Using Nuclear Medicine Imaging Wisely in Diagnosing Infectious Diseases

Abstract

In recent years, there has been an increasing emphasis on efficient and accurate diagnostic testing, exemplified by the American Board of Internal Medicine’s “Choosing Wisely” campaign. Nuclear imaging studies can provide early and accurate diagnoses of many infectious disease syndromes, particularly in complex cases where the differential remains broad.This review paper offers clinicians a rational, evidence-based guide to approaching nuclear medicine tests, using an example case of methicillin-sensitive Staphylococcus aureus (MSSA) bacteremia in a patient with multiple potential sources. Fluorodeoxyglucose-positron emission tomography (FDG-PET) with computed tomography (CT) and sulfur colloid imaging with tagged white blood cell (WBC) scanning offer the most promise in facilitating rapid and accurate diagnoses of endovascular graft infections, vertebral osteomyelitis (V-OM), diabetic foot infections, and prosthetic joint infections (PJIs). However, radiologists at different institutions may have varying degrees of expertise with these modalities. Regardless, infectious disease consultants would benefit from knowing what nuclear medicine tests to order when considering patients with complex infectious disease syndromes.

Rabbit model of Staphylococcus aureus implant-associated spinal infection

“…soft tissue versus bone involvement). In recent years, 18 F-FDG-PET/CT is being increasingly utilized for imaging of infectious diseases ( Censullo and Vijayan, 2017 ). In general, for detection of a vertebral infection, 18 F-FDG-PET/CT imaging has a relatively high sensitivity ( Gemmel et al, 2010 ; Kouijzer et al, 2018 ).…”

“…However, since 18 F-FDG is a marker for glucose uptake, any metabolically active tissue is detected and this tracer is therefore non-specific and cannot accurately distinguish between inflammation due to infection versus that caused by non-infectious processes. In the future, novel PET-based imaging tracers specific to the pathogen or components of the inflammatory response may serve as precision medicine tools to facilitate acquisition of temporal and spatial information on infection progression, unachievable by current modalities ( Censullo and Vijayan, 2017 ; Gordon et al, 2019 ; Hammoud, 2016 ). The extent and location of infection and inflammatory response could facilitate risk stratification of patients with post-surgical IASI.…”

Molecular Imaging: a Novel Tool To Visualize Pathogenesis of Infections In Situ

“…Current radiopharmaceuticals to image infections rely on nonspecific pathophysiological consequences of infection, such as increased capillary permeability, vasodilation, and hyperemia, as well as adaptation of local metabolism (55). Similarly, while 18 F-FDG PET is a valuable tool for the diagnosis and management of infectious diseases (56), it is not specific for infection and cannot differentiate infection from other disease processes, such as inflammation or cancer. Development of pathogen-specific tracers has been challenging and, in the past, demonstrated variable results.…”

Molecular Imaging of Diabetic Foot Infections: New Tools for Old Questions

“…Gadolinium contrast T1 imaging in patients with normal renal function is a highly precise method to establish the extent of infection, as it is also able to detect the presence of secondary signs of osteomyelitis such as ulcers, sinus tracks, cellulitis, tenosynovitis, and abscesses [49]. However, these findings frequently overlap with other conditions such as trauma, healing osteonecrosis, gout, ischemia, recent surgery, and, most importantly, acute CN [51,52]. While there are some features that could help differentiate between osteomyelitis and CN (focal vs. multiple-bone involvement, location, the presence of foot deformity and secondary signs of infection), this differential diagnosis is a frequent clinical challenge in diabetic patients [52].…”