Transient photopenia of the femoral head following arthrography

In cases of suspected sepsis of the hip, a negative arthrocentesis may precede bone scintigraphy. Routine instillation of contrast material and air for localization and characterization of the hip joint was observed to produce a transient photopenic femoral head on bone scintigraphy. The photopenia, related to venous tamponade created by the temporarily increased intra-articular pressure of the arthrogram, occurs when the isotopic study is performed within a half hour of the arthrocentesis. The cases of four children suspected of having septic arthritis and/or osteomyelitis and ranging in age from 2 to 19 years are presented to illustrate the temporal relationship of reversible femoral head photopenia with sequential arthrocentesis and bone scintigraphy.