title: Effect of papillary muscles and trabeculae on left ventricular measurement using cardiovascular magnetic resonance imaging in patients with hypertrophic cardiomyopathy.
abstract: OBJECTIVE
  To evaluate the influence of papillary muscles and trabeculae on left ventricular (LV) cardiovascular magnetic resonance (CMR) analysis using three methods of cavity delineation (classic or modified inclusion methods, and the exclusion method) in patients with hypertrophic cardiomyopathy (HCM).
  
  
  METHODS
  This retrospective study included 20 consecutive HCM patients who underwent 1.5-T CMR imaging with short-axis cine stacks of the entire LV. LV measurements were performed using three different methods of manual cavity delineation of the endocardial and epicardial contours: method A, presumed endocardial boundary as seen on short-axis cine images; method B, including solely the cavity and closely adjacent trabeculae; or method C, excluding papillary muscles and trabeculae. Ascending aorta forward flow was measured as reference for LV-stroke volume (SV). Interobserver reproducibility was assessed using intraclass correlation coefficients.
  
  
  RESULTS
  Method A showed larger end-diastole and end-systole volumes (largest percentage differences of 25% and 68%, respectively, p < 0.05), compared with method C. The ejection fraction was 55.7 ± 6.9% for method A, 68.6 ± 8.4% for B, and 71.7 ± 7.0% for C (p < 0.001). Mean mass was also significantly different: 164.6 ± 47.4 g for A, 176.5 ± 50.5 g for B, and 199.6 ± 53.2 g for C (p < 0.001). LV-SV error was largest with method B (p < 0.001). No difference in interobserver agreement was observed (p > 0.05).
  
  
  CONCLUSIONS
  In HCM patients, LV measurements are strikingly different dependent on whether papillary muscles and trabeculae are included or excluded. Therefore, a consistent method of LV cavity delineation may be crucial during longitudinal follow-up to avoid misinterpretation and erroneous clinical decision-making.
authors.affiliation: Department of Radiology, Cardiovascular Division, Seoul National University Hospital, Seoul 110-744, Korea.
authors.forename: Eun-Ah
authors.initials: EA
authors.lastname: Park
authors.affiliation: Department of Radiology, Cardiovascular Division, Seoul National University Hospital, Seoul 110-744, Korea.
authors.forename: Whal
authors.initials: W
authors.lastname: Lee
authors.affiliation: Department of Internal Medicine, Cardiovascular Division, Seoul National University Hospital, Seoul 110-744, Korea.
authors.forename: Hyung-Kwan
authors.initials: HK
authors.lastname: Kim
authors.affiliation: Department of Radiology, Cardiovascular Division, Seoul National University Hospital, Seoul 110-744, Korea.
authors.forename: Jin Wook
authors.initials: JW
authors.lastname: Chung
mesh_terms: D000328:Adult; D000368:Aged; D002312:Cardiomyopathy, Hypertrophic / Q000473:pathology*; D005260:Female; D006352:Heart Ventricles / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine; D008297:Male; D008875:Middle Aged; D010210:Papillary Muscles / Q000503:physiopathology*; D011859:Radiography; D012189:Retrospective Studies; D013318:Stroke Volume / Q000502:physiology; D013599:Systole / Q000502:physiology
keywords: Cardiomyopathy, hypertrophic; Magnetic resonance imaging, cine; Measurement accuracy, dimensional; Papillary muscles; Ventricular function, left