Cranial CT artifacts and gantry angulation.

Computed tomographic investigation of the brain is frequently accomplished by scanning parallel to the canthomeatal line. In these scans, evaluation of the brain stem and neighboring structures is often compromised by streak artifacts from bone-induced beam hardening. These artifacts may be reduced by introducing a change in gantry angulation. Results from a phantom study as well as from a clinical trial offer evidence that may be helpful in assessing different scanning planes. An inclination of 5 degrees below Reid baseline is suggested to minimize the interpetrous artifact. Variations in slice thickness and exposure parameters do not appear to affect significantly this typical posterior fossa artifact.