Quantitative evaluation of bone single-photon emission computed tomography using Z score analysis in patients with mandibular osteomyelitis.

Abstract

Bone scintigraphy is a functional imaging that allows early detection of bone changes, providing high sensitivity to detect osteomyelitis. The aims of this study were to develop a quantitative evaluation method for bone SPECT images of mandibular osteomyelitis, and to confirm the reliability of this method by comparing the results with the conventional subjective evaluation and other findings. The study included 139 patients with suspected mandibular osteomyelitis who were examined by bone SPECT. Tc-99m uptake in mandibular lesions was subjectively evaluated by comparing with that of cervical vertebrae and categorized into 5 groups. For quantitative evaluation of Tc-99m uptake, we developed an anatomical standardization followed by Z-score analysis applied to the diagnosis of brain neurodegenerative disease. To confirm reliability, the correlation between subjective evaluation and Z-score was evaluated. Further, the relationship between the Z-score and CT findings suggestive of osteomyelitis was also evaluated. The correlation coefficient of voxel values was significantly improved by anatomical standardization. The Z-score of osteomyelitis was significantly correlated with subjective evaluation. It was also related to some of the CT findings (bone absorption, periosteal reaction, surrounding soft tissue inflammation). We developed the quantitative evaluation method of the mandible on bone SPECT images using anatomical standardization followed by Z-score analysis, and it was considered useful for evaluating mandibular osteomyelitis quantitatively.