Harmonized quantitative bone SPECT/CT parameters for risk assessment of medication-related osteonecrosis of the jaw: multicenter study

Background: The clinical utility of harmonization of quantitative values obtained with bone single-photon computed tomography-computed tomography (SPECT/CT) for medication-related osteonecrosis of the jaw (MRONJ) classification was investigated in a Japanese multicentric study. Patients (n = 221, 255 lesions) with a clinical diagnosis of MRONJ who underwent quantitative bone SPECT/CT examinations at five hospitals were enrolled. Harmonized standard uptake values (hSUVs), including maximum (hSUVmax), peak (hSUVpeak), and mean (hSUVmean), and also metabolic bone volume (hMBV) for total volume above the threshold and total bone uptake (hTBU), calculated as hMBV×hSUVmean, were determined. One-way repeated measures analysis of variance and subsequent post hoc analysis were used for comparing harmonized quantitative values between clinical stages. Results: The hSUVmean values for Stage 1 (n = 71), 2 (n = 115), and 3 (n = 69) were 4.05 ± 2.25, 4.53 ± 2.65, and 5.56 ± 3.10, respectively, with those for hMBV 15.47 ± 9.77, 18.79 ± 11.83, and 18.71 ± 13.68, respectively, and for hTBU 64.03 ± 54.42, 81.46 ± 60.77, and 97.88 ± 72.07, respectively. hSUVmean and hTBU showed significant differences between clinical stages (p = 0.00089 and p = 0.00052, respectively). Post hoc analysis also indicated that the Stage 3 hSUVmean value was significantly higher than the Stage 1 or 2 value (p = 0.0037 and p = 0.028, respectively), while Stage 3 hTBU was significantly higher as compared with stage 1 and 2 (p = 0.0021 and p = 0.0049, respectively), with Stage 2 significantly higher than Stage 1 (p = 0.046). Conclusions: Harmonized SUVmean and TBU derived from quantitative bone SPECT/CT results from multicentric institutions were found to be objective and reliable indicators, and useful for MRONJ patient disease activity evaluation and stagings.