FDG-PET and 3-phase bone scintigraphy to differentiate diffuse sclerosing osteomyelitis from other refractory chronic osteomyelitis of jaws

Objectives Diffuse sclerosing osteomyelitis (DSO) of the mandible is characterized by recurrent pain, swelling and trismus, mimicing other refractory osteomyelitis. Differentiation of DSO is very difficult by conventional imaging modalities. Inadequate diagnosis may often lead to intractable and prolonged conditions. The aim of this prospective study was to appraise the value of FDG-PET/CT and 3-phase bone scintigraphy in differentiation of DSO from other osteomyelitis of jaws.

Methods A total of 53 patients (Age: 35-90; M/F: 28/25) with osteomyelitis of jaws were enrolled in this study; Imaging characteristics of 10 DSO were compared with those of 13 bisphosphonate-related osteonecrosis of jaws (BRONJ), 14 ORN, and 16 odontogenic infection. Each patient underwent FDG-PET and 3-phase bone scintigraphy. Each image of 3-phase bone scan (perfusion, pool, static) was analyzed using 4 point grading system (G0-G3).

Results The mean SUVmax of DSO, BRONJ, ORN, and odontogenic was 1.99±0.56, 4.34±0.92, 3.34±1.95, and 2.33±1.20, respectively. DSO (PET and perfusion: 1.99±0.56 and 0.2±0.42) and odontogenic (2.33±1.20 and 0.25±0.44) showed significantly lower accumulation in PET and perfusion images than BRONJ (4.34±0.92 and 1.6±0.87). Static images in DSO (2.8±0.42) and BRONJ (2.8±0.38) showed significantly higher uptake than odontogenic (1.8±0.87), reflecting higher remodeling activities. DSO with nonbacterial inflammation demonstrated relatively low and focal FDG accumulation, in striking contrast with characteristically increased uptake in pool images. In all patients, accurate diagnoses and appropriate treatment strategies were made.

Conclusions FDG-PET combined with 3-phase bone scintigraphy is clinically useful for the differentiation of DSO from other osteomyelitis of Jaws, because these combinations facilitate differentiation of inflammation and infection from bone remodeling, which is sometimes difficult to be characterized by other images.