Can sequential 18F-FDG PET/CT replace WBC imaging in the diabetic foot?

Area of Science:

• Nuclear Medicine
• Diagnostic Imaging
• Diabetic Foot Complications

Background:

• White blood cell (WBC) scintigraphy is the established gold standard for diagnosing osteomyelitis in diabetic foot patients.
• Emerging evidence suggests (18)F-FDG PET/CT may offer similar diagnostic accuracy, but lacks defined interpretation criteria.

Purpose of the Study:

• To evaluate sequential (18)F-FDG PET/CT for diagnosing diabetic foot osteomyelitis.
• To establish objective interpretation criteria for (18)F-FDG PET/CT and compare its accuracy to WBC scintigraphy.

Main Methods:

• Thirteen patients with suspected osteomyelitis underwent both (99m)Tc-exametazime WBC scintigraphy and sequential (18)F-FDG PET/CT.
• Biopsy or tissue culture was used for definitive diagnosis.
• Various qualitative and quantitative interpretation criteria were tested for both imaging modalities.

Main Results:

• WBC scintigraphy achieved 92% accuracy using a target-to-background ratio > 2.0 at 20 hours.
• (18)F-FDG PET/CT demonstrated lower diagnostic accuracy (54%) with defined criteria.
• Combining visual PET and CT assessment improved differentiation but remained suboptimal.

Conclusions:

• Sequential (18)F-FDG PET/CT exhibits low diagnostic accuracy for diabetic foot osteomyelitis.
• (18)F-FDG PET/CT cannot currently replace WBC scintigraphy for diagnosing this condition.
• Further research is needed to improve PET/CT interpretation criteria.