A1 segment hypoplasia accompanied by AcomA aneurysms assessed with magnetic resonance angiography.

PURPOSE

This study is to evaluate the use of three-dimensional time-of-flight magnetic resonance angiography (3D-TOF MRA) at 3.0 T for the detection and classification of A1 segment hypoplasia based on a large case series and investigates the potential links with AcomA aneurysm occurrence.

METHODS

Between January 2009 and June 2012, 8,013 patients underwent MRA examination at 3.0 T in our hospital. MRA was performed using 3D-TOF with volume rendering technique. The presence and location of A1 segment hypoplasia and AcomA aneurysm was reviewed.

RESULTS

Among the 8,013 patients examined, 138 patients were identified with AcomA aneurysms. 425 patients were defined with A1 segment hypoplasia, among whom 303 right-sided A1 hypoplasia and 122 left-sided A1 hypoplasia. 60 of these 425 patients were confirmed with AcomA aneurysms, among them were 49 right-sided A1 hypoplasia. The prevalence of AcomA aneurysm with A1 segment hypoplasia was 14.1 %, which was much higher compared with that (1.0 %) of AcomA aneurysm without A1 segment hypoplasia (P < 0.001).

CONCLUSIONS

The incidence of right-sided A1 segment hypoplasia either accompanied with AcomA aneurysm or not was much greater than that of left-sided. Intracranial AcomA aneurysm development appeared to be associated with A1 segment hypoplasia.