Speaking at the 34th Annual scientific meeting of the Society of Interventional Radiology, held in San Diego, USA, 7-12 March 2009, Dr Seth Toomay, University of Texas Southwestern, found that computed tomography angiography and magnetic resonance angiography have similar sensitivities and specificities.
In a presentation entitled “Computed tomography angiography or magnetic resonance angiography for occlusive peripheral artery disease: which test is better?”, Toomay began by clarifying that lower limb peripheral arterial disease is characterised by atheromatous narrowing or occlusion of one or more of the arteries of the leg. Symptoms include intermittent claudication, ischaemic rest pain, ulceration and gangrene and patients showed an ankle-brachial pressure index < 0.90, he said.
Disclosing that his department used computed tomography, Toomay said that the advantages of the system were easy availability, rapid acquisition and lower cost. He also drew attention to the fact that the disadvantages in using computed tomography for peripheral arterial disease included radiation, the need for a nephrotoxic contrast agent, and decreased sensitivity for patients showing extensive vascular calcifications, 3D reconstruction time.
On the other hand, he said, magnetic resonance had the advantages of not requiring a nephrotoxic contrast agent, it did not have the same sensitivity to calcium and significantly, there was no radiation from the procedure. But the disadvantages included patients developing nephrogenic systemic fibrosis associated with exposure to gadolinium, frequently used as a contrast substance for magentic resonance imaging, and increased cost. Contraindications included patients who had pacemakers, claustrophobia, and being aware that metal could cause MRI artifacts.
Referencing Ouwendijk et al and their 2005 publication in journal Radiology, Toomey said that when it came to computed tomography vs. magentic resonance, both provide equivalent diagnostic confidence.
“Interventions planned with computed tomography angiography or magentic resonance angiography are both successful,” said Toomey.
He pointed out that, with both procedures, six-month outcomes are equivalent, and recommended to colleagues to “use the test that works best for you.”