title: Assessment of mitral valve adaptation with gated cardiac computed tomography: validation with three-dimensional echocardiography and mechanistic insight to functional mitral regurgitation.
abstract: BACKGROUND
  Mitral valve (MV) enlargement is a compensatory mechanism capable of preventing functional mitral regurgitation (FMR) in dilated ventricles. Total leaflet area and its relation with closure area measured by 3-dimensional (3D) echocardiography have been related to FMR. Whether these parameters can be assessed with other imaging modalities is not known. Our objectives are to compare cardiac computed tomography (CT)-based measurements of MV leaflets with 3D echocardiography and determine the relationship of these metrics to the presence of FMR.
  
  
  RESULTS
  We used 2 cohorts of patients who had cardiac CT to measure MV total leaflet, closure, and annulus areas. In cohort 1 (26 patients), we validated these CT metrics to 3D echocardiography. In cohort 2 (66 patients), we assessed the relation of MV size with the presence of FMR in 3 populations: heart failure with FMR, heart failure without FMR, and normal controls. Cardiac CT and 3D echocardiography produced similar results for total leaflet (R(2)=0.97), closure (R(2)=0.89), and annulus areas (R(2)=0.84). MV size was the largest in heart failure without FMR compared with controls and patients with FMR (9.1 ± 1.7 versus 7.5 ± 1.0 versus 8.1 ± 0.9 cm(2)/m(2); P<0.01). Patients with FMR had reduced ratios of total leaflet to closure areas and total leaflet to annulus areas when compared with patients without FMR (P<0.01).
  
  
  CONCLUSIONS
  MV size measured by CT is comparable with 3D echocardiography. MV enlargement in cardiomyopathy suggests leaflet adaptation. Patients with FMR have inadequate adaptation as reflected by decreased ratios of leaflet area and areas determined by ventricle size (annulus and closure areas). These measurements provide additional insight into the mechanism of FMR.
authors.affiliation: Cardiac MR PET CT Program and Cardiac Ultrasound Laboratory, Division of Cardiology, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Beaudoin
authors.forename: Wai-Ee
authors.initials: WE
authors.lastname: Thai
authors.forename: Bryan
authors.initials: B
authors.lastname: Wai
authors.forename: Mark D
authors.initials: MD
authors.lastname: Handschumacher
authors.forename: Robert A
authors.initials: RA
authors.lastname: Levine
authors.forename: Quynh A
authors.initials: QA
authors.lastname: Truong
mesh_terms: D000222:Adaptation, Physiological; D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D055424:Cardiac-Gated Imaging Techniques / Q000379:methods*; D009202:Cardiomyopathies / Q000000981:diagnostic imaging / Q000503:physiopathology; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D019560:Echocardiography, Three-Dimensional; D005260:Female; D006333:Heart Failure / Q000000981:diagnostic imaging / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000000981:diagnostic imaging*; D008944:Mitral Valve Insufficiency / Q000000981:diagnostic imaging* / Q000503:physiopathology; D061330:Multidetector Computed Tomography; D011237:Predictive Value of Tests; D015203:Reproducibility of Results
keywords: 3-dimensional echocardiography; cardiac computed tomography; mitral valve insufficiency