Nuclear Imaging of Bacterial Infection: The State of the Art and Future Directions

Abstract

Learning Objectives: On successful completion of this activity, participants should be able to describe (1) the clinical justifications for using nuclear medicine techniques in imaging bacterial infections; (2) the mechanisms of nuclear imaging methods used to detect bacterial infections; and (3) the bacterial-metabolism specific imaging techniques currently under development. Financial Disclosure: Dr. Ohliger travels and speaks for General Electric. The authors of this article have indicated no other relevant relationships that could be perceived as a real or apparent conflict of interest. CME Credit: SNMMI is accredited by the Accreditation Council for Continuing Medical Education (ACCME) to sponsor continuing education for physicians. SNMMI designates each JNM continuing education article for a maximum of 2.0 AMA PRA Category 1 Credits. Physicians should claim only credit commensurate with the extent of their participation in the activity. For CE credit, SAM, and other credit types, participants can access this activity through the SNMMI website (http://www.snmmilearningcenter.org) through December 2023. Increased mortality rates from infectious diseases is a growing public health concern. Successful management of acute bacterial infections requires early diagnosis and treatment, which are not always easy to achieve. Structural imaging techniques such as CT and MRI are often applied to this problem. However, these methods generally rely on secondary inflammatory changes and are frequently not specific to infection. The use of nuclear medicine techniques can add crucial complementary information, allowing visualization of infectious pathophysiology beyond morphologic imaging. This review will discuss the current structural and functional imaging techniques used for the diagnosis of bacterial infection and their roles in different clinical scenarios. We will also present several new radiotracers in development, with an emphasis on probes targeting bacteria-specific metabolism. As highlighted by the current coronavirus disease 2019 epidemic, caused by the novel severe acute respiratory syndrome coronavirus 2, similar thinking may apply in imaging viral pathogens; for this case, prominent effects on host proteins, most notably angiotensin-converting enzyme 2, might also provide worthwhile imaging targets.

Deuterium Metabolic Imaging—Rediscovery of a Spectroscopic Tool

“…The development of metabolic tools that allow detections of bacteria-specific metabolism in a specific and noninvasive fashion has been an ongoing interest for many research groups. In the last decade, several agents have been developed that explicitly target bacteria-specific metabolic pathways, especially using clinically translatable nuclear imaging technologies such as PET [ 42 ]. Magnetic resonance studies targeting bacteria-specific metabolism have been infrequently reported.…”

“…In addition, the high abundance (99.98%) and sensitivity (highest gyromagnetic ratio) of the hydrogen nucleus has led to rapid evolution of tools for 1 H NMR including many spectroscopic methods that are now integrated into routine clinical practice, especially for the characterization of prostate tumors [ 33 , 34 ], brain tumors [ 35 , 36 , 37 ], and various other metabolic derangements [ 38 , 39 , 40 ]. As far as other metabolic imaging tools, PET has also been extraordinarily successful especially with the rapid proliferation of metabolite-derived tracers and the expansion of dual modality scanners (i.e., PET-CT and PET-MR) [ 41 , 42 , 43 , 44 ]. Finally, imaging of other stable isotopes (i.e., 13 C) has benefitted from dynamic nuclear polarization (DNP) [ 45 , 46 ], where the nuclear polarization (and therefore the MR signal) is transiently increased by several orders of magnitude prior to injection.…”

Lack of Clinical Utility of Labeled White Blood Cell Scintigraphy in Patients With Fever of Unknown Origin

“…There has been increasing interest recently regarding FDG PET-CT for imaging infections [ 25 ] [ 26 ], including enthusiastic publications regarding its application to FUO [ 27 ]. When the 2 techniques were compared directly or indirectly in a relatively small number of patients with FUO, FDG PET-CT outperformed WBCS [ 28 , 29 ].…”

Radiolabeling, characterization, and preclinical evaluation of plazomicin: A potential tracer for bacterial infection

“…Bacterial infection remains a serious worldwide concern being one of the significant causes of morbidity and mortality (Polvoy et al, 2020). In recent years, the issue escalated by the accelerated emergence of multidrug‐resistant pathogens due to inappropriate and/or overuse of antibiotics (El‐kawy et al, 2016; Karaiskos et al, 2019).…”