Fig. 1

Preoperative magnetic resonance images. A&B, the original three-dimensional time-of-flight magnetic resonance angiography shows abnormal vessel compression in the cisternal segment of the right trigeminal nerve (yellow arrows). A persistent primitive trigeminal artery may originate from the right internal carotid artery (red arrows), which may enter Meckel’s cavity and be closely associated with the trigeminal nerve. C, three-dimensional fast imaging employing steady-state acquisition images show abnormal vessel compression in the cisternal segment of the right trigeminal nerve (yellow oval). D, preoperative maximum intensity projection reconstructed magnetic resonance angiography. A persistent primitive trigeminal artery (yellow arrow) originates from the precavernous portion of the right internal carotid artery