SPECT/CT of femeroacetabular impingement.

Femoroacetabular impingement is a recently described condition thought to be associated with early onset osteoarthritis. We describe 2 cases of femoroacetabular impingement that were initially unrecognized despite multimodality imaging, including radiographs, MRI, and scintigraphy. The scintigraphic appearance may mimic avascular necrosis. There are limited reports of femoroacetabular impingement in the nuclear medicine literature. We propose that the finding of increased uptake in the superior femoral neck associated with osteoarthritic uptake involving the superior hip joint suggests the diagnosis of either cam or mixed cam-pincer impingement.