Getting Small Is Suddenly Very Big: Review of the Proceedings of the Third Annual Meeting of the Society for Molecular Imaging

Abstract

he field of molecular imaging, defined here as imaging that provides information on cellular processes and molecular pathways in vivo, is rapidly growing. In this context, the term “molecular imaging” has been used for barely a decade and, until recently, few radiologists were aware of the term. The remarkable progress occurring during this short interval is, quite literally, leading to a revolution in thought. Anatomic imaging is being replaced by functional imaging, in which the underlying biochemical pathways can be directly interrogated to confirm the presence or absence of pathology. It is clear that many new techniques and insights gained from molecular imaging in animal models will play a role in imaging of human disease processes. However, which applications will bear fruit, and when, remain unclear. In the past few years, many scientific societies have formed to advance molecular imaging techniques. One of the major ones, the Society for Molecular Imaging (SMI), founded in 2000, held its third annual meeting September 9–12, 2004, in St. Louis, MO. The mission of the SMI is “to advance our understanding of biology and medicine through noninvasive in vivo investigation of cellular molecular events involved in normal and pathologic processes” [1]. Attendance at SMI’s annual meetings has grown significantly during the society’s short history. The first meeting in 2002 drew approximately 550 attendees; in 2004, the meeting had approximately 850 registrants. The goal of the 2004 meeting, to highlight the increasing ability to view disease processes in vivo, was accomplished through six plenary sessions, 16 symposia, two seminars, and more than 100 oral presentations. In addition, more than 300 posters were presented during two sessions. The meeting was called to order by David Piwnica-Worms, Washington University School of Medicine, after which Britton Chance, University of Pennsylvania, delivered the keynote lecture. This review highlights the presentations that are likely to be of special interest to radiologists. Those seeking more information should visit SMI’s Web site [1]. In his presentation, “How to Integrate ‘Molecular Imaging’ into Clinical Radiology,” King Li, National Institutes of Health, addressed the misconception that molecular imaging is an esoteric topic that will not contribute significantly to radiologic imaging of humans. Li defined molecular imaging as “the practice of medical imaging in an era of molecular medicine,” a description that should arouse the interest of radiologists in the field. He outlined the preliminary steps radiologists can take while they await the transition of molecular imaging from the animalimaging environment to the clinical-human environment. The first step is to understand the molecular biology that underlies the morphologic features seen on conventional imaging studies. The next step is to combine imaging information with the molecular diagnostic information available through numerous sources. One of the more interesting presentations explained how molecular imaging can advance our understanding of a common disease process—bone metastases from a remote primary tumor. Because development of metastases in bone marrow is dependent on expression of various growth factors normally released during bone resorption, therapies aimed at pharmacologic interference with bone turnover would be expected to decrease the rate of formation of these metastases. Several investigators are examining methods for early detection of bone metastases and assessment of therapies aimed at slowing the rate of formation. In “Optical Imaging in Early De-