Persistent trigeminal artery variant detected by conventional angiography and magnetic resonance angiography-incidence and clinical significance-

Abstract

Objective: Persistent trigeminal artery variant (PTAV) is an anastomosis between the internal carotid artery (ICA) and the cerebellar artery without any interposing basilar artery segment. We discuss its probable embryological origin and emphasize clinical implications.

Methods: Retrospectively 1250 conventional cerebral angiograms and 2947 cranial magnetic resonance angiographies (MRAs) were evaluated for the patients with PTAV.

Results: Five patients (four men and one woman, 23 to 76 years of age, median age 65 years) had a PTAV. Three patients who underwent MRA had a PTAV (3/2947=0.1%). Four of the patients who underwent cerebral angiography had a PTAV (4/1250=0.32%). Two of 143 patients who underwent both conventional angiography and cranial MRA showed PTAV. The PTAV was an incidental finding in all five patients. The PTAV originated from the cavernous segment of the left ICA in four patients and from the cavernous segment of the right ICA in one patient. The terminal branch of the PTAV was the anterior inferior cerebellar artery (AICA) and superior cerebellar artery (SCA) in two patients and the AICA only in the other three patients.

Conclusion: Neurosurgeons should be aware of possible presence of PTAV. Manipulation of this vessel during a surgical approach to the parasellar region and percutaneous gasserian ganglion procedure may result in hemorrhage or ischemia.

Keywords: Clinical implication; Incidence; Persistent trigeminal artery variant.

Fig. 1

Patient 1. Left internal carotid angiograms, anteroposterior view (A) and lateral view (B), showing the persistent trigeminal artery variant (arrow) anastomosing the cavernous portion of the internal carotid artery to the anterior inferior cerebellar artery. Axial three-dimensional time-of-flight magnetic resonance source image (C) showing an abnormal vessel originating from the cavernous portion of the left internal carotid artery. Three-dimensional time-of-flight magnetic resonance angiography (D) showing a persistent trigeminal artery variant originating from the cavernous portion of the left internal carotid artery.

Fig. 2

Patient 3. Left internal carotid angiograms, anteroposterior view (A) and lateral view (B), showing the persistent trigeminal artery variant (arrow) anastomosing the cavernous portion of the internal carotid artery to the superior cerebellar artery and anterior inferior cerebellar artery (arrow head).