"Abstract In the last years, new insights into the molecular basis of rheumatic conditions have been described, which have generated particular interest in understanding the pathophysiology of these diseases, in which lies the explanation of the diversity of clinical presentation and the difficulty in diagnostic and therapeutic approaches. In this review, we focus on the new pathophysiological findings for Sjögren syndrome and on the derived new SPECT and PET radiopharmaceuticals to detect inflammation of immunological origin, focusing on their role in diagnosis, prognosis, and the evaluation of therapeutic efficacy.
Conclusions The more we investigate the pathogenesis of diseases, the more we understand how to prevent and treat them. However, we also define new important molecular targets for diagnostic purposes by tailoring new radiopharmaceuticals. This strategy certainly applies to rheumatic diseases and to SS in particular, and understanding the role of several molecules, receptors, and immune cells in SS has allowed the application of specific radiopharmaceuticals for targeting these molecules and cells in vivo. Furthermore, the availability of SPECT and PET studies has offered the possibility to show in vivo the presence, homing, and trafficking of different immune cells involved in the pathogenesis of SS, providing further understanding of the pathogenetic role of these cells. Current evidence supports conducting robust studies to determine the appropriate place for molecular imaging in the diagnostic flowchart of SS and for therapy decision-making and follow-up of therapy efficacy."