Alternative available to contrast dyes for some medical scans

The use of ionizing radiation with iodide contrast dye in CT scans is being questioned because of a possible link to thyroid damage.

"They're lifesaving and tremendous advances, but there's always another side of the coin," says Dr. Fady Charbel, head of the department of neurosurgery at the University of Illinois at Chicago.

Patients who had signs of thyroid disease were between two and three times as likely to have had a scan using iodide as a comparison group of people without thyroid problems, according to a study in the Archives of Internal Medicine.

But experts advise patients not to decide against having a scan because of the data.

"It seems that in patients who have received iodine contrast media, there has been an association with thyroid disturbance. ... This is a strong association," Charbel says. "The causality, is it something that will change the practice in medicine? We don't necessarily know. But it's one more piece of data physicians will think of when they order these studies, and they wonder what is another (study) we can order."

One of the alternative tests would be an MRI. Charbel is the inventor of NOVA (Noninvasive Optimal Vessel Analysis), a noninvasive MRI study that is noncontrast-based.

NOVA is a flow analysis system that works with magnetic resonance imaging to produce a 3-D model of the vasculature and quantify vessel blood flow. The procedure received FDA approval in 2001. It is used to diagnose conditions such as stroke and aneurysms, but has other potential applications.

VasSol, a privately held company founded in 2001 and of which Charbel is president and chief scientific officer, also has developed NOVA applications to provide blood-flow information about vessels in the kidneys and lower extremities.

"Certainly if you're looking at a CAT scan, an angiogram, which has a need ... to give a lot of contrast dye, NOVA comes out way ahead," Charbel says.

Reuters contributed to this story.

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