Screening CT Angiography of the Aorta, Visceral Branch Vessels, and Pelvic Arteries in Fibromuscular Dysplasia.

OBJECTIVES: This study sought to evaluate the diagnostic yield of a dedicated computed tomography angiography (CTA) protocol of the chest, abdomen, and pelvis in patients with fibromuscular dysplasia (FMD).

BACKGROUND: FMD is an uncommon vascular disease that may result in stenosis, dissection, or aneurysm of nearly all arterial distributions, typically affecting medium-sized arteries. Findings from the United States Registry for Fibromuscular Dysplasia have suggested the potential need to perform screening imaging of the aorta and medium branch vessels.

METHODS: A total of 113 consecutive patients enrolled in our institutional FMD registry who received a tailored CTA protocol at our institution between March 2013 and June 2015 were included in this study. Arterial phase contrast-enhanced images were obtained on a dual-source scanner using high pitch and electrocardiogram trigger. Images were analyzed by 2 readers.

RESULTS: Abnormalities including beading, aneurysm, dissection, and stenosis/occlusion were noted in aortic, renal, mesenteric, and iliac distributions. The most commonly affected vessels were the renal arteries (n = 76 [67%]), followed by the lower extremity/iliac arteries (n = 37 [32%]). Aortic abnormalities were less frequently encountered (n = 3 [3%]), including 1 case with mild dilation (4.2 cm) of the ascending aorta and 2 cases of dissection involving the descending aorta, 1 with mild dilation (4.4 cm). Incremental findings beyond those known at patient intake were commonly noted, including new areas of arterial beading (n = 55 [49%]), new aneurysms (n = 21 [19%]), and new dissections (n = 3 [3%]). Reformatted images were crucial, affecting final assessment in 56% of cases evaluated by reader 1 and 36% evaluated by reader 2.

CONCLUSIONS: Screening chest, abdomen, and pelvis CTA in patients with FMD showed substantial and incremental diagnostic yield. Reformatted images should routinely be included in imaging analysis. Abnormalities in the aorta were not common, so screening of the thoracic aorta may not be indicated.