Hip Osteoarthritis Associated with Prominent Synovitis Revealed by ⁶⁸Ga-FAPI PET/CT

Area of Science:

• Nuclear Medicine
• Radiochemistry
• Orthopedics

Background:

• Aseptic loosening of acetabular prostheses is a common complication after hip replacement surgery.
• Synovial inflammation (synovitis) is increasingly recognized as a factor in osteoarthritis (OA) pathogenesis.
• Novel imaging agents are needed to visualize synovial activity in OA.

Purpose of the Study:

• To evaluate the utility of 68Ga-FAPI PET/CT in a patient with hip pain after prosthesis revision.
• To assess the role of synovial activity in the development of osteoarthritis.
• To highlight 68Ga-FAPI PET/CT as a tool for visualizing synovial inflammation.

Main Methods:

• A 56-year-old patient with a history of left acetabular prosthesis revision underwent 68Ga-FAPI PET/CT.
• Initial diagnosis of aseptic loosening was made based on imaging findings.
• Follow-up imaging was performed due to new onset of right hip pain.

Main Results:

• Initial 68Ga-FAPI PET/CT suggested aseptic loosening of the left acetabular prosthesis.
• Follow-up 68Ga-FAPI PET/CT revealed increased tracer uptake in the right hip.
• This finding led to a diagnosis of synovitis-induced osteoarthritis in the right hip.

Conclusions:

• 68Ga-FAPI PET/CT effectively visualizes synovial activity.
• Synovitis may play a significant role in the pathogenesis of osteoarthritis.
• This case demonstrates the clinical utility of 68Ga-FAPI PET/CT in diagnosing OA and understanding its underlying mechanisms.