title: Time-effectiveness, observer-dependence, and accuracy of measurements of left ventricular ejection fraction using 4-channel MDCT.
abstract: OBJECTIVE
  To evaluate the time-effectiveness, inter-observer variance, and accuracy of left ventricular ejection fraction (EF) measurements using retrospectively ECG-gated four-channel multi-detector row CT (MDCT) angiography in comparison with biplane cine-ventriculography.
  
  
  METHODS
  Twenty consecutive patients underwent retrospectively ECG-gated MDCT angiography and conventional coronary angiography with biplane ventriculography. Raw MDCT data were reconstructed at 0 % - 90 % of the cardiac cycle in increments of 10 %. Ten geometrically identical multiplanar reformations parallel to the short axis of the heart were reconstructed in each patient. Three blinded readers segmented the left ventricle in the end-systolic and end-diastolic phase using standardized window settings in order to determine the EF. The EF was measured with biplane cine-ventriculography by two blinded readers and was compared with MDCT. The time needed for post-processing was recorded and the inter-observer agreement for both imaging techniques was assessed.
  
  
  RESULTS
  Mean post-processing time was 63 +/- 3 min per patient for MDCT and 5.5 +/- 1.2 min for ventriculography. MDCT and ventriculography showed a good correlation (r = 0.83, p < 0.0001) for measurement of the EF. Mean errors of EF measurements for the three MDCT readers compared with the mean of the ventriculography were - 6.3 +/- 6.6 %, - 4.7 +/- 7.1 % and - 4.6 +/- 5.7 %, respectively. The mean differences between the three readers assessing MDCT were - 1.6 +/- 3.2 % (reader 1 versus 2, r = 0.96), - 1.6 +/- 5.6 % (1 versus 3, r = 0.95) and - 0.011 +/- 2.9 % (2 versus 3, r = 0.97, p < 0.0001). The mean differences between the two readers assessing ventriculography was 0.32 +/- 5.1 % (r = 0.88, p < 0.0001).
  
  
  CONCLUSIONS
  MDCT correlates well with biplane cine-ventriculography but has the tendency to underestimate the left ventricular EF. Measurements using MDCT have a high inter-observer agreement, however, the time needed for additional MDCT data post-processing is still unacceptably long.
authors.affiliation: Department of Radiology, Kantonsspital, Chur, Switzerland. thomas_boehm@gmx.net
authors.forename: T
authors.initials: T
authors.lastname: Boehm
authors.forename: H
authors.initials: H
authors.lastname: Alkadhi
authors.forename: M
authors.initials: M
authors.lastname: Roffi
authors.forename: J K
authors.initials: JK
authors.lastname: Willmann
authors.forename: L M
authors.initials: LM
authors.lastname: Desbiolles
authors.forename: B
authors.initials: B
authors.lastname: Marincek
authors.forename: S
authors.initials: S
authors.lastname: Wildermuth
mesh_terms: D000368:Aged; D000465:Algorithms; D000792:Angiography / Q000379:methods*; D017023:Coronary Angiography; D004562:Electrocardiography; D005260:Female; D005544:Forecasting; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D012189:Retrospective Studies; D013318:Stroke Volume; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000379:methods*; D016277:Ventricular Function, Left