While CT has consistently been proven better than digital subtraction angiography for detecting pulmonary emboli, dose considerations remain. With multidetector CT scanners, however, those concerns may no longer be relevant, according to Dutch researchers.

The investigative team compared effective doses in patients with suspected pulmonary emboli: 27 underwent MDCT angiography, 12 DSA. The effective doses for CTA were found to be moderate and even slightly lower than pulmonary DSA. The average effective doses obtained for CTA and DSA were 4.2 mSv and 7.1 mSv, respectively.

"Physicians should perform MDCT first and do DSA only when the MDCT is inconclusive," said lead author Dr. Jan W. Kuiper, a vascular and interventional radiologist at Erasmus University Medical Center.

The researchers published their results in the July issue of European Radiology.

Scan protocol at Erasmus ensures that technologists make small adjustments, such as checking patient size and ability to breath-hold. This fine-tuning results in variations in effective dose.

"These adjustments more or less individualize scan protocols, resulting in better images, reduction in motion artifacts, and dose differences," Kuiper said.

Besides reduction in dose, MDCT has other advantages. It is easier to perform than DSA, less invasive, quicker, and more cost-effective. Most patients assessed for PE usually suffer from other nonpulmonary pathology, and radiologists can get additional diagnostic information with less radiation exposure with MDCT, he said.