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Updated: Jun 11, 2026
Co-analysis of Brain Structure and Function using fMRI and Diffusion-weighted Imaging
Published on: November 8, 2012
Beyond structural MRI: combined diffusion metric improve delineation of epileptogenic tissue in focal cortical
David Kala1,2, Timur Abragimovich1,3, Radek Janča3,2
1Department of Pathophysiology, Second Faculty of Medicine, Charles University, Plzeňská 311, 150 06, Prague 5, Czech Republic.
Abstract:
Accurate delineation of the epileptogenic zone in focal cortical dysplasia (FCD) remains challenging, as structural MRI often underestimates the extent of dysplastic tissue. Diffusion MRI can probe microstructural alterations, yet individual diffusion models provide limited sensitivity and clinical interpretability. We prospectively studied 19 patients with histologically confirmed FCD who underwent presurgical evaluation, surgical resection, and postsurgical MRI. Fourteen diffusion metrics derived from complementary diffusion models were integrated using logistic regression to generate a single combined diffusion metric (CDM). Spatial correspondence among structural MRI, resected tissue, perilesional cortex, and contralateral homologues was assessed using Dice similarity and ROC analyses. Histological cellularity and multimodal imaging data were used for biological validation. Individual diffusion metrics identified microstructural abnormalities within MRI-visible lesions, including reduced anisotropy, lower fibre density, and increased isotropic diffusion. Integration into the CDM improved discrimination between lesional and healthy tissue (p < 0.03), detected abnormalities extending beyond radiological borders, and showed spatial concordance with FDG-PET hypometabolism and epileptiform activity in 90% of patients. CDM-guided delineation increased agreement with resected regions and reduced unresected perilesional volume. CDM provides a biologically grounded and clinically interpretable representation of epileptogenic tissue in FCD, refining presurgical mapping beyond conventional MRI and potentially improving surgical targeting.
Insights
A new combined diffusion metric (CDM) improves the detection of the epileptogenic zone in focal cortical dysplasia (FCD) by integrating multiple diffusion MRI models. This refined imaging approach enhances surgical targeting for better patient outcomes.
Area of Science:
- Neuroimaging
- Epilepsy Research
- Medical Physics
Background:
- Accurate delineation of the epileptogenic zone in focal cortical dysplasia (FCD) is crucial for successful epilepsy surgery.
- Conventional structural MRI often underestimates the extent of FCD, complicating surgical planning.
- Individual diffusion MRI models have limitations in sensitivity and clinical interpretability for FCD.
Purpose of the Study:
- To develop and validate a combined diffusion metric (CDM) integrating multiple diffusion models for improved epileptogenic zone delineation in FCD.
- To assess the spatial concordance of the CDM with histological findings and other neuroimaging modalities.
- To evaluate the clinical utility of CDM in refining presurgical mapping and surgical targeting for FCD.
Main Methods:
- Prospective study of 19 patients with histologically confirmed FCD undergoing presurgical evaluation and surgical resection.
- Integration of 14 diffusion metrics from complementary diffusion models into a single CDM using logistic regression.
- Assessment of spatial correspondence using Dice similarity and ROC analyses, validated with histological cellularity and multimodal imaging data.
Main Results:
- Individual diffusion metrics revealed microstructural abnormalities within MRI-visible lesions.
- The CDM significantly improved discrimination between lesional and healthy tissue (p < 0.03).
- CDM detected abnormalities extending beyond radiological borders and showed 90% concordance with FDG-PET hypometabolism and epileptiform activity.
Conclusions:
- The combined diffusion metric (CDM) offers a biologically grounded and clinically interpretable method for characterizing epileptogenic tissue in FCD.
- CDM refines presurgical mapping beyond conventional MRI, potentially improving surgical targeting and patient outcomes.
- This integrated diffusion MRI approach enhances the delineation of the epileptogenic zone in FCD.
