Abstract Details

Title MR Perfusion in the Workup of NMDA Receptor Encephalitis

Topic Autoimmune Neurology

Presentation(s) P3 - Poster Session 3 (11:30 AM-12:30 PM)

Poster/Presentation
Number 1-026

Objective Assess the utility of MR perfusion in the diagnosis of NMDA receptor autoimmune encephalitis.

Background Autoimmune encephalitis (AE) is frequently misdiagnosed, contributing to treatment delays and poor outcomes. Standard brain MRI is abnormal in approximately 50% of patients, often even less in NMDA encephalitis. In contrast to MRI, positron emission tomography (PET) scans are more sensitive, with findings in up to 99% of cases. PET, however, is not widely available, costly, and exposes patients to radiation. Similar to PET, MR perfusion imaging characterizes regional blood flow, perhaps representing an accessible alternative to PET to aid in early diagnosis of AE.

Design/Methods We conducted a retrospective analysis of confirmed NMDAR+ encephalitis cases from Stanford Research Repository (STARR) database. Rstudio was used for descriptive and inferential analyses. Firth’s penalized logistic regression was used to examine potential association between MR perfusion abnormalities and APEII scores, seizures, ICU admission or age.

Results Of 17 NMDA cases, 16 cases had MR perfusion studies, 50% of which were abnormal. Amongst those, 50% had normal FLAIR sequences. PET scans were performed in 11 cases, 4 of which were positive. Amongst these positive cases, 3/4 had MRI perfusion abnormalities, 2 out of 3 of which matched the abnormal region on PET. There were no significant associations between the presence of a perfusion abnormality and APEII score, age, ICU admission, or seizures (p>0.05).

Conclusions 50% of NMDA patients had MR perfusion changes. Notably, half of these cases had negative MRI sequences otherwise. Only a small proportion of PET studies were positive, the majority of which had MR perfusion abnormalities. These findings support use of MR perfusion in AE workup, especially when conventional MRI is unrevealing. Future analyses will assess the utility of MR perfusion as a tool to discriminate AE cases through a blinded-imaging re-analysis of cases and age matched controls.

Authors/Disclosures
Abby Scurfield, MD PRESENTER	Dr. Scurfield has nothing to disclose.
Kristin M. Galetta, MD, FAAN (Stanford University)	Dr. Galetta has received personal compensation in the range of $0-$499 for serving as a Speaker with Can Do MS.
Bryan Lanzman, MD	Dr. Lanzman has nothing to disclose.
Rachelle Dugue, MD, PhD	Dr. Dugue has nothing to disclose.

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