Extended combined 99mTc-white blood cell and bone imaging improves the diagnostic accuracy in the detection of hip replacement infections

Abstract

Although the diagnosis of hip prosthesis infection is clinically important, X-ray studies, blood chemistry and synovial fluid aspiration may be unreliable for this purpose. The aim of this study was to evaluate whether extending the time for technetium-99m labelled leucocyte imaging to 24 h post injection improves the accuracy of diagnosis of hip replacement infections. We studied 64 symptomatic patients with hip prostheses. The presence of infections was verified by intraoperative bacterial cultures, and infection was excluded either by negative operative findings or by follow-up for at least 1 year. Leucocyte imaging was done with 99mTc-hexamethylpropylene amine oxime (HMPAO)-labelled leucocytes at 2-4 h (routine images) and at 24 h (late images) after the injection of the leucocytes. In addition, bone imaging was carried out with 99mTc-hydroxydiphosphonate (HDP) at the arterial, soft tissue and metabolic phases. A standardised method was used to compare leucocyte images with bone metabolic images. In this material, there were six confirmed infections. All the bone imaging methods had a sensitivity of 100% in detecting prosthesis infections whereas the specificity varied from only 2% to 82%. Routine leucocyte imaging was less sensitive (50% vs 83%) and less specific (90% vs 100%) than late leucocyte imaging. All tests had a high negative predictive value for excluding infection (95%-100%). However, both bone (10%-38%) and routine leucocyte imaging (33%) showed a poor positive predictive value (PPV), whereas late leucocyte imaging had a PPV of 100% and a diagnostic accuracy of 98%. We conclude that late leucocyte imaging improves the specificity of diagnosis of infected hip prostheses. This type of imaging procedure should be combined with three-phase bone scintigraphy in studies of patients with painful joint replacement.

Leukocyte and bacteria imaging in prosthetic joint infection

“…Ga-citrate, the old gold-standard 67 Gallium-citrate ( 67 Ga) has been used for localising infections for over three decades (Lavender et al, 1971). The exact reason why 67 Ga accumulates in infections is still not clarified; however, several factors are governing the accumulation.…”

“…Therefore, we will not go into details about the methods and interpretation of this imaging technique. Recently, citrate was labelled with the PET radionuclide 68 Ga, which may, due to the better characteristics of a PET tracer, have potential in the future (Nanni et al, 2010;Kumar et al, 2012). 99m Tc-labelled diphosphonates (bone scintigraphy) Methods and pitfalls Three-phase bone scintigraphy is the most widely used screening nuclear-imaging procedure for diagnosing prosthetic joint infections.…”

Patient and Personnel Radiation Exposure in Sentinel Lymph Node Practice

“…In-111 işaretli lökositler, abdominal bölgenin değerlendirilmesi istendiğinde veya kronik enfeksiyonlardaki gibi geç görüntülemeye ihtiyaç duyulduğunda kullanılabilir (31,33,34,35). Özellikle ortopedik protez enfeksiyonları başta olmak üzere diğer endikasyonlarda Tc-99m HMPAO lökositler tercih edilmektedir (16). İşaretli lökositlerin de bazı kısıtlılıkları vardır.…”

“…Kronik enfeksiyonlarda nötrofil yoğunluğu daha azdır. İşaretli lökosit sintigrafisinde geç 24. saat görüntüsü şarttır, çünkü biyo-film, radyofarmasötiklerin ve işaretli hücrelerin enfekte protez alanına geçişini azaltır, lökosit akümülasyonu uzun sürer (16). Bu nedenle, lökosit görüntülemeye göre daha efektif, dokuya penetrasyonu ve infiltre nötrofillere bağlanması daha kolay olan radyoaktif işaretli antigranülosit monoklonal antikorlar daha endikedir (17).…”

Current Possibilities for Detection of Loosening of Total Hip Replacements and How Intelligent Implants Could Improve Diagnostic Accuracy

“…Examination of an infected THR can be performed by using scintigraphy, which is often combined with white blood cell imaging (Larikka et al, 2001). Scintigraphy uses radioisotopes as body radiation source by producing a two-dimensional picture using a gamma-camera for the detection of the radiation (Katz et al, 1986;Zilkens et al 1988) (Fig.…”