Clinical Presentation
A 36-year-old man with a history of intravenous drug abuse presents with right hip and flank pain radiating down his right leg.
Technique
• A 7.5 mCi dose of 67Ga-citrate is injected intravenously 3 days before scan.
• Whole-body imaging in anterior and posterior projections
Dual-detector gamma camera
Medium-energy collimators
Energy peak at 93-, 185-, and 300-keV photopeaks
Image Interpretation
Intense tracer uptake is noted in the region of the right sacroiliac joint (Fig. 107.1). Note the “cold” center on the posterior view; this suggests an advanced process with central devitalization (necrosis). Faint tracer uptake is apparent in the soft tissues of the right buttock.
Differential Diagnosis
• Osteomyelitis
• Sacroiliitis
• Soft tissue inflammation/infection
• Acute trauma
• Malignancy
Diagnosis and Clinical Follow-Up
Findings consistent with unilateral sacroiliitis (with osteomyelitis) and adjacent cellulitis. Correlative MRI demonstrates local sacroiliac bone destruction and edema of adjacent gluteus muscles.