The Role of [18F]FDG PET Imaging for the Assessment of Vegetative State or Unresponsive Wakefulness Syndrome: A Systematic Review

Background: Different evidence on the ability of [18F] fluorodeoxyglucose ([18F]FDG) positron emission tomography (PET) imaging to assess patients in the vegetative state (VS) or unresponsive wakefulness syndrome (UWS) has been reported. Therefore, this systematic review aimed to synthesize the existing literature on this topic. Methods: A wide literature search of the PubMed/MEDLINE, Scopus, and Embase databases was conducted to find relevant published articles investigating the role of [18F]FDG PET imaging in the assessment of VS/UWS. Results: Thirty-seven studies were included in the review, and the main fields of application of this imaging modality in these patients were the evaluation of hypometabolic patterns, differentiation of disorders of consciousness (DOC), prognostic value, and ability to assess the response to particular stimuli. Conclusions: The possible role of [18F]FDG PET imaging in the assessment of VS/UWS has emerged, in particular in the differential diagnosis of other DOC or prognosis. Some insights into its value in stimulation response and therapy evaluation have also been proposed. Standardization of protocols and larger prospective studies are needed to strengthen these clinical recommendations.