Table I.

Visual analysis standards for different imaging methods.

Disease	Three-phase bone scan¹⁵	SPECT/CT¹⁷	⁶⁸Ga-citrate PET/CT^12,18
Periprosthetic joint infection	Positive perfusion and/or blood pool and positive delayed phase.	Hip joint: diffuse tracer uptake in the acetabulum and/or femoral prosthesis. Knee joint: diffuse tracer uptake in the tibial or femoral component.	Diffuse tracer uptake in the bone-prosthesis interface and/or abnormal tracer uptake in the periprosthetic soft-tissue. (Mild tracer uptake limited to soft-tissues and/or synovium adjacent to the neck of the hip prosthesis or synovium of knee joint prosthesis was not considered sufficient to classify as infection.)
Aseptic loosening	Negative perfusion and blood pool but positive delayed phase.	Hip joint: focal tracer uptake at the acetabulum and/or trochanter region and/or femoral prosthetic tip. Knee joint: focal tracer uptake at the tibial tray and keel and/or posterior region of femoral condyles.	No abnormal tracer uptake or just small focal tracer uptake in the stress point of the prosthesis, and without abnormal uptake of periprosthetic soft-tissue.

PET, positron emission tomography; SPECT, single-photon emission CT.