Imaging System Tested For Visualizing Stents

Hank Russell

NEW YORK -- A multislice CT scanner with echocardiogram triggering designed to give surgeons real-time images of the abdominal aorta and the iliac arteries is being tested, according to Dr. Frans L. Moll in a presentation at the Veith symposium on vascular medicine sponsored by Montefiore Medical Center.

"For the first time, we're able to visualize the stent graft in the aorta after [it is] placed there and, after excluding the aneurysm sac," we can see how the stent "influences the elasticity, the natural movement, or physiology, of the aortic environment," said Dr. Moll of the University Medical Center Utrecht, the Netherlands.

Eight gated data sets, covering the heart cycle with 12.5% steps, were reconstructed. The abdominal aorta and iliac arteries were acquired in 14-33 seconds (mean time 21 seconds). Image quality was rated good or excellent in all patients. Diameter variation during the cardiac cycle of the infrarenal neck of the aneurysm was seen to almost completely disappear after stent placement, although stent movement varied from 0 mm to 3 mm per cardiac cycle.

"It's getting eight data sets per heart cycle; that's great. So you have video with the catheters in your body, you're lying on a bed going through a tunnel, and you get the images in 21 seconds," Dr. Moll said.

The device has been under development for more than a year by the University Medical Center Utrecht in conjunction with Philips Medical Systems Research.

Patients who underwent endovascular aneurysm repair received a breath-hold scan with a standard radiation dose of 17.5-21 mGy, 1.25-mm collimation, and a pitch of 0.2-0.3. Scan duration was recorded.