In Vivo T1-weighted Contrast MRI and 1H-MR Spectroscopy in Autoimmune Encephalitis with Cognitive Failure
Abstract number :
2.511
Submission category :
2. Translational Research / 2A. Human Studies
Year :
2023
Submission ID :
1404
Source :
www.aesnet.org
Presentation date :
12/3/2023 12:00:00 AM
Published date :
Authors :
Presenting Author: Olga Taraschenko, MD, PhD – University of Nebraska Medical Center
Lakshman Arcot Jayagopal, MD – UNMC; Audrina Mullane, PhD – UNMC; Balasrinivasa Sajja, PhD – UNMC; Matthew White, MD – UNMC; Yan Zhang, PhD – UNMC; Uberti Mariano, PhD – UNMC
Rationale:
Chronic phase sequelae of autoimmune encephalitis include seizures and persistent loss of memory and language functions, leading to long-term disability. One of the potential mechanisms of cognitive failure in chronic brain disorders was linked to the disruption of adult hippocampal neurogenesis; however, the in vivo tools to assess the stem cell pool are currently lacking. In the present study, we used the advanced imaging techniques to noninvasively assess hippocampal stem cell reserve and regional metabolite patterns in patients with cognitive loss after autoimmune encephalitis.
Methods:
Male and female patients with history of definite antibody positive autoimmune encephalitis underwent neuropsychological evaluation to assess attention, processing speed, executive functioning, language, visuoperception, and memory. Abnormal performance on a test was based on normative scores being at least 1.5 SD below the mean (z score = ≤-1.5). A cognitive domain was deemed to be a deficit based on at least one or more abnormal scores within a domain. Further, a composite cognitive score was assigned based on the overall number of affected domains as mild (1 domain), moderate (2-3) or severe (≥ 4) impairment. MRI was performed on a Siemens Prisma 3T magnet with high-density 64 channel head coils. Relative cerebral blood volume (rCBV) measurements with T1-weighted gadolinium contrast MRI, T2*-based perfusion analysis as well as quantitative single voxel1 H-MR spectroscopy (MRS) of the hippocampus and cortex were performed.
Results:
The patients (mean age 37.3 ± 10 years) who recovered from anti-NMDAR encephalitis (n=3) and leucine glioma-1 inactivated (LGI-1) encephalitis (n=1) were seizure free at the time of testing and received 0-2 anti-seizure medications with or without immunotherapy. In contrast to normal subjects (n=2) who had normal performance, 3 (75%) of encephalitis patients had the impairments of attention and processing speed functions, 2 (50%) had executive, visuospatial and memory dysfunction while one (25%) had language impairment. Overall, 75% and 25% of patients demonstrated moderate and mild impairment, respectively. The hippocampus rCBV percentage values (mean ± SD) in normal subjects and encephalitis patients were 4.37 ± 0.62 and 5.80 ± 1.15, respectively. The T2*-based relative corrected hippocampal BV in the same groups were 1.0 ± 0.1 and 1.1 ± 0.4, respectively. The mean ± SEM concentrations of N-acetyl-aspartate (NAA), total choline (tCho), total creatine (tCr), myoinositol (mI) and glutamate-glutamine complex (Glx) in the hippocampus of encephalitis patients were 7.4 ± 0.1, 1.8 ± 0.1, 6.1 ± 0.3, 7.1 ± 0.2 and 7.6 ± 0.1 [mM]. The corresponding values in the cortex were 9.4 ± 0.3, 1.7 ± 0.1, 6.2 ± 0.2, 5.8 ± 0.2, 7.9 ± 0.6 [mM].
Conclusions:
These findings support the feasibility of noninvasive monitoring of rCBV and regional metabolite levels in the hippocampus and cortex of patients with encephalitis and cognitive impairment; these measurements can be applied longitudinally. In the expanded cohort, this approach can be used to assess the correlation of imaging parameters with degree of cognitive loss or seizure burden.
Funding:
DHHS LB606 Nebraska Stem Cell Grant.
Translational Research