Computed tomography of the cerebellopontine cistern in normal and acoustic tumor patients

Air computed tomography of the cerebellopontine cistern was performed in 15 consecutive patients. The series comprised 7 patients with a normal cistern and 8 patients with tumor, including one with bilateral tumors. Two tumors were of small size (less than 10 mm i diameter), 3 were medium sized (10-20 mm in diameter), and 4 were large (greater than 20 mm in diameter). In the normal group, the jugular foramen nerve bundle (the 9th, 10th and 11th nerves), the trigeminal nerve, or the brain stem margin were clearly defined by air. In the tumor group, the possible extension of the tumor to these structures could be defined. Differentiation between a compression or attachment of the trigeminal nerve to the tumor was not always possible. The importance of using reconstruction views is stressed.