TC-99M MIBI BRAIN SPECT OF CEREBELLOPONTINE ANGLE TUMORS

To prospectively evaluate the imaging feasibility of Tc-99m sestamibi brain SPECT of cerebellopontine angle (CPA) tumors, seven patients wit h CPA lesions seen on CT or MRI and five normal control subjects under went brain SPECT using a triple-headed camera, Five of these patients had acoustic neuromas, one had a meningioma, and the other had a vascu lar loop, Subsequently, four patients underwent surgery. In normal con trol subjects and patients with CPA lesions, there was Tc-99m sestamib i activity in the pituitary gland, choroid plexi, and extraocular musc les, The uptake in these structures, especially the choroid plexi coul d not be blocked by the oral administration of potassium perchlorate i n two normal subjects, Four of seven patients with CPA lesions larger than 1.0 cm in diameter showed tumor uptake (3 acoustic schwannomas, 1 meningioma), Two small (>1.0 cm in diameter) intracanalicular type ac oustic neuromas failed to show uptake, despite additional attenuation correction for the petrous bone, There was no abnormal uptake in the p atient with a vascular loop in the CPA, Preliminary data suggest that, with the exception of small intracanalicular neuromas, CPA tumors can be imaged using Tc-99m sestamibi brain SPECT.