Implications of Three-Phase Bone Scintigraphy for the Diagnosis of Bisphosphonate-Related Osteonecrosis of the Jaw

Purpose: Bisphosphonate (BP)-related osteonecrosis of the jaw (BRONJ) is a well-known serious complication of BP treatment. This study was undertaken to evaluate the diagnostic usefulness of three-phase bone scintigraphy in patients with BRONJ. Methods: Forty-one patients (48 lesions) with clinically proven BRONJ (2 males, 39 females, age 74. 3 ± 6. 7 years) underwent Tc-99 m HDP bone scintigraphy. Visual interpretation and semiquantitative analysis of uptakes using lesion-to-contralateral uptake ratios during the blood pool phase (BUR) and during the osseous phase (OUR) were performed, and relations were sought between these and various clinical parameters. Results: Three-phase bone scintigraphy showed increased perfusion and blood pooling in 21 (63. 6 %) and 27 (81. 8 %) of 33 lesions, respectively. The osseous phase was positive for 45 (93. 8 %) of the 48 lesions. Of the four inflammatory clinical parameters of BRONJ [pus discharge, pain, swelling, and erythrocyte sedimentation rate (ESR)], patients with three or more parameters had more positive findings in vascular and blood pool phase images (p = 0. 033, p = 0. 027). By semiquantitative analysis, patients with a positive ESR had statistically higher BUR and OUR (both p < 0. 001). Higher stage BRONJ lesions had higher OUR than lower stage lesions (p = 0. 003). In addition, bone scintigraphy revealed three clinically covert BRONJ lesions without bone exposure, and four patients were up-staged based on bone scintigraphy. Conclusions: Bone scintigraphy provides a relatively sensitive means of detecting BRONJ, so it was helpful for accurate BRONJ staging. Furthermore, increased uptakes in vascular and blood pool phases of three-phase bone scintigraphy were related to the inflammatory activity of BRONJ.