ABSTRACT
This multicenter study aims to provide a qualitative and consensual description of brain 18 F-FDG PET images in patients with suspected neurological long COVID, regarding the previously reported pattern involving olfactory bulbs and other limbic/paralimbic regions, as well as the brainstem and cerebellum. Methods: From the beginning of August 2021 to the end of October 2021, brain 18 F-FDG PET exams of patients referred for suspected neurological long COVID with positive reverse transcription polymerase chain reaction (RT-PCR) and/or serology for the SARS-CoV-2 infection were retrospectively reviewed in three French Nuclear Medicine departments. Experimented nuclear physicians from each department had to classify according to the same visual interpretation analysis brain 18 F-FDG PET scans as being normal, mildly to moderate (incomplete or moderately hypometabolic), or severely affected within the previously reported long COVID hypometabolic pattern. Results: On the 143 brain 18 F-FDG PET performed during this period 3 months, 53% of scans were visually interpreted as normal, 31% as mildly to moderate and 16% as severely affected according to the COVID hypometabolic pattern. Importantly, this specific hypometabolic pattern is reported as identical in the three Nuclear Medicine departments. Typical illustrative examples are provided to help nuclear physicians in the interpretation of long COVID pattern. Conclusion: The proposed PET metabolic pattern is easily identified at visual interpretation in clinical routine in part of patients with suspicion of neurological long COVID, requiring special consideration for fronto-basal paramedian regions, the brainstem and cerebellum.