[The persistent trigeminal artery as evidenced by multislice spiral computed tomographic angiography]

To determine the incidence of the persistent trigeminal artery (PTA) and to reveal its relationship to cerebral aneurysms, as well as the concomitant anatomic features of cerebral arteries according to the data of multislice spiral computed tomographic angiography (CTA). MATERIAL AND METHODS. A total of 1041 patients underwent brachiocephalic artery CTA according to different clinical indications. PTA and cerebral arterial aneurysms were found on the computed tomographic angiograms and the anatomic features of the structure of the circle of Willis were assessed.

PTA was identified in 6 (0.58%) of the 1041 patients. Cerebral aneurysm was present in only one patient with PTA and concurrent with hypoplasia of the contralateral A1 segment of the anterior cerebral artery. Hypoplasia of the basilar artery (BA) and both vertebral arteries (VA) was observed in 3 (60%) cases, with the diameter of PTA at its confluence with BA exceeding 3 mm. When the diameter of BA was normal, that of PTA was less than 2 mm. All PTAs were wider at their base, by decreasing in diameters distally.

CTA showed that the incidence of PTA was 0.58% and its lateral type according to the Salas classification and Saltzman's type 1 were more common (5/6). In 4 cases, PTA was concurrent with VA and BA hypoplasia, with its degree being inversely related to the distal diameter of PTA. There was no convincing evidence for a relationship of PTA to cerebral aneurysms.