Spine Infections: the role of Fluorodeoxyglucose Positron Emission Tomography (FDG PET) in the context of the actual diagnosis guideline

Spondylodiscitis and Its Mimickers: A Pictorial Review

Spondylodiscitis is an infection of the intervertebral disc, the adjacent vertebral body, and/or contiguous structures due to the introduction of infectious agent, usually by the hematogenous route. Imaging is crucial in assessing bacterial and tubercular spondylodiscitis, as well as their associated complications. Magnetic resonance imaging in particular can clearly depict osteo-structural changes in the vertebral body and the associated disc, as well as any soft-tissue complications, such as paravertebral abscess and/or epidural abscess, improving disease characterization and helping to recognize the agent involved. Nevertheless, other non-infectious diseases may mimic imaging appearances of spondylodiscitis and one should be aware of these conditions when interpreting MR images, which include Modic type I degenerative changes, ankylosing spondylitis, acute Schmorl's node, porotic fractures, and spinal neuropathy arthropathy. This pictorial review aims at describing imaging findings of bacterial and non-bacterial spondylodiscitis, complications, and those pathologies that mimic these infections.

The Role of 18-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography (18F-FDG PET/CT) in the Diagnosis and Evaluation of Spondylodiscitis

Spondylodiscitis, characterized by inflammation of the intervertebral disc and adjacent vertebral bodies, presents a diagnostic challenge due to its nonspecific clinical manifestations and variable imaging findings. This review examines the role of PET-CT with FDG, in the evaluation of spondylodiscitis, focusing on its utility in diagnosis, assessment of disease extent, treatment response monitoring, and prognostication. FDG PET-CT, by combining metabolic and anatomical imaging modalities, offers superior sensitivity and specificity compared to conventional imaging techniques in detecting infectious foci, distinguishing between infection and post-treatment changes, and identifying occult sources of infection. Additionally, FDG PET-CT facilitates the localization of infection, aiding in targeted biopsy and guiding surgical intervention. Moreover, quantitative PET parameters, such as standardized uptake values (SUVs), hold promise for predicting treatment response and prognosis. Despite its advantages, FDG PET-CT has limitations, including false-positive results in the setting of inflammation and limited availability in resource-constrained settings. Collaborative efforts between radiologists, nuclear medicine specialists, infectious disease specialists, and spine surgeons are essential to optimize the role of FDG PET-CT in the multidisciplinary management of spondylodiscitis. Further research is warranted to elucidate the cost-effectiveness and clinical impact of FDG PET-CT in this challenging clinical entity.