title: Accuracy of mitral valve area measurements using transthoracic rapid freehand 3-dimensional scanning: comparison with noninvasive and invasive methods.
abstract: OBJECTIVE
  The feasibility and accuracy of direct transthoracic 3-dimensional (3D) mitral valve area (MVA) measurements obtained using freehand scanning was investigated in patients with mitral stenosis.
  
  
  METHODS
  A total of 30 patients (26 women, 4 men; aged 55 +/- 13 years) underwent a 2-dimensional (2D) and Doppler study 1 hour before percutaneous balloon mitral valvuloplasty. Transthoracic freehand data were acquired using a magnetic receiver attached to a broadband transducer, gated to electrocardiography and respiration. Volumetric MVA measurements from the left ventricle and left atrium were obtained and compared with MVA measurements derived from 2D planimetry, pressure half-time, and proximal isovelocity surface area. Invasive Gorlin MVA measurements were the gold standard for comparison.
  
  
  RESULTS
  In all, 29 patients (97%) had 3D data allowing MVA measurements. Direct 3D measurements from the left ventricle had the least bias (0.06 +/- 0.19 cm(2)) and tightest limits of agreement (-0.44 to 0.32) compared with left atrium measurements (0.17 +/- 0.25 cm(2) and -0.67 to 0.33, respectively). The proximal isovelocity surface area method (bias: 0.09 +/- 0.34 cm(2)) was the most accurate of all 2D methods followed by pressure half-time (0.17 +/- 0.36 cm(2)) and planimetry (0.21 +/- 0.29 cm(2)).
  
  
  CONCLUSIONS
  Direct 3D MVA measurements from the left ventricle using transthoracic freehand scanning are more accurate than traditional 2D methods.
authors.affiliation: Department of Medicine, University of Chicago Medical Center, IL 60637, USA. lsugeng@medicine.bsd.uchicago.edu
authors.forename: Lissa
authors.initials: L
authors.lastname: Sugeng
authors.forename: Lynn
authors.initials: L
authors.lastname: Weinert
authors.forename: Georgeanne
authors.initials: G
authors.lastname: Lammertin
authors.forename: Patrick
authors.initials: P
authors.lastname: Thomas
authors.forename: Kirk T
authors.initials: KT
authors.lastname: Spencer
authors.forename: Jeanne M
authors.initials: JM
authors.lastname: Decara
authors.forename: Victor
authors.initials: V
authors.lastname: Mor-Avi
authors.forename: Dezheng
authors.initials: D
authors.lastname: Huo
authors.forename: Ted
authors.initials: T
authors.lastname: Feldman
authors.forename: Roberto M
authors.initials: RM
authors.lastname: Lang
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015150:Echocardiography, Doppler / Q000379:methods*; D019560:Echocardiography, Three-Dimensional / Q000379:methods*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000000981:diagnostic imaging*; D008946:Mitral Valve Stenosis / Q000000981:diagnostic imaging*; D015588:Observer Variation