Three-phase bone scintigraphy for imaging osteoradionecrosis of the jaw

This study evaluates the diagnostic utility of 3-phase bone scintigraphy for diagnosing osteoradionecrosis of the jaw (ORNJ).

Thirty-two consecutive patients with a history of radiation to the head and neck region (range, 62-70 Gy; mean, 68 Gy; median, 69 Gy) due to squamous cell cancer and suspected ORNJ underwent 3-phase bone scans after injection of 520 to 750 MBq of Tc-MPD. In addition to planar scans, tomographic images (SPECT) were acquired in the second phase and SPECT/CT images during the third phase. Histopathologic findings (n = 18) and clinical follow-up (n = 14) served as reference standard for osteoradionecrosis.

The first, second, and third phases of planar images were rated positive in 18/32 patients (56.3%), 25/32 (78.1%), and 27/32 patients (84.4%), respectively. The late SPECT was positive in all patients (32/32, 100%), respectively. Histopathologic findings available in 18/32 patients (56.3%) confirmed ORNJ in all subjects. Acute inflammation was histologically proven in 18/18 specimens (100%) and additional chronic inflammation in 12/18 (66.7%). In 13/18 (72.2%) specimens, superinfection was evident histopathologically. A photopenic defect with surrounding hypermetabolism, a reported hallmark of ORJN, was found in less than 5%.

The predominant scintigraphic pattern of osteoradionecrosis includes increased bone mineralization phase in all patients. Central photopenia, reportedly a typical bone scan finding in bisphosphonate-induced osteonecrosis, was not characteristic for ORNJ. A differentiation of acute from chronic inflammatory processes was not possible.