Figure 7. Biopsy proven discitis osteomyelitis treated with antibiotics.

A 55-year-old man with clinically suspected lumbar discitis osteomyelitis was scanned with [¹¹C]-TMP PET/CT at the initiation of empiric antibiotic therapy and after 6 more weeks of targeted antibiotic therapy. (A) Time line of patient disease sequelae and imaging. (B) Axial PET/CT images show a clear site of asymmetric [¹¹C]-TMP uptake in the left L4–L5 facet at the start of therapy and lack of uptake after 6 weeks of i.v. treatment. Facet biopsy of the left L4–L5 facet grew methicillin-sensitive S. aureus. Note: the patient received different doses of [¹¹C]-TMP, 129 MBq at the first time point and 672 MBq at the second time point; thus, the image quality was noisier at the first time point. PET images are scaled at 0–5 SUV_max. (C) The temporal morphologic sequelae of discitis osteomyelitis are demonstrated by sagittal CT images before, during, and after treatment. (D) In contrast to the PET/CT images, the gadolinium-enhanced MRI images of the patient at 10 weeks after therapy continue to demonstrate marrow replacement and contrast enhancement, findings that are nonspecific for active infection versus continued inflammation.