Four cases of nocardial brain abscess.

Background: Nocardial brain abscesses are a rare central nervous system infection with high morbidity and mortality. Infection is acquired through inhalation or direct innoculation and then spreads hematogenously. They are usually associated with immunocompromised patients but may appear in otherwise healthy individuals.

Olfactory schwannoma.

Olfactory schwannomas are very rare. For this reason they have never been diagnosed preoperatively. We report a case and describe the CT and MR imaging findings.