Cardiac CT Scan is Limited for Detecting Blockages
Too many nonevaluable segments, but may be useful for excluding heart disease in select patients
TUESDAY, July 25 (HealthDay News) -- Detection of coronary atherosclerosis with 16-row multi-detector computed tomography (MDCT) can result in a higher number of nonevaluable segments and false-positive results than traditional angiography, though it may be useful in ruling out heart disease in some patients with inconclusive stress test results, according to a report in the July 26 issue of the Journal of the American Medical Association.
Mario J. Garcia, M.D., of the Cleveland Clinic Foundation in Ohio, and colleagues compared the results of 187 patients who underwent contrast-enhanced MDCT scans, as well as conventional angiographies performed within two weeks.
Of 1,629 non-stented coronary artery segments with diameters more than 2 millimeters, 71 percent were able to be evaluated by MDCT scan. When nonevaluable segments were classified as positive, the sensitivity for detecting more than 50 percent stenosis was 89 percent, the specificity was 65 percent, the positive predictive value was 13 percent and the negative predictive value was 99 percent.
"Routine implementation in clinical practice is not justified," the authors write. "Nevertheless, given its high sensitivity and negative predictive value, 16-row MDCT may be useful in excluding coronary disease in selected patients in whom a false-positive or inconclusive stress test result is suspected."
The study was funded by Philips Medical Systems, which provides recommendations on computed tomography X-ray dosing.