Creation of Personalized Node Abnormality Maps in Temporal Lobe Epilepsy
Abstract number :
3.264
Submission category :
5. Neuro Imaging / 5B. Functional Imaging
Year :
2022
Submission ID :
2204509
Source :
www.aesnet.org
Presentation date :
12/5/2022 12:00:00 PM
Published date :
Nov 22, 2022, 05:25 AM
Authors :
Jordyn Herrington, – Vanderbilt University; Lucas Sainburg, BS – Biomedical Engineering – Vanderbilt University; Andrew Janson, PhD – Department of Radiology and Radiological Sciences – Vanderbilt University Medical Center; Graham Johnson, BS – Biomedical Engineering – Vanderbilt University; Baxter Rogers, PhD – Department of Radiology and Radiological Sciences – Vanderbilt University Medical Center; Dario Englot, MD, PhD – Department of Neurological Surgery – Vanderbilt University Medical Center; Victoria Morgan, PhD – Radiology and Radiological Sciences – Vanderbilt University Medical Center
Rationale: Drug-resistant focal epilepsy is characterized by the presence of recurrent seizures and commonly treated through resection of the focus. The success of this surgery on mitigating epileptic symptoms is highly dependent on the identification of the focus and abnormal regions in an individual patient. Thus, we created personalized node abnormality maps by comparing age-corrected functional (FC) and structural (SC) connectomes of patients with focal epilepsy to a population of controls. To examine our abnormality measures, we compared groups of right and left mesial temporal lobe epilepsy (mTLE) patients to controls.
Methods: A total of 31 right mTLE and 16 left mTLE patients and 48 healthy controls underwent a 3T MRI including T1-weighted scan (1x1x1 mm3), two 10 min resting-state functional MRI scans (TR = 2 s, 3x3x4 mm3), and diffusion-weighted imaging (DWI, 2.5x2.5x2.5 mm3, 92 directions, b = 1600 s/mm2). FC and SC were computed and converted to standard deviations from age-matched controls across 117 regions as in [1]. One set of controls (n=20) was imaged twice within six weeks, and the difference between the two was used as a measure of connectome variability. An abnormal connection was defined as three standard deviations above and below the mean variability. Patient matrices were binarized with according to this threshold, edges returning a one if they were abnormal. The total abnormality value for each node was calculated by summing all its edges. These threshold matrices were also applied to the second cohort of controls (n=28). A two-tailed unpaired t-test was performed to find regions that had significant increases in abnormal nodes across patients when compared to the controls. This was completed for both FC and SC.
Results: A functional node abnormality map for an individual left mTLE patient is shown in Figure 1. Results of the two-tailed unpaired t-test showed increases in node abnormality values in left mTLE patients in the left central operculum and the right orbital part of the inferior frontal gyrus for FC and the left temporal pole and the left anterior hippocampus for SC (p < 0.001, uncorrected, Figure 2A). For right mTLE patients, the t-test showed a decrease in node abnormality in the left and right temporal pole for FC, while no significant differences were found for SC (p < 0.001, uncorrected, Figure 2B).
Neuro Imaging