64-Channel cardiac computed tomography: intraobserver and interobserver variability (part 1): coronary angiography.
OBJECTIVE
To assess intraobserver and interobserver variation in computed tomography coronary angiography (CTA) in 3 patient cohorts at very low, low-to-intermediate, and intermediate-to-high likelihood of coronary artery disease (CAD).


METHODS
One hundred thirty-three patients underwent 64-channel CTA. Coronary arteries were analyzed by 2 experienced blinded observers and reported as having 0%, 1% to 29%, 30% to 49%, 50% to 69%, 70% to 99%, or 100% stenosis. Intraobserver and interobserver agreement was calculated at cohort level and combined.


RESULTS
Overall intraobserver and interobserver agreement was good (kappa = 0.74 and kappa = 0.78, respectively). Segmental agreement for stenoses 50% or greater and 70% or greater was greater than 96%. Disagreements were more likely in the presence of noneccentric calcification for both intraobserver (odds ratio = 0.45 and 0.22) and interobserver (odds ratio = 0.40 and 0.10) measurements.


CONCLUSIONS
Interobserver and intraobserver variability for the detection of coronary stenoses on CTA is good and justifies routine clinical use. The presence of noneccentric calcium and mixed plaque morphology are important causes of disagreement.
Nicol
Edward D
ED
Department of Cardiology, Royal Brompton Hospital and Harefield NHS Trust, London, United Kingdom. cyprusdoc@doctors.org.uk
Stirrup
James
J
Roughton
Michael
M
Padley
Simon P G
SP
Rubens
Michael B
MB
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D003287:Contrast Media; D017023:Coronary Angiography / Q000706:statistics & numerical data*; D023921:Coronary Stenosis / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007472:Iohexol / Q000031:analogs & derivatives; D016013:Likelihood Functions; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed / Q000706:statistics & numerical data*
D003287:Contrast Media; D007472:Iohexol; C038192:iopromide