Computed tomography has been utilized to guide a needle into central nervous system lesions as small as one centimeter in diameter. Direct puncture has drained many abscesses effectively, provided material for immediate Gram stain and subsequent culture, and permitted irrigation with appropriate antibiotics. Multilocular cerebral lesions and loculated extracerebral fluid collections have been aspirated and treated with this technique. Aspiration of known cystic tumors has reduced their mass and obviated some palliative decompressions. Unresectable gliomas and metastases have been biopsied prior to chemotherapy or radiotherapy. Hemorrhage and other rare complications of biopsy may be detected and immediately treated.