Dual time point 2-[18F]fluoro-2'-deoxyglucose positron emission tomography in chronic bacterial osteomyelitis.

Objective: Quantitative dual time point imaging with [F]fluorodeoxyglucose positron emission tomography (F-FDG PET) has recently been found to be more accurate than single time point scanning in the discrimination between benign lesions and malignancy in various conditions. In our study we investigated glucose metabolism in chronic bacterial osteomyelitis (COM) by using F-FDG PET and a dual time protocol.

Methods: Seventeen non-diabetic patients with histopathologically proven COM and four non-diabetic patients with malignant bone disease were prospectively investigated with dual time F-FDG PET. All lesions were detected by their increased F-FDG uptake 30 and 90 min after injection of 370 MBq of F-FDG. The maximum and mean lesional standardized uptake values (SUV(max) and SUV(mean) after 30 and 90 min were determined.

Results: The median SUV(max) and SUV(mean) values of all osteomyelitic lesions at 30 min were 1.85 (range, 0.45-3.45) and 1.1 (range, 0.21-1.99), respectively. The median SUV(max) and SUV(mean) values of all malignant lesions at 30 min were 3.19 (range, 2.31-4.7) and 2.82 (range, 2.4-3.71), respectively. At 90 min the median SUV(max) and SUV(mean) of all osteomyelitic lesions were 1.78 (range, 0.4-2.93) and 1.1 (range, 0.18-1.72), respectively. At the same time point the median SUV(max) and SUV(mean) of all malignant lesions were 4.1 (range, 3.52-5.32) and 3.34 (range, 2.81-4.12), respectively. In osteomyelitis the SUV(max) and SUV(mean) between 30 and 90 min post-injection remained stable or decreased in 16/17 patients. In these patients a median decrease of 6% for SUV(max) (range, 1-31%) and a median decrease of 8.5% for SUV(mean) (range, 0-24%) was observed. Changes of SUV(max) and SUV(mean) between 30 and 90 min were highly significant (P<0.05). In one patient SUV(max) and SUV(mean) increased over the time. The histology of this patient revealed multiple foreign body granulomas in addition to a mononuclear infiltrate. In malignant lesions the SUV(max) and SUV(mean) between 30 and 90 min post-injection increased.

Conclusion: Our preliminary results indicate that dynamic dual time point F-FDG PET provides a characteristic pattern in chronic osteomyelitis similar to inflammatory processes in other locations. This pattern may be of value in the differentiation between COM and malignant bone lesions.