Objective This study aims to investigate regional cerebral glucose metabolism and regional cerebral blood flow(rcBf) of tinnitus patients and to map specific foci sites of tinnitus perception in brain imaging.

Methods ¹⁸F-FDG and ¹³N-NH₃.H₂O PET/CT brain imaging were performed on 43 tinnitus patients and 40 controls.

Results were evaluated with visual analysis and roi analysis by whole brain analyses. Results PET data demonstrated the asymmetric activation of the central system of tinnitus patients compared with controls. Twenty-four patients revealed increased metabolism of the unilateral hemisphere, including 32 brain areas prior to the left superior temporal gyrus, left middle temporal gyrus, left supramarginal gyrus, right superior temporal gyrus, and right middle temporal gyrus. In addition, 75% of the 32 areas revealed increased rCBF. Ten patients showed increased metabolism in bilateral hemispheres, including 20 brain areas(10 on each side); 90% of which revealed increased rCBF. Five patients showed reduced metabolism and rCBF of the unilateral hemisphere, including the right superior temporal gyrus and right middle temporal gyrus. Cortical activation was independent from tinnitus laterality.

Conclusions Tinnitus perception may involve more brain areas than the auditory cortex, prior to increased glucose metabolism activity and rCBF. Cortical activation was independent from tinnitus laterality. Cerebral glucose metabolism was consistent with rCBF.