Medscape Medical News

Multislice Spiral CT Best to Diagnose Coronary Artery Disease
This Article is in Courtesy
Circulation
Laurie Barclay, MD

Oct. 2, 2002 - A new scanning method described in a rapid access publication of Circulation, published online in advance of print on Sept. 30, may outperform currently available noninvasive methods for detected coronary artery disease (CAD). Multislice spiral computed tomography (MSCT) has a positive predictive value (PPV) of 80% and a negative predictive value (NPV) of 97%, although no head-to-head comparisons with other modalities have yet been done.

"MSCT, combined with effective heart-rate control, seems to provide an accurate noninvasive alternative to conventional angiography," lead author Koen Nieman, MD, from Erasmus Medical Center in Rotterdam, the Netherlands, says in a news release. "Because MSCT coronary angiography is safer, requires no hospital admission and involves less patient discomfort, it will become a very suitable alternative in an increasing number of patients with chest pain and suspected coronary heart disease. Earlier detection will improve the treatment of these blockages and may prevent future problems."

During MSCT, intravenous contrast injection coupled with rotation of the scanner around the body allows reconstruction of multiple cross-sectional images synchronized to cardiac rhythm using an electrocardiogram (ECG). Although inconsistent image interpretability and long scan time plagued earlier generation, four-slice scanners, the latest generation MSCT can visualize up to 16 images at once, with increased speed and accuracy. Administration of beta-blockers facilitates better images by slowing heart rate.

Two independent experts reviewed MSCT and compared the scans to subsequent conventional angiography in 59 patients with suspected CAD. Age range was 46 to 70 years, 53 patients were male, and 34 received beta-blockers.

Using angiography as the gold standard, diagnosis of no disease, single disease, or multivessel disease was accurate in 78% of patients. No patients with significant obstructions were incorrectly excluded. Of 231 evaluated branches, 86 had significant obstruction. Without exclusion of branches, the sensitivity of MSCT to identify at least half of obstructed branches was 95%. Specificity was 86%; PPV, 80%; and NPV, 97%.

"Although no direct comparisons to MRI and EBCT [electron beam computed tomography] have been conducted, they seem to be outperformed by MSCT with respect to identifying blockages in the coronary arteries," Nieman says. Circulation. Sept. 30, 2002.