The clinical effectiveness of fused image of single-photon emission CT and facial CT for the evaluation of degenerative change of mandibular condylar head

BACKGROUND: The primary objective of this study was to assess the clinical effectiveness of fused images obtained from single-photon emission computed tomography (SPECT) and facial computed tomography (CT) for evaluating degenerative changes in the mandibular condylar head. This assessment was accomplished by comparing the Technetium-99 m methylene diphosphonate ((99m)Tc-MDP) uptake ratio with the results of clinical and radiographic findings. METHODS: The study included 17 patients (3 males and 14 females) with suspected osteoarthritis of the mandibular condyle, totaling 34 temporomandibular joints (TMJs). Based on clinical and radiographic examinations, the TMJs were categorized into four groups: normal (group N), internal derangement (group ID), osteoarthritis (group OA), and osteoarthritis sequelae (group OA(seq)). For each patient, bone SPECT and facial CT scans were registered and reconstructed to create fused SPECT/CT images. The (99m)Tc-MDP uptake levels in the TMJs were statistically compared among the four groups. RESULTS: The (99m)Tc-MDP uptake ratio showed a gradual increase in the order of the following: group N, group OA(seq), group ID, and group OA. There was a significant difference observed among groups (p = 0.003), mainly driven by the disparity between group OA and both group N (p < 0.001) and group OA(seq) (p = 0.048). CONCLUSION: Fused SPECT/CT image can be an effective tool for evaluating degenerative changes in the mandibular condylar head. The technique demonstrated the ability to differentiate between normal TMJs and those with internal derangement, osteoarthritis, or osteoarthritis sequelae. This approach holds promise as a valuable method in clinical assessments of TMJ degeneration. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s40902-023-00399-1.