title: Controversies in quantification of mitral valve regurgitation: role of cardiac magnetic resonance imaging.
abstract: OBJECTIVE
  Mitral regurgitation remains a common problem, and when severe, is associated with significant morbidity and mortality. At present, echocardiography remains the primary modality for assessing both mechanism and severity of mitral regurgitation. However, recent studies demonstrate that the echocardiographic assessment of mitral regurgitation severity may be subject to variability as a result of semiquantitative parameters, dependence upon loading conditions and significant interobserver variability.
  
  
  RESULTS
  Cardiac magnetic resonance (CMR) imaging is the gold standard in the assessment of cardiac function and structure, and offers an alternative method to estimate mitral regurgitation severity. Herein, we discuss the pitfalls of echocardiography in the assessment of mitral regurgitation and describe recent data demonstrating improved accuracy of CMR in the assessment of mitral regurgitation severity. Further, CMR derived regurgitant volume of ≤55 ml is associated with freedom from surgical intervention, in contrast to traditional volumetric measures, which fail to predict the need for surgical intervention.
  
  
  CONCLUSIONS
  The CMR assessment of mitral regurgitation severity is easily performed and appears to be more accurate and predictive of the need for surgery than traditional echocardiography. These promising findings require further confirmation in larger outcome trials.
authors.affiliation: Keenan Research Centre for Biomedical Science, Division of Cardiology, St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Kim A
authors.initials: KA
authors.lastname: Connelly
authors.forename: Edwin C
authors.initials: EC
authors.lastname: Ho
authors.forename: Howard
authors.initials: H
authors.lastname: Leong-Poi
mesh_terms: D004452:Echocardiography / Q000379:methods*; D006321:Heart / Q000000981:diagnostic imaging*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008943:Mitral Valve; D008944:Mitral Valve Insufficiency / Q000000981:diagnostic imaging*; D012720:Severity of Illness Index