Fetal origin of the posterior cerebral artery:variation of multi-segments of the circle of Willis demonstrated with 64-slice spiral CT angiography

Objective To investigate the value of 64-slice spiral CT angiography (CTA) in demonstrating variations of multi-segments of the Circle of Willis (CoW) in patients accompanying fetal origin of the posterior cerebral artery (FTP). Methods The imaging of 201 FTP patients diagnosed by 64-slice CTA and 201 non- FTP patients selected as the control group were comparatively analyzed. We observed the anomalies of the CoW morphology on 64-slice CTA. Results Compared with the control group, patients with an FTP are more prone to develop variations of the A1 segment of the anterior cerebral artery (P0.01), P1 segment of the posterior cerebral artery (P0.001) and vertebral arteries (VA) (P0.001). Furthermore, small, hypoplasia or absence of ipsilateral A1 segment and P1 segment occurred more frequently in the unilateral FTP patients as compared to the controls (P0.001). And the right VA is more prone to develop variations than the left (P0.01). The variation of posterior communicating arteries (PCoA), anterior communicating artery (ACoA ) and basilar artery (BA) did not differ significantly between the two groups (P0.05). Conclusion Patients with an FTP are frequently affecting more than one segment of CoW. 64-slice spiral CTA can evaluate the anatomy and variation of cerebral vessels roundly which conduce to conduct the diagnosis and therapy of cerebral vascular diseases.