Page 184 - MEGIN Book Of Abstracts - 2023

Recruitment goals were to study 20 patients on-site at Baillet, Sylvain; Dudley, Roy W R
BCH, 10 with iNTD, and 25 as a standard-of care cohort.
McConnell Brain Imaging Center, Montreal Neurological
RESULTS At this half-way point of this longitudinal Institute, McGill University, Montréal; Philips Canada, MRI
study, 28 subjects have been recruited (57% female, Research Department, Montréal; and Departments of; Adult
mean 9 years, range 18 months-40 years). Epilepsy is and Pediatric Pathology; Pediatric Neurosurgery; Pediatric Ra-
present in half and increases in incidence and severity, diology, and; Neonatology, McGill University Health Network,
as do psychiatric symptoms, in adolescence and adult- Montréal, Quebec, Canada
hood. The average Full Scale IQ (FSIQ) was 53 (Verbal
score of 56, Non Verbal score of 49), and half scored OBJECTIVE The authors sought to assess the utility
as having ASD. Although there was no correlation of arterial spin labeling (ASL) perfusion 3T-MRI for the
between gene variant and phenotypic severity, there presurgical evaluation of poorly defined focal epilepsy
were extreme cases of lowest functioning in one indi- in pediatric patients.
vidual and highest in another that may have genotype-
phenotype correlation. The most common EEG finding METHODS Pseudocontinuous ASL perfusion 3T-MRI
was mild background slowing with rare epileptiform was performed in 25 consecutive children with poorly
activity, whereas high-density EEG and magnetoen- defined focal epilepsy. ASL perfusion abnormalities
cephalography showed reduction in the gamma fre- were detected qualitatively by visual inspection and
quency band consistent with GABAergic dysfunction. quantitatively by calculating asymmetry index (AI)
MR spectroscopy showed elevations in the GABA/NAA maps and significant z-score cluster maps based on
ratio in all regions studied with no crossover between successfully operated cases. ASL results were prospec-
subjects and controls. tively compared to scalp EEG, structural 3T-MRI, FDG-
PET, ictal/interictal SPECT, magnetoencephalography
CONCLUSIONS The SSADH Natural History Study is (MEG), and intracranial recording results, as well as the
providing a unique opportunity to study the complex final surgically proven epileptogenic zone (EZ) in oper-
pathophysiology longitudinally and derive electro- ated patients who had at least 1 year of good (Engel
physiologic, neuroimaging, and laboratory data for class I/II) seizure outcome and positive histopathology
correlation and to serve as biomarkers for clinical trials results.
and prognostic assessments in this ultra-rare inherited
disorder of GABA metabolism. RESULTS Qualitative ASL perfusion abnormalities
were found in 17/25 cases (68%), specifically in 17/20
Keywords: epilepsy, genetics, inborn errors of metabolism, MRI-positive cases (85.0%) and in none of the 5 MRI-
intellectual disability, metabolism, neuroimaging negative cases. ASL was concordant with localizing
scalp EEG findings in 66.7%, structural 3T-MRI in 90%,
Journal of child neurology (2021), Vol. 36, No. 13-14 FDG-PET in 75%, ictal/interictal SPECT in 62.5%, and
(33393837) (4 citations) MEG in 75% of cases, and with intracranial recording
results in 40% of cases. Eleven patients underwent
surgery; in all 11 cases the EZ was surgically proven by
The utility of arterial spin labeling in the presurgical positive histopathology results and the patient having
evaluation of poorly defined focal epilepsy in at least 1 year of good seizure outcome. ASL results
children (2020) were concordant with this final surgically proven EZ
in 10/11 cases (sensitivity 91%, specificity 50%). All
Lam, Jack; Tomaszewski, Patricia; Gilbert, Guillaume; 10 ASL-positive patients who underwent surgery had
Moreau, Jeremy T; Guiot, Marie-Christine; Albrecht, positive surgical pathology results and good long-term
Steffen; Farmer, Jean-Pierre; Atkinson, Jeffrey; Saint- postsurgical seizure outcome at a mean follow-up of 39
Martin, Christine; Wintermark, Pia; Bernhardt, Boris; months. Retrospective quantitative analysis based on

 ontents  Index 163
C