Eur J Nucl Med Mol Imaging 2002 Oct;29(10):1328-33
Persistent non-specific FDG uptake on PET imaging following hip arthroplasty.
Zhuang H, Chacko TK, Hickeson M, Stevenson K, Feng Q, Ponzo F, Garino JP, Alavi
A.
Hip arthroplasty is a common surgical procedure, but the diagnosis of infection
associated with hip arthroplasty remains challenging. Fluorine-18
fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) has been shown
to be a promising imaging modality in settings where infection is suspected.
However, inflammatory reaction to surgery can result in increased FDG uptake at
various anatomic locations, which may erroneously be interpreted as sites of
infection. The purpose of this study was to assess the patterns and time course
of FDG accumulation following total hip replacement over an extended period of
time. Firstly, in a prospective study nine patients with total hip replacement
were investigated to determine the patterns of FDG uptake over time. Three FDG-PET
scans were performed in each patient at about 3, 6 and 12 months post
arthroplasty. Secondly, in a retrospective analysis, the medical and surgical
history and FDG-PET imaging results of 710 patients who had undergone whole-body
scans for the evaluation of possible malignant disorders were reviewed. The
history of arthroplasty and FDG-PET findings in the hip region were reviewed for
this study. Patients with symptomatic arthroplasties or related complaints
during FDG-PET scanning were excluded from the analysis. During the entire study
period, all nine patients enrolled in the prospective study were demonstrated to
have increased FDG uptake around the femoral head or neck portion of the
prosthesis that extended to the soft tissues surrounding the femur. Among the
patients reviewed in the retrospective study, 18 patients with a history of 21
hip arthroplasties who were asymptomatic at the time of FDG-PET scan met the
criteria for inclusion. The time interval between the hip arthroplasty and the
FDG-PET study ranged from 3 months to 288 months (mean+/-SD: 80.4+/-86.2
months). In 81% (17 of 21) of these prostheses, increased FDG uptake could be
noted around the femoral head or neck portion of the prosthesis. The average
time interval between arthroplasty and FDG-PET scan in these patients was 71.3
months. In only four prostheses (19%, 4 of 21) was no abnormally increased FDG
uptake seen around the prostheses or adjacent sites. The average time interval
in these patients was 114.8 months. It is concluded that following hip
arthroplasty, non-specifically increased FDG uptake around the head or neck of
the prosthesis persists for many years, even in patients without any
complications. Therefore, to minimize the number of false-positive results for
infection with PET studies obtained to evaluate a painful hip prosthesis,
caution should be exercised when interpreting FDG uptake around the head or neck
portion of the prosthesis.
