Renal artery aneurysms: diagnosis and surveillance with 3D contrast-enhanced magnetic resonance angiography

The use of contrast-enhanced magnetic resonance angiography (CE-MRA) in screening for suspected renovascular disease may result in increased detection of renal artery aneurysms. We report the CE-MRA findings at diagnosis and follow-up in nine hypertensive patients with unsuspected renal artery aneurysms. A search of renal CE-MRAs of suspected renal artery stenosis at two tertiary referral institutions over 5 1/2 years was performed. All patients underwent CE-MRA using a fast spoiled gradient echo technique (TR/TE/flip 5.1–6 ms/1.6 ms/40°), scan matrix 512×196–224, 1 excitation, FOV 400–450 mm×266–360 mm, 32–50 mm×1.5–2 mm interpolated slices. Gadolinium-enhanced 3D images were obtained during breath holding. Images were evaluated and post-processed on a workstation by a single operator. Nine patients with renal artery aneurysms out of a total of 912 cases were found, all involving the main artery or divisions proximal to the renal hilum. Renal arteries distal to the hilum were not consistently visualized. The aneurysm was bilobed in one patient, multilocular in another and unilocular in all others. Severe stenosis of the renal artery proximal to the aneurysm was present in two. Four patients underwent follow-up showing no change in aneurysm size. CE-MRA reliably identifies aneurysms involving the main renal arteries and proximal branches. Once diagnosed, CE-MRA offers a safe, non-invasive modality for surveillance of aneurysm if active intervention is not planned.