Screening CT angiography identifies additional abnormalities in fibromuscular dysplasia

Last Updated: 2016-09-28

By Will Boggs MD

NEW YORK (Reuters Health) - CT angiography (CTA) identifies additional vascular abnormalities in nearly half of patients with fibromuscular dysplasia (FMD), according to a new study.

"This study involved patients who had already been diagnosed with FMD and referred to our center for further analysis, and we found our imaging screening beneficial," said Dr. Michael A. Bolen from Cleveland Clinic, Ohio.

"However, imaging is also key in the initial diagnosis of patients with suspected FMD based upon clinical presentation. In this clinical scenario, CTA can be useful as a large vascular territory can be evaluated with good spatial resolution in one examination," he told Reuters Health by email.

FMD can result in stenosis, dissection, or aneurysm of nearly all arterial distributions, with renal, carotid, and vertebral arteries most commonly affected. Its angiographic appearance resembles a string of beads, with the beaded areas appearing larger in caliber than the unaffected sections of the artery.

Dr. Bolen's team reviewed the first 113 FMD patients (112 women) who were imaged with a specialized CTA protocol in order to characterize the pathologic findings and to assess the effects of screening CTA on clinical management.

Most patients (96%) had multifocal FMD, 42% had a history of dissection, and 16% had a known aneurysm, the researchers report in JACC: Cardiovascular Imaging, online September 16.

CTA abnormalities included beading, aneurysm, dissection, and stenosis/occlusion in aortic, renal, mesenteric, iliac, and coronary distributions. Renal arteries were affected most often (67% of patients), followed by lower extremity/iliac arteries (32% of patients). Only 3% of patients had aortic abnormalities.

Findings not previously noted included beading in 49% of patients, focal stenosis in 1%, new aneurysms in 19%, and new dissections in 3%.

The use of reformatted images affected the final assessment in 56% of cases evaluated by reader 1 and in 36% of cases evaluated by reader 2. The readers showed 84% to 96% agreement in diagnosis.

The researchers note that digital subtraction angiography (DSA) could improve the detection of subtle vascular abnormalities, but it is invasive and costly. Another imaging option is magnetic resonance angiography (MRA), but it is more time intensive than CTA, and its spatial resolution is slightly inferior to that of CTA.

"Collaborative efforts between referring clinicians seeing patients with suspected FMD and radiologists protocoling/reporting imaging findings will likely provide the best patient outcome," Dr. Bolen said. "Clinicians will identify potential patients with this relatively uncommon diagnosis, and relay this suspicion to radiologists who can appropriately protocol and analyze the imaging results."

"We found benefit in performing specialized imaging reformats in this patient group," he said. "Additionally, appropriate scanning technique can keep radiation burden low in this predominantly female patient group."

An accompanying editorial notes that, "The report by Bolen and colleagues is important because it clearly shows that if a patient has FMD in one location, imaging other vascular beds often leads to the identification of FMD, aneurysms, and/or dissections."

"Further investigation is needed in order to determine the best imaging technique and frequency of imaging in patients with FMD," write Dr. Jeffrey W. Olin and Dr. Daniella Kadian-Dodov from Icahn School of Medicine at Mount Sinai, New York.

"Additionally, following these patients over time will clarify the natural history of the disease and outcomes so that optimal surveillance imaging and management can be instituted," they add.

SOURCE: http://bit.ly/2cVczrL and http://bit.ly/2d3N6hP

J Am Coll Cardiol Img 2016.