Radionuclide imaging of the painful joint replacement: past, present and future

Abstract

Differentiating aseptic loosening from infection as the cause of prosthetic joint failure is difficult because both entities are similar, clinically and histopathologically. Aseptic loosening frequently results from an immune reaction to the prosthesis. There is inflammation with an influx of histiocytes, giant cells, lymphocytes, and plasma cells. Proinflammatory cytokines and proteolytic enzymes are secreted, causing osteolysis and loosening. These same events occur in infection except that neutrophils, rarely present in aseptic loosening, are invariably present in infection. Clinical signs and symptoms, laboratory tests, x-rays and joint aspiration are insensitive, nonspecific or both. Artifacts produced by the metallic hardware hamper cross-sectional imaging modalities. Radionuclide imaging is not affected by the presence of metallic hardware and is very useful for evaluating the painful prosthesis. Bone scintigraphy, with an accuracy of 50%-70% is a useful screening test, since a normal study effectively excludes a prosthetic complication. Adding gallium-67, a nonspecific inflammation-imaging agent, improves the accuracy of bone scintigraphy to 70%-80%. The accuracy of combined leukocyte/marrow imaging, 90%, is the highest among available radionuclide studies. Its success is due to the fact that leukocyte imaging is most sensitive for detecting neutrophil mediated inflammations. Inflammatory conditions that are neutrophil-poor, even though large numbers of other leukocytes may be present, (such as the aseptically loosened joint prosthesis) go undetected. The success of leukocyte/marrow imaging is tempered by the limitations of in-vitro labeling. In-vivo labeling has been investigated and a murine monoclonal antigranulocyte antibody appears promising. Some investigations have focused on F-18 FDG imaging, although specificity is a concern with this agent.<br>É difícil diferenciar o afrouxamento asséptico do infeccioso como causa da falência de uma prótese articular pois ambas as entidades são similares clinica e histopatologicamente. O afrouxamento asséptico frequentemente resulta de uma reação imune à prótese. Há inflamação com o influxo de histiócitos, células gigantes, linfócitos e plasmócitos. Citocinas pró-inflamatórias e enzimas proteolíticas são secretadas causando osteólise e afrouxamento. Estes mesmos eventos ocorrem na infecção, exceto que os neutrófilos raramente presentes no afrouxamento, estão invariavelmente presentes na infecção. Os sinais e sintomas clínicos, os testes laboratoriais, radiografias e aspirados da articulação não apresentam sensibilidade, especificidade ou ambos. Artefatos produzidos pelos aparelhos metálicos dificultam as imagens cross-seccionais. A imagem com radionuclídeos não é afetada pela presença de aparelhos metálicos e é muito útil para avaliação de próteses dolorosas. A cintigrafia óssea, com uma acurácia de 50 a 70% é um teste valioso de rastreamento, desde que um resultado normal exclui complicações da prótese. Com o gálio-67, um agente não-específico para imagens infl...

12 Chapters on Nuclear Medicine

“…But lower results for this combination has also been reported because the uptake of both tracers can be found not only in infection, but also in the postoperative patient, in heterotopic bone formation, and loosening or inflammatory reaction to cement fixators (El-Maghraby et al, 2006;as cited in Turpin & Lambert, 2001). Labelled leukocyte imaging is, at least theoretically, the ideal technique for diagnosing the infected prosthesis because in general, white cells do not accumulate at sites of increased bone mineral turnover in the absence of infection (Palestro, 1998). However, labelled-leukocytes yield false positive results due to reactive or displaced bone marrow as a result of surgery are present up to more than 24 months after implantation (El-Maghraby et al, 2006;as cited in Oswald et al, 1990).…”

Radionuclide imaging of infection: what the future holds

“…Any other pattern is negative for infection. The overall accuracy of combined leukocyte/marrow imaging is approximately 90% (Love et al, 2001;Palestro et al, 2002;Palestro et al, 2007). Labeled leukocyte imaging is not useful for detecting spinal osteomyelitis because 50% or more of these cases present as areas of decreased or absent activity.…”

Avaliação de processos inflamatórios na articulação temporomandibular empregando leucócitos autólogos marcados com tecnécio-99m em modelo animal

“…A captação de radioatividade observada na bexiga é devida à eliminação renal do complexo HMPAO marcado com 99m Tc. Parte do complexo 99m Tc-HMPAO pode deixar o interior dos leucócitos, iniciando um processo de eliminação renal, minutos após a injeção dos leucócitos radiomarcados (13,14) .…”