SPECT Imaging of Brain and Tinnitus-Neurotologic/Neurologic Implications.

Single Photon Emission Computed Tomography (SPECT) of brain with technetium-99m hexamethyl propyleneamine oxine (Tc-HMPAO) is an imaging technique which has been introduced for the identification of abnormalities of regional cerebral blood flow (rCBF) in patients with a central type of subjective idiopathic tinnitus, which was characterized as severe and disabling. These patients demonstrate a negative clinical history, physical examination does not evidence central nervous system disease, and CT/MRI studies of brain were negative. Two typical cases are presented which demonstrate significant regional abnormalities in cerebral perfusion bilateral of temporal, frontal, parietal and hippocampal amygdala regions when compared with normative Tc-HMPAO SPECT of brain data. Neurotologic and neurologic implications are suggested which include cerebrovascular disease, neurodegenerative disorder and dementia, and neuropsychiatric mood disorder. SPECT results of brain demonstrate for the first time the in vivo significance of the organicity of brain for a central type of tinnitus.