n = 55) and (2) subclinical HCM mutation carriers without hypertrophy (n = 14). Absolute and relative differences in LV ejection fraction (EF) and mass were assessed between algorithms with and without inclusion of the papillary muscles.
  
  
  RESULTS
  Papillary muscle mass in group 1 was 6.6 ± 2.5 g/m(2) and inclusion of the papillary muscles resulted in significant relative increases in LVEF of 4.5 ± 1.8 % and in LV mass of 8.7 ± 2.6 %. For group 2 these figures were 4.0 ± 0.9 g/m(2), 3.8 ± 1.0 % and 9.5 ± 1.8 %, respectively. With a coefficient of variation of 4 %, this 9 % difference in LV mass during CMR follow-up will be considered a change, while in fact the exact same mass may have been assessed according to two different algorithms.
  
  
  CONCLUSIONS
  In clinical HCM patients, CMR quantification of important LV measures is significantly affected by inclusion or exclusion of the papillary muscles. In relative terms, the difference was similar in subjects without hypertrophy. This underscores a general need for a uniform approach in CMR image analysis.
authors.affiliation: Department of Cardiology, Radboud University Medical Centre, Nijmegen, The Netherlands. frank.gommans@radboudumc.nl.
authors.forename: D H F
authors.initials: DH
authors.lastname: Gommans
authors.affiliation: Department of Radiology, Albert Schweitzer Hospital, Dordrecht, The Netherlands.
authors.forename: J
authors.initials: J
authors.lastname: Bakker
authors.affiliation: Department of Cardiology, Radboud University Medical Centre, Nijmegen, The Netherlands.
authors.forename: G E
authors.initials: GE
authors.lastname: Cramer
authors.affiliation: Department of Cardiology, Radboud University Medical Centre, Nijmegen, The Netherlands.
authors.forename: F W A
authors.initials: FW
authors.lastname: Verheugt
authors.affiliation: Department of Cardiology, Radboud University Medical Centre, Nijmegen, The Netherlands.
authors.forename: M A
authors.initials: MA
authors.lastname: Brouwer
authors.affiliation: Department of Cardiology, Albert Schweitzer Hospital, Dordrecht, The Netherlands.
authors.forename: M J M
authors.initials: MJ
authors.lastname: Kofflard
keywords: CMR; Cardiac magnetic resonance; Hypertrophic cardiomyopathy; Papillary muscles