Rapid sequence CT imaging provides information about the vascular anatomy (CT angiography), locates major vessels encased by tumor, and eliminates the possibility of avascular lesions in the differential diagnosis of a head and neck tumor. Furthermore the use of density-time curves allows arterial and venous time. The patterns of density-time curves are characteristic for various lesions. For glomus complex tumors, regardless of the size and location, dynamic CT easily differentiates them from most of the simulating lesions. Angiography therefore is occasionally necessary for verification. Dynamic CT has a risk of complications the same as that of any intravenous injection of contrast material. Cerebral angiography via the femoral approach has been reported to have a risk of major complications of 0.28% and of minor complications of 6.25%.