Prevalence and significance of extravascular incidental findings on computed tomographic angiography and magnetic resonance angiography

Computed tomographic angiography (CTA) and magnetic resonance angiography (MRA) are routinely used to evaluate patients with vascular disease. They have the ability to detect unexpected non-vascular pathology. The purpose of this study was to determine the prevalence and significance of extravascular incidental findings in patients undergoing CTA or MRA. A retrospective review of 737 patients who underwent CTA and 184 patients who underwent MRA during a five-year period was performed. Incidental findings were classified as low, moderate or high significance findings. For patients with high significance extravascular findings, assessment of the rates of appropriate follow-up was conducted. Among the CTA patients, 539 (73.1%) had incidental findings. Low, moderate and high significance findings were discovered in 514 (69.7%), 95 (12.9%) and 41 (5.6%) patients, respectively. Twenty (48.8%) patients with high significance findings received appropriate follow-up investigations. Among the MRA patients, 95 (51.6%) had extravascular findings. Low, moderate and high significance findings were present in 80 (43.5%), 27 (14.7%), and 3 (1.6%) patients, respectively. Two (66.7%) patients with high significance findings were properly followed up. In conclusion, incidental findings on CTA and MRA are very common. A small percentage of these findings could be serious and were not all adequately followed-up in our study population. Referring physicians should be aware of the potential for serious incidental findings and manage them appropriately.