Multidetector Spiral CT Renal Angiography in the Diagnosis of Renal Artery Fibromuscular Dysplasia

Objective: The aim of this study was to evaluate the role and detection rate of multidetector spiral CT renal angiography (CTA) as compared with conventional angiography (CA), the commonly accepted gold standard, in the diagnosis of renal artery fibromuscular dysplasia (FMD). In addition, the role of CTA reconstructions (multiplanar reformatted images (MPR), maximum intensity projections (MIP) and shaded-surface display (SSD)) in the detection of FMD was also evaluated.

Materials And Methods: CTA results were retrospectively reviewed in 21 hypertensive patients with CA-proven FMD. Clinical indications for referral included resistant hypertension (requiring greater than three antihypertensive medications), labile hypertension, hypertension in combination with renal impairment and the presence of abdominal bruits in the context of systemic hypertension. In some cases, these clinical indications were supplemented by positive results in other tests, including plasma renin assay, captopril scintigraphy and/or Doppler ultrasound. The findings of CA in these 21 patients were compared to CTA.

Results: Mean patient age was 62.33+14.32 years (range 24-85 years). CTA identified all 42 main renal arteries (100%) and all 10 accessory renal arteries (100%) visualized on CA. In the diagnosis of FMD, CTA detected all 40 (100%) lesions detected by CA. No single CTA reconstruction technique was able to detect all lesions noted on corresponding CA, however, upon review of all CTA reconstructions (MPR, MIP and SSD) in each case, every lesion was correctly identified by CTA.

Conclusion: Our experience suggests that CTA is a non-invasive, reliable and accurate method for the diagnosis of renal artery fibromuscular dysplasia. Moreover, in our experience CTA has many advantages as a diagnostic screening tool over CA, including accessibility, speed, lower complication profile, versatility and cost-effectiveness. CTA shows great potential as a guiding tool for directing subsequent procedures such as CA+balloon angioplasty.