Skull Base Overview

Imaging Approaches and Indications

CT is primary imaging tool for evaluating bony details of the skull base (SB). Multislice CT scanners allow thin slices (≤ 1 mm) & provide multiplanar reformatted images. These function as a mainstay for evaluating bony changes associated with SB diseases and providing evidence for calcific/bony matrices of these lesions.

MR is an essential partner to bone CT in evaluating SB lesions as it provides the best understanding of lesion soft tissue extent. T1 precontrast images show lesion margins against the contrast of skull base marrow fat. T1 also reveals high-signal subacute blood and intralesion high-velocity flow voids to best advantage. Enhanced, fat-saturated T1 sequences define enhancement characteristics of the lesion in question. GRE may show blooming if hemorrhage or venous sinus thrombosis is present. DWI hyperintensity in a focal SB lesion suggests the diagnosis of epidermoid. MRA and MRV are important sequences to acquire if internal carotid and vertebral artery or venous sinus involvement is suspected.