Wertigkeit der SPECT/CT für die nuklearmedizinische Entzündungsdiagnostik

Abstract

Even today infection remains a significant concern, and the diagnosis and localization of infectious foci is an important health issue. As an established infection-imaging modality, nuclear medicine plays a vital health-care role in the diagnosis and subsequent effective treatment of this condition. Several techniques in nuclear medicine significantly aid infection diagnosis, including triple-phase bone scanning, 18 F-FDG-PET and imaging with 111 In-oxine-, 99m Tc-HMPAO-labeled leukocytes. Each radiopharmaceutical has specific advantages and disadvantages that makes it suitable to diagnose different infectious processes (e. g., soft-tissue sepsis, inflammatory bowel disease, osteomyelitis, occult fever, fever of unknown origin, and infections commonly found in immuno-compromised patients). However, their clinical applications may be limited by the relatively low spatial resolution and the lack of anatomic landmarks of a highly specific tracer with only scarce background uptake to use as a framework for orientation. Anatomic imaging modalities such as CT provide a high-quality assessment of structural abnormalities related to infection, but these structural abnormalities may be unspecific. Furthermore, to detect infection before anatomical changes are present, functional imaging could have some advantages over anatomical imaging. Scintigraphic studies have demonstrated high sensitivity and specificity to an infectious process. Diagnosis and precise delineation of infection may be challenging in certain clinical scenarios, rendering decisions concerning further patient management difficult. The SPECT/CT-technology combines the acquisition of SPECT and CT data with the same imaging device enabling perfect overlay of anatomical and functional images. SPECT/CT imaging data has been shown to be beneficial for many clinical settings such as indeterminate findings in bone scintigraphy, orthopaedic disorders, endocrine, and neuroendocrine tumors. Therefore, the complementary use of scintigraphic and anatomic imaging modalities is expected to overcome many of the limitations also in the assessment of infection. This article discusses current scintigraphic techniques of infection imaging with particular attention to the diagnostic value of SPECT/CT.