Figure 2.

64-year old female with breast cancer and right posterolateral knee pain underwent ¹⁸F-NaF PET/CT for staging. A. MIP images show increased tracer activity in both acromioclavicular joints, the facet joints of L5/S1, the right knee as well as in the bones of both feet. B, C. Axial CT images demonstrate bilateral osseous density posterolateral to the femoral condyle. D-F. Fused ¹⁸F-NaF PET/CT show increased tracer uptake in the right patellofemoral joint and articulation of right gastrocnemius muscle with fabella. The tracer uptake within the left fabella is relatively normal. The scan findings are suggestive of right painful fabella syndrome and patellofemoral joint arthritis.