Persistent primitive olfactory artery: MR angiographic diagnosis

Abstract

Persistent primitive olfactory artery (PPOA) is a relatively rare variation of the proximal anterior cerebral artery (ACA) that generally follows an extreme antero-inferior course and takes a hairpin turn. To our knowledge, incidence of PPOA has not been reported, so we researched cases in our institution records to determine incidence and investigated characteristic features of the condition on MR angiography. To isolate cases with PPOA, we retrospectively reviewed cranial magnetic resonance (MR) angiographic images of a total of 3,626 patients in our institution and collected similar images from cases with PPOA from our two affliated hospitals. We found 14 cases with PPOA (six men and eight women); 5 patients in our institution, representing an incidence of 0.14%, and 9 cases from our group hospitals. The location was on the right in six cases, left in seven, and bilateral in one. An aneurysm was found at the hairpin turn in one patient, and in another patient, the PPOA connected with the accessory middle cerebral artery (MCA) and not the distal ACA. In our institution, incidence of PPOA on MR angiography was 0.14%. We found no laterality in frequency and rare bilaterality, aneurysm at the point of the hairpin turn, and accessory MCA arising from the PPOA.