Single-photon emission computed tomography-computed tomography in imaging infection.

This review focuses on the current evidence available on the use of single-photon emission computed tomography-computed tomography (SPECT-CT) in infection imaging. The single-photon functional agents commonly used to image infection include In-111-labelled or Tc-99m-labelled leucocytes, Ga-67 citrate, Tc-99m-biphosphonates and radiolabelled antigranulocyte antibodies. Although many of these agents have been available for a long time, the development of hybrid SPECT-CT technology has led to a wider use of these agents. This review shows that the application of CT to single-photon imaging techniques for imaging infection can significantly improve the accuracy of the technique by increasing the specificity and better defining the location and extent of suspected disease. Hybrid fusion images also increase the confidence of the individual in reporting and seem to be applicable to a wide range of clinical situations. We believe that, overall, SPECT-CT, by providing a clearer assessment of whether infection is present and an accurate localization of the disease so that optimum treatment can be initiated, has a role in infection imaging.