New brain scan spots hidden inflammation in rare autoimmune brain disease
Researchers have developed a PET imaging technique that detects brain inflammation in anti-LGI1 autoimmune encephalitis, a rare but serious condition that damages memory and cognition. The advance could transform diagnosis and treatment monitoring, offering doctors a concrete way to track disease progression and evaluate whether therapies are working in patients often misdiagnosed for months.
Originaltitel: [18F]fluorodeprenyl-D2 PET can detect and monitor astrogliosis in anti-LGI1-IgG autoimmune encephalitis
Purpose To explore whether detecting local astrogliosis using [F-18]fluorodeprenyl-D2 ([F-18]F-DED) positron-emission-tomography (PET) uncovers and monitors inflammatory lesions in patients with anti-leucine-rich glioma-inactivated 1 antibody (LGI1-ab) associated autoimmune encephalitis (AE). Methods Dynamic [F-18]F-DED PET scans (0-60 min post-injection) were obtained from a cohort of 15 LGI1-AE patients, 9 of whom were re-examined during the disease course, and from 15 controls. PET quantification was performed by kinetic modelling with an image derived input function and calculation of simplified standardized uptake values (SUV). [F-18]F-DED SUVr (referenced to the straight gyrus) were analyzed for LGl1-AE target regions, compared between baseline and follow-up PET scans, used to investigate asymmetry of the mesial temporal lobe (MTL), and correlated to routine clinical data. Results Simplified [F-18]F-DED PET quantification of the 30-60 min time-frame showed excellent agreement with kinetic modelling of the full dynamic imaging protocol. In LGI1-AE patients, [F-18]F-DED SUVr values were significantly increased by 16% in the MTL (p = .002) and by 12% in the cerebellum (p = .014). [F-18]F-DED signals in the MTL significantly declined during the course of the disease (mean follow-up time: 15 months, p = .006). MTL asymmetry (> 5%) of [F-18]F-DED SUVr was present in 8/15 of LGI1-AE patients compared to 1/15 controls (p < .001) and showed marked decline between baseline and follow-up in LGI1-AE patients. Conclusion This pilot study shows that [F-18]F-DED PET is a promising tool to monitor regional astrogliosis in LGI1-AE patients and may provide a direct read-out of this important aspect of inflammatory disease activity.