18F-FDG PET Imaging of the Inferior Colliculus in Asymmetric Hearing Loss

Our purpose was to use PET to evaluate the glucose metabolism of the inferior colliculus (IC) and primary auditory cortex (PAC) in patients with asymmetric hearing loss (AHL). Methods: Normalized regional F-18- FDG uptake of the IC and PAC (reference: cerebellum) was assessed in 13 subjects with AHL using a fully digital clinical PET/CT system. Results: Regional metabolism of both the IC and the PAC was significantly reduced contralateral to the most hearing-impaired ear compared with the ipsilateral side. Duration of deafness correlated positively with metabolism of the contralateral PAC but not with metabolism of the ipsilateral PAC or either of the ICs. Conclusion: Fully digital, high-resolution clinical PET scanners allow for investigating small brain stem nuclei. AHL has a significant impact on the regional glucose metabolism of the auditory pathway. Mitigation of this effect by a longer duration of deafness might indicate reorganization at the cortical level.