Nuclear medicine imaging of bone infections

Abstract

The inflammation and infection of bone include a wide range of processes that can result in a reduction of function or in the complete inability of patients. Apart from the inflammation, infection is sustained by pyogenic microorganisms and results mostly in massive destruction of bones and joints. The treatment of osteomyelitis requires long and expensive medical therapies and, sometimes, surgical resection for debridement of necrotic bone or to consolidate or substitute the compromised bones and joints. Radiographs and bone cultures are the mainstays for the diagnosis but often are useless in the diagnosis of activity or relapse of infection in the lengthy management of these patients. Imaging with radiopharmaceuticals, computed tomography and magnetic resonance are also used to study secondary and chronic infections and their diffusion to soft or deep tissues. The diagnosis is quite easy in acute osteomyelitis of long bones when the structure of bone is still intact. But most cases of osteomyelitis are subacute or chronic at the onset or become chronic during their evolution because of the frequent resistance to antibiotics. In chronic osteomyelitis the structure of bones is altered by fractures, surgical interventions and as a result of bone reabsorption produced by the infection. Metallic implants and prostheses produce artefacts both in computed tomography and magnetic resonance images, and radionuclide studies should be essential in these cases. Vertebral osteomyelitis is a specific entity that can be correctly diagnosed by computed tomography or magnetic resonance imaging at the onset of symptoms but only with radionuclide imaging is it possible to assess the activity of the disease after surgical stabilization or medical therapy. The lack of comparative studies showing the accuracy of each radiopharmaceutical for the study of bone infection does not allow the best nuclear medicine techniques to be chosen in an evidence-based manner. To this end we performed a meta-analysis of peer reviewed articles published between 1984 and 2004 describing the use of nuclear medicine imaging for the study of the most frequent causes of bone infections, including prosthetic joint, peripheric post-traumatic bone infections, vertebral and sternal infections. Guidelines for the choice of the optimal radiopharmaceuticals to be used in each clinical condition and for different aims is provided.

Leukocyte and bacteria imaging in prosthetic joint infection

“…In particular, haematopoietically active marrow usually develops around joint prostheses, producing an alteration of the normal distribution of the bone marrow. Furthermore, in peripheral bones, especially after orthopaedic surgery, there are often displacements of bone marrow with "hot spots" that must be distinguished from focal infection (Prandini et al, 2006).…”

“…It is most sensitive when the prosthesis has been implanted at least 2 to 5 years earlier (for hip and knee, respectively). Bone scintigraphy is largely available with low cost (Prandini et al, 2006). It consists of a dynamic imaging sequence (early phase), called the flow or perfusion phase (first phase), followed immediately by static images of the region of interest, the blood-pool or soft-tissue phase (second phase).…”

Patient and Personnel Radiation Exposure in Sentinel Lymph Node Practice

“…Özellikle diz ve kalça protez enfeksiyonlarında ameliyat üzerinden 2 yıldan fazla zaman geçtiyse hassasiyet artmaktadır (25). Uygulama kan akımı veya perfüzyonu gösteren dinamik fazı (ilk faz) takiben ilgi alanına ait kan havuzu veya yumuşak doku fazını gösteren statik görüntüleri (ikinci faz) ve enjeksiyondan 2-4 saat sonra alınan planar statik geç görüntülerden (üçüncü faz) oluşur.…”

“…Kemik sintigrafisini yorumlamada, radyofarmasötik tutulum özelliklerindeki değişkenlikler nedeni ile asemptomatik hastalarda ve özellikle diz protezlerinde sorunlar mevcuttur. Buna yönelik bazı araştırmacılar tarafından kantitatif analiz ve yorumlamada yardımcı olabilecek sınıflandırmalar denenmiş, ancak bu sorun çözülememiştir (9,10,25,26). Cerrahi sonrasındaki yıllarda aktivite tutulumları değişik oranlarda devam edebilir.…”

Imaging Vascular Endothelial Growth Factor (VEGF) Receptors in Turpentine-Induced Sterile Thigh Abscesses with Radiolabeled Single-Chain VEGF

“…More recent investigations have shown that macrophages and angiogenic endothelial cells express high levels of monocyte chemoattractant peptide 1, vascular endothelial growth factor (VEGF), and VEGF receptors; these findings suggested that these cell types work with each other to generate and maintain chronic inflammation in a variety of disorders, including bacterial, fungal, and viral infections, rheumatologic and autoimmune disorders, atherosclerosis, organ transplant rejection, and cancer (6)(7)(8). A noninvasive method for assessing the presence, location(s), extent, and intensity of increased VEGF receptor expression would be of clinical value, particularly in chronic joint and soft-tissue infections, which are notoriously difficult to detect with standard markers (such as gallium, 18 F-FDG [with PET], and radiolabeled white blood cells) (9)(10)(11). Serial imaging of VEGF receptor expression could also be quite helpful in guiding biologic modifier therapy for common chronic noninfectious inflammatory disorders (such as rheumatoid arthritis, inflammatory bowel disease, and multiple sclerosis), for which annual drug costs alone can be as high as $10,000-$50,000 (12)(13)(14).…”