Mixed bag for CT angiography

Candace Stuart, Editor

Findings on CT angiography (CTA) dominated two research journals in recent weeks, or so it would seem. Both Radiology and the Journal of the American College of Cardiology published several studies in the past month that scrutinized the use of CTA in the clinical setting.

Published in Radiology, Guang Ming Lu, MD, of the Nanjing University in Nanjing, China, and colleagues compared digital subtraction CTA and 3D rotational digital subtraction angiography (DSA) to determine which approach best evaluated intracranial aneurysms. While DSA is considered the standard approach for detecting intracranial aneurysms, advancements in multidetector CT techniques have made digital subtraction CTA an attractive option because of its less invasive and less time consuming nature.

They found digital subtraction CTA had both high sensitivity and specificity, although it was challenging to detect smaller aneurysms and those in uncommon locations.

In another study in Radiology, researchers examined newer, faster CTA protocols for depicting acute ischemic stroke to determine their ability to accurately estimate infarct size. In this study, they assigned patients to either the new or old CTA protocol, with all patients also getting diffusion-weighted MR imaging exams. The new, faster CTA protocol overestimated infarct size and could have inappropriately excluded up to 60 percent of patients from treatment.

The effectiveness of CTA to exclude or confirm the presence of obstructive coronary artery disease (CAD) may depend on the pretest probability for CAD and coronary calcium scoring, according to a study in the Journal of the American College of Cardiology. The study was designed to evaluate the diagnostic accuracy of CTA in patients with calcium scores of 600 or greater.

They found diagnostic accuracy to detect obstructive CAD was reduced in this patient group compared with patients whose scores were less than 600. The finding prompted an editorial writer to recommend CTA not be extended to patients with substantial calcification.

And lastly, risk-adjusted analyses of the SPARC study showed that changes in aspirin and lipid-lowering agent use was greater in patients without a documented history of CAD and an intermediate to high likelihood of CAD who underwent 64-slice coronary CTA compared with stress SPECT or PET. The CTA group was more likely to undergo cardiac catheterization after normal/nonobstructive and mildly abnormal study findings as well.

Stay tuned. I am sure we will hear more about the benefits and pitfalls of these technologies throughout the year.

Candace Stuart
Cardiovascular Business, editor
cstuart@CardiovascularBusiness.com