Hybrid imaging systems in the diagnosis of osteomyelitis and prosthetic joint infection.

Early diagnosis of osteomyelitis and prosthetic bone infection is essential for successful therapy and prevention of complications. Nuclear medicine offers a variety of modalities for this aim, including both single photon emission tomography (SPET) and positron emission tomography (PET) radiopharmaceuticals. The main limitation of these functional images is the fact that they are lacking the structural delineation of the pathologic processes; this important drawback can sometimes render interpretation difficult and diminish the diagnostic capability. The recent availability of hybrid SPET/computed tomography (CT) and PET/CT devices that acquire both functional and anatomical data can solve these problems. In fact, the combination of SPET or PET with CT provides exact anatomical registration with bone and joint lesions and improves the accuracy of the nuclear medicine images. This article reviews the currently available literature and addresses the use of hybrid systems in the diagnosis of osteomyelitis and prosthetic bone infection. The first reports indicate that hybrid imaging is very useful in these indications, because it is able to provide further information of clinical value in several cases. The advantage of accurately localizing the areas of increased radiotracer uptake allows a precise differentiation between soft tissue and bone infection, that is crucial for the choice of therapy and patients' management. However, data are still very limited and further studies are needed to verify if hybrid imaging may really become clinically relevant in the near future for early diagnosis of osteomyelitis and prosthetic bone infection.