No Change in Network Connectivity Measurements with Shorter Resting fMRI Acquisition Times
Abstract number :
3.504
Submission category :
3. Neurophysiology / 3G. Computational Analysis & Modeling of EEG
Year :
2023
Submission ID :
1491
Source :
www.aesnet.org
Presentation date :
12/4/2023 12:00:00 AM
Published date :
Authors :
Presenting Author: Elliot Neal, MD – University of South Florida
Keaton Piper, MD – University of South Florida; Samantha Schimmel, BS – University of South Florida; Adam Alayli, BS – University of South Florida; Zeegan George, BS – University of South Florida; Molly Monsour, BS – University of South Florida; Gavin Lockard, BS – University of South Florida; Stephanie MacIver, MD – University of South Florida; Fernando Vale, MD – Augusta Health; Yarema Bezchlibnyk, MD, PhD – University of South Florida
Rationale:
Success of epilepsy surgery for patients with medically refractory epilepsy relies on correct localization of the epileptogenic zone via preoperative planning using electroencephalograms (EEG), structural magnetic resonance imaging (MRI), and resting state functional MRIs (rsfMRI). Traditional rsfMRI acquisition protocols rely on longer acquisition times, sometimes upwards of 20 to 30 minutes which can be expensive and impractical in a normal clinical practice. In this study we aim to validate our center’s five minute rsfMRI acquisition protocol by comparing network connectivity data generated using five minutes of rsfMRI data to data generated from 10 minutes of scan time, hypothesizing that the data collected will not differ between both time-frames.
Methods:
A series of patients with medically refractory temporal lobe epilepsy underwent a standard pre-surgical evaluation for epilepsy surgery, including MRI, video-EEG, Wada testing, 18F-FDG PET, and neuropsychological testing. Two five minute rsfMRI sessions were included before and after each MRI session. The first five minute scan was used in a network modeling algorithm and compared to data generated from the two five minute scans stitched together to make a single 10-minute scan. These were combined with scalp EEG data to generate a positively and negatively correlated epilepsy network consisting of a collection of image voxels presumed to be included in a network including the epileptogenic zone. Continuous variables were compared using two-sample paired t-tests.
Results:
Fourteen MRI sessions were used in this analysis, evenly distributed among male and female patients. Twelve patients (86%) presented with temporal lobe epilepsy and the remaining patients had epilepsy associated with a lesion identified on MRI. 6 sessions (43%) were from patients who had left-sided surgery and the remainder were on the right side (57%). Surgeries consisted of laser interstitial thermal therapy for amygdalohippocampotomy (57%), hippocampal sparing amygdalohippocampectomy (14%), lesion resection (14%), and anterior temporal lobectomy (14%). There was no difference found between 5 and 10 minute networks in average connectivity across the whole brain (p=0.1751), the hemisphere ipsilateral to the surgery (p=0.3561), or the hemisphere contralateral to the surgery (p=0.3275). There was no difference between scans in the number of voxels, average connectivity, or spread in the positively (p=0.4239, p=0.8323, p=0.6416 respectively) or negatively correlated networks (p=0.4163, p=0.8218, p=0.9187, respectively).
Conclusions:
There is no significant difference in measured parameters between 5 and 10 minute rsfMRI sequences. A five minute sequence may be adequate to assess global network connectivity relating to epileptogenic networks. Future studies will aim to further control variables involved in EEG and MRI acquisition to form a reproducible network model useful for planning epilepsy surgeries and developing more insight into surgical outcomes.
Funding: None.
Neurophysiology