Normal distribution of 18F-FDG in the spinal cord: a systematic review

Background: In the current systematic review, given the importance of recognition of the normal distribution of 18F-FDG in the PET/CT imaging for accurate interpretation, especially in oncologic patients, we interested in investigating the 18F-FDG normal uptake throughout the spinal cord.Methods: A comprehensive search of the literature on the physiologic patterns of 18F-FDG distribution in the spinal cord was carried out. Herein, we performed a qualitative analysis of the 18F-FDG avidity in cervical, thoracic and lumbar levels of the spine.Results: 12 studies comprising 1172 patients were enrolled in our qualitative analysis. These investigations showed discrepancies in location, size, number, and intensity of 18F-FDG uptake throughout the spinal cord. However, the obtained results endorsed that the 18F-FDG avidity was higher in the lower thoracic spine (T11-12). Moreover, a decreasing trend in 18F-FDG uptake was observed from cervical to lumbar levels.Conclusion: On 18F-FDG-PET/CT imaging incidental focal hyper metabolism of the spinal cord at the level of lower thoracic vertebrae could be due to physiologic 18F-FDG uptake, and should be not be mistaken with metastasis in the oncologic patients. This issue needs more clarification in subsequent studies.