Persistent primitive olfactory artery: CT angiographic diagnosis and literature review for classification and clinical significance.

Objectives: The aim of this study was to investigate the incidence of a persistent primitive olfactory artery (POA) and to review the literatures focusing on the classification and clinical significance of this variant.

Design: To identify cases with persistent POA, we reviewed the records of computed tomography (CT) angiography performed on 3,067 patients in our institution from January 1, 2011 to August 31, 2013. Literatures on the incidence and classification of a persistent POA were reviewed.

Results: Among these patients, eight were diagnosed with a persistent POA (five men, three women, aged 44-82 years), an incidence of 0.26 %. Six persistent POAs terminated as a distal anterior cerebral artery (ACA) and two as a distal middle cerebral artery. Previous studies applied similar definitions for the classification of persistent POA; however, there has been confusion on the definition of variant 2.

Conclusion: In our institution, the incidence of persistent POA seen on CT angiography was 0.26 %. An artery with its embryological course along the olfactory bulb should be classified as a persistent POA and differentiated from dural artery from ACA.