title: Cardiac MR assessment of aortic regurgitation: holodiastolic flow reversal in the descending aorta helps stratify severity.
abstract: OBJECTIVE
  To assess the utility of holodiastolic flow reversal (HDR) in the descending aorta on velocity-encoded cardiac magnetic resonance (MR) images in the stratification of aortic regurgitation (AR) severity.
  
  
  METHODS
  This study was approved by the institutional review board, with waiver of informed consent. A total of 80 patients (overall mean age, 49 years ± 18 [standard deviation]; 22 women and 58 men) with clinical indication for cardiac MR imaging of the aorta were analyzed retrospectively. Velocity-encoded MR imaging was used to quantify AR and assess for HDR at the level of the middescending aorta. These indexes were compared with a qualitative integrated echocardiographic evaluation of AR severity. Sensitivity and specificity for HDR in the prediction of substantial AR were determined, and logistic regression analysis (with associated odds ratios and C statistics) was performed, with HDR and regurgitant fraction as independent predictors. An additional 42 patients (overall mean age, 48 years ± 21; 12 female and 30 male) were then prospectively evaluated in similar fashion to evaluate a decision model derived from analysis of the first group.
  
  
  RESULTS
  HDR predicted severe AR (echo grade, 4) with high sensitivity (100%) and specificity (93%). HDR was highly specific (100%) but had lower sensitivity (61%) for moderate to severe AR (echo grade, 3-4). Integration of HDR and direct AR quantification into a combined stratification model based on analysis of the primary group showed good predictive results in the validation group, with a C statistic of 0.94 for moderate to severe AR and 0.93 for severe AR.
  
  
  CONCLUSIONS
  HDR in the middescending thoracic aorta observed at cardiac MR is indicative of severe AR and can be used in conjunction with quantified regurgitant values obtained from velocity-encoded MR imaging to stratify AR severity.
authors.affiliation: Imaging Institute, Cardiovascular Section, Cleveland Clinic, 9500 Euclid Ave, Room J1-4, Cleveland, OH 44195, USA. bolenm@ccf.org
authors.forename: Michael A
authors.initials: MA
authors.lastname: Bolen
authors.forename: Zoran B
authors.initials: ZB
authors.lastname: Popovic
authors.forename: Prabhakar
authors.initials: P
authors.lastname: Rajiah
authors.forename: Ruvin S
authors.initials: RS
authors.lastname: Gabriel
authors.forename: Andrew O
authors.initials: AO
authors.lastname: Zurick
authors.forename: Michael L
authors.initials: ML
authors.lastname: Lieber
authors.forename: Scott D
authors.initials: SD
authors.lastname: Flamm
mesh_terms: D001011:Aorta / Q000000981:diagnostic imaging / Q000473:pathology*; D001022:Aortic Valve Insufficiency / Q000000981:diagnostic imaging / Q000473:pathology*; D005260:Female; D006801:Humans; D018810:Magnetic Resonance Angiography; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D008875:Middle Aged; D055414:Myocardial Perfusion Imaging; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014463:Ultrasonography