18F-fluorodeoxyglucose-PET for patients with suspected spondylitis showing Modic change.

Abstract

Prospective cohort study. To examine the utility of 18F-fluorodeoxyglucose-positron emission tomography (FDG-PET) to diagnose pyogenic spondylitis in patients showing Modic change. Vertebral bone marrow infection may appear as Modic type 1 signal on magnetic resonance imaging, so it is difficult to distinguish between common Modic change and infection. In the current study, we aimed to examine the utility of 18F-FDG-PET to diagnose pyogenic spondylitis in patients showing Modic change. In a prospective assessment of 312 patients showing low back pain, 18 patients were suspected of having pyogenic vertebral osteomyelitis because of their symptoms, biopsy results, blood analysis, x-ray examination, magnetic resonance imaging, and FDG-PET during a 1-year follow-up. Observers ultimately diagnosed 11 patients with pyogenic spondylitis (group 1 observers). FDG-PET evaluation by 2 radiologists (group 2 observers) showed isotope accumulation in the lumbar spine in 11 patients, and no accumulation in 7 patients. The evaluation by group 1 observers, who did not see the FDG-PET findings, was compared with the evaluation by group 2 observers. No patients were evaluated differently by group 1 and group 2 observers. In conclusion, the rate of detecting spondylodiscitis infection was very high if FDG-PET was additionally used. FDG-PET is recommended to distinguish between common Modic change and spinal infection.