Evaluation of temporal and facial osteomyelitis by simultaneous In-WBC/Tc-99m-MDP bone SPECT scintigraphy and computed tomography scan.

A reliable imaging technique is needed for follow-up of patients with temporal and facial osteomyelitis. Clinical outcome in 20 patients with suspected osteomyelitis of the temporal/mastoid, calvarium, and mandible facial bones was evaluated with 30 combined In-WBC/Tc-99m MDP bone single photon emission computed tomographic (SPECT) scans and 27 computed tomographic scans. Simultaneous dual-tracer 25-minute SPECT scans were acquired 18 to 20 hours after radiotracer injection by use of a three-detector system. Diagnosis of the 20 patients (age range, 3 to 74 years) included 8 with facial osteomyelitis, 6 with malignant otitis externa, 3 with mandibular osteomyelitis, and 3 with calvarial osteomyelitis. Diagnosis was confirmed by biopsy/culture results in 18 patients and by endoscopic and clinical evaluation in 2 patients with initial negative scans. Of the 30 In-WBC/MDP scans, 15 were true-positive, 13 true-negative, 1 false-negative, and 1 equivocal. Of a total of 27 CT scans, 9 were true-positive, 5 false-negative, and 1 equivocal in patients with biopsy-proven osteomyelitis. Three computed tomographic scans were false-positive and 1 was equivocal in patients without osteomyelitis, because of concurrent postoperative bone abnormalities. Additionally, 8 computed tomographic scans were true-negative. These results suggest that dual In-WBC/Tc-99m MDP bone SPECT scintigraphy provides an accurate imaging modality for diagnosis and follow-up of temporal and facial osteomyelitis when existing clinical or postoperative bone changes make it difficult to detect active osteomyelitis by computed tomographic scan.