title: Transaortic flow velocity from dual-source MDCT for the diagnosis of aortic stenosis severity.
abstract: OBJECTIVE
  To describe a method for the estimation of transaortic flow from multidetector computer tomography (MDCT).
  
  
  BACKGROUND
  Cardiac MDCT may not allow instantaneous flow measurement yet the components of flow, namely, volume change over time and lumenal area are recorded.
  
  
  METHODS
  In 36 patients, the transaortic flow velocity was determined on transthoracic echocardiography and also with cardiac MDCT as follows: On MDCT an axial orientation through the aortic root was obtained so that the nadir of all three aortic leaflets could be seen simultaneously in one axial image. Aortic valve area (AVA) was determined by planimetry and left ventricular volumes by endocardial border mapping at every 5% increment of the RR intervals. Flow velocity was then calculated as the incremental ejection volume ÷ duration of the increment ÷ AVA.
  
  
  RESULTS
  The transthoracic echocardiography (TTE) peak velocity and MDCT peak velocity were highly correlated (r = 0.75, P < 0.01). Transaortic peak velocity was higher when measured by MDCT as compared to TTE, with respectively a median [IQ-range] of 4.5 [2.9-5.3] and 4.0 [3.0-4.6], P < 0.01. For the diagnosis of severe aortic stenosis greater concordance with TTE peak velocity was seen with MDCT peak velocity (sensitivity 100%, specificity 76%) than with MDCT AVA (sensitivity 74%, specificity 76%).
  
  
  CONCLUSIONS
  We show for the first time that transaortic flow velocity can be estimated by dual-source MDCT and has a better sensitivity for the detection of severe aortic stenosis than AVA planimetry when compared to the gold standard of TTE peak flow velocity.
authors.affiliation: Department of Cardiology, Erasmus MC Rotterdam, The Netherlands.
authors.forename: Carl J
authors.initials: CJ
authors.lastname: Schultz
authors.forename: Stella-Lida
authors.initials: SL
authors.lastname: Papadopoulou
authors.forename: Adriaan
authors.initials: A
authors.lastname: Moelker
authors.forename: Rutger J
authors.initials: RJ
authors.lastname: Nuis
authors.forename: Gert J R
authors.initials: GJ
authors.lastname: Ten Kate
authors.forename: Nico R
authors.initials: NR
authors.lastname: Mollet
authors.forename: Marcel L
authors.initials: ML
authors.lastname: Geleijnse
authors.forename: Pim
authors.initials: P
authors.lastname: de Feyter
authors.forename: Peter
authors.initials: P
authors.lastname: de Jaegere
authors.forename: Patrick W
authors.initials: PW
authors.lastname: Serruys
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001021:Aortic Valve / Q000000981:diagnostic imaging* / Q000503:physiopathology; D001024:Aortic Valve Stenosis / Q000000981:diagnostic imaging* / Q000503:physiopathology; D001783:Blood Flow Velocity; D005260:Female; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D009426:Netherlands; D015588:Observer Variation; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography