title: Mitral annular shape, size, and motion in normals and in patients with cardiomyopathy: evaluation with computed tomography.
abstract: OBJECTIVE
  To assess prospectively, in healthy subjects and in patients with dilated cardiomyopathy (DCM) and hypertrophic obstructive cardiomyopathy (HOCM), the 3-dimensional (3D) shape, size, and motion of the mitral annulus (MA) using computed tomography (CT).
  
  
  METHODS
  Twenty patients with no cardiac abnormalities (referred to as normals), 15 with DCM, and 15 with HOCM as determined by echocardiography underwent contrast-enhanced, retrospectively electrocardiography (ECG)-gated 64-slice CT of the heart. The MA was manually segmented in 10% steps of the RR interval with dedicated 3D software employing the point-wrap algorithm. The MA shape, area size, change of the MA area, and apicobasal MA motion throughout the cardiac cycle was determined and compared between the groups. Intercommissural distances were measured with CT and compared with findings during surgery in 9 patients undergoing ring annuloplasty.
  
  
  RESULTS
  The MA was nonplanar in all phases and subjects, being largest in diastole and smallest in systole. The MA area was significantly (P < 0.001) larger in patients with DCM (11.5 +/- 4.1 cm/m) as compared with normals (5.5 +/- 0.9 cm/m) and HOCM (4.7 +/- 0.9 cm/m). The change of MA area throughout the cardiac cycle was significantly (P < 0.017) smaller in patients with DCM (12.2 +/- 3.3%/m) as compared with normals (20.0 +/- 7.9%/m) and HOCM (20.5 +/- 7.7%/m). The mean apicobasal motion was significantly (P < 0.017) smaller in patients with DCM (2.2 +/- 1.0 mm/m) as compared with normals (3.6 +/- 0.8 mm/m) and HOCM (2.7 +/- 0.7 mm/m). Intercommissural distances as determined by CT showed a good correlation (r = 0.68, P < 0.05) with intraoperative measurements (mean difference, 0.44 mm; limits of agreement, -2.73-3.62 mm).
  
  
  CONCLUSIONS
  Our study provides in vivo human data on the 3D shape, size, and motion of the MA in healthy subjects. Significant changes in size and motion of the MA were noted in patients with HOCM.
authors.affiliation: Institute of Diagnostic Radiology, University Hospital Zurich, Zurich, Switzerland. hatem.alkadhi@usz.ch
authors.forename: Hatem
authors.initials: H
authors.lastname: Alkadhi
authors.forename: Lotus
authors.initials: L
authors.lastname: Desbiolles
authors.forename: Paul
authors.initials: P
authors.lastname: Stolzmann
authors.forename: Sebastian
authors.initials: S
authors.lastname: Leschka
authors.forename: Hans
authors.initials: H
authors.lastname: Scheffel
authors.forename: André
authors.initials: A
authors.lastname: Plass
authors.forename: Thomas
authors.initials: T
authors.lastname: Schertler
authors.forename: Pedro Trigo
authors.initials: PT
authors.lastname: Trindade
authors.forename: Michele
authors.initials: M
authors.lastname: Genoni
authors.forename: Philippe
authors.initials: P
authors.lastname: Cattin
authors.forename: Borut
authors.initials: B
authors.lastname: Marincek
authors.forename: Thomas
authors.initials: T
authors.lastname: Frauenfelder
mesh_terms: D000368:Aged; D009202:Cardiomyopathies / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000000981:diagnostic imaging*; D009929:Organ Size; D012015:Reference Standards; D014057:Tomography, X-Ray Computed / Q000379:methods