Diagnosis of brain abscesses with indium-111-labeled leukocytes.

Sixteen patients with intracerebral mass lesions where computed tomography (CT) was not fully conclusive with respect to the differential diagnosis between brain tumor and abscess were examined with leukocyte brain scintigraphy (LBS). Autologous leukocytes were labeled with indium-111 oxinate and were reinjected intravenously; registration with a gamma camera was performed after 24 and 48 hours. In 10 of 11 patients with the final diagnosis of a brain tumor, no accumulation of radiolabeled leukocytes could be detected in the brain. In 4 of 5 patients with the final diagnosis of brain abscess, scintigraphy showed a pronounced increase of focal activity corresponding to the lesion demonstrated with CT. The reasons for the one false-positive and the one false-negative result are discussed, and it is concluded that LBS (a) can be used to detect intracranial infection and (b) may be a useful diagnostic tool for distinguishing between brain abscess and brain tumor.