Prediction and assessment of response to anti-inflammatory therapy in medication-related osteonecrosis of the jaw using harmonized quantitative bone SPECT/CT: A multicenter study.

OBJECTIVE: The utility of harmonized quantitative bone single-photon emission computed tomography/computed tomography (SPECT/CT) parameters for prediction and assessment of treatment response to anti-inflammatory therapy for medication-related osteonecrosis of the jaw (MRONJ) was investigated in a multicenter study conducted in Japan. SUBJECTS AND METHODS: Thirty-eight patients (40 lesions) clinically diagnosed with MRONJ underwent bone SPECT/CT scanning before initiation of anti-inflammatory therapy and again after at least three months of treatment at five hospitals. Using the GI-BONE software package, quantitative parameters including standard uptake value (SUV) parameters (SUVmax, SUVpeak, and SUVmean), metabolic bone volume (MBV), and total bone uptake (TBU) were calculated. Changes in quantitative parameters between the first and second SPECT/CT examinations were analyzed using the Wilcoxon test in both responders (downstaged lesions) and non-responders (upstaged lesions or no stage change). Pre-treatment values were compared between responders and non-responders using Student's t-test. RESULTS: Following therapy, harmonized SUVmax, SUVpeak, SUVmean, MBV, and TBU values decreased significantly in the 23 responder lesions (P<0.0001 for all). In contrast, no significant reductions were observed in the 17 non-responder lesions (P=0.18, P=0.26, P=0.19, P=0.86, and P=0.31, respectively). Changes in harmonized SUVmax differentiated responders from non-responders with a sensitivity of 91.3% and specificity of 88.2%, using an optimal cut-off value of -17.0%. The corresponding sensitivity and specificity values for harmonized TBU change were 82.6% and 94.1%, respectively, with an optimal cut-off value of -38.0%. Pre-treatment harmonized SUVmax and SUVpeak were significantly higher in responders than in non-responders (P=0.049 and P=0.047, respectively). CONCLUSION: Harmonized quantitative bone SPECT/CT parameters, including SUV-derived parameters, MBV, and TBU, were useful for predicting and assessing anti-inflammatory therapeutic response in patients with MRONJ. Furthermore, higher pre-treatment SUVmax and SUVpeak were associated with a favorable response to anti-inflammatory therapy.