Assessing Alterations in Thalamic Fiber Integrity After Temporal Lobe Epilepsy Resection: Impact of Clinical Factors
Abstract number :
1.343
Submission category :
5. Neuro Imaging / 5A. Structural Imaging
Year :
2025
Submission ID :
935
Source :
www.aesnet.org
Presentation date :
12/6/2025 12:00:00 AM
Published date :
Authors :
Presenting Author: Kaiser Williams, Undergraduate Student – Vanderbilt University
Lucas Sainburg, BS – Vanderbilt University
Dario Englot, MD PhD – Vanderbilt University Medical Center
Kurt Schilling, PhD – Vanderbilt Institute of Imaging Science
Victoria Morgan, PhD – Vanderbilt University Medical Center
Rationale: The thalamus plays a significant role in seizure propagation in temporal lobe epilepsy (TLE). In drug-resistant TLE, resection of the epileptogenic focus—via selective amygdalohippocampectomy (SAH) or anterior temporal lobectomy (ATL)—can lead to improved seizure control. However, the effects of these procedures on thalamic structure remain unclear. Thalamic fibers can be measured using fixel-based analysis of diffusion-weighted MRI (DWI), a method that quantifies distinct fiber populations within a voxel by deriving parameters such as fiber density and cross sectional area (FDC).1 Here, we aim to assess changes in thalamic fiber integrity due to TLE resection and evaluate the effects of postoperative progression, resection type (SAH vs ATL), and preoperative epilepsy duration on these changes.
Methods: This study included 30 healthy controls and 44 patients with unilateral TLE (30 right) who underwent SAH (n = 34) or ATL. All subjects underwent a T1-weighted scan and DWI (2.5x2.5x2.5 mm3, 92 directions, b = 1600 s/mm2) on a 3T MRI. Controls were scanned once, and patients were scanned before and after resection.
Spherical deconvolution estimated the fiber orientation distribution (FOD) at each voxel of the DWI. Controls were used to create an FOD template to which patient FODs were registered (Fig 1, top). Thalamic FODs were segmented into fixels in which FDC was computed to represent the total axonal integrity of each fiber population (Fig 1, middle).1 A general linear model compared thalamic FDC from pre- to post-resection using MRtrix32, including covariates for preoperative epilepsy duration, resection type (SAH vs. ATL), and time elapsed since resection (Fig 1, bottom).
Results: Post-resection FDC decreases were observed in lateral-oriented fixels of the ipsilateral ventral/pulvinar regions in right- and left-sided resection (pFWE < 0.05, Fig 2A). Longer times post-resection trended with FDC decreases primarily in lateral-oriented fixels of ipsilateral ventral/pulvinar regions (p
Neuro Imaging