Correction of Physiological Artifacts in Multi-Echo fMRI Data-Evaluation of Possible RETROICOR Implementations

10 Dec

Limitations of multiexponential T1 mapping of cortical myeloarchitecture

Neuropsychiatric malignancies frequently manifest at the level of individual cortical layers. The resolutions currently available for medical magnetic resonance imaging (MRI) prevent the study of these pathologies at clinically available field strengths of 3 T. Previous studies have claimed to have overcome these issues by extensions of quantitative MRI. Following this, the feasibility of multiexponential T1 relaxometry was assessed as a basis for in vivo delineation of cortical lamination. Three methods of non-linear least-squares-based multiexponential analysis were examined across key degrees of freedom identified in the literature. The methods employ a wide variety of ways to overcome the common pitfalls of multiexponential analysis, such as regularization, bound constraints, and repeated optimization from multiple starting points. A custom MRI phantom was 3D-printed and filled with various MnCL2 mixtures that represent the spin-lattice relaxation times that commonly occur in neocortical gray and white matter at 3 T. A 96 × 96-voxel image consisting of a single slice was acquired using a FLASH sequence and used to create 10 composite datasets with known distributions of T1 decay constants. The results showed that lowest relative error achieved across multiexponential models was approximately 20%. 

10 Dec

Ultra-refractory epilepsy: The newly described entity

Objective: Drug-resistant epilepsy (DRE) is defined as the failure of two antiseizure medications (ASMs) to achieve complete seizure control, affecting approximately 30% of epilepsy patients. In some cases, additional ASMs and surgical approaches are also unsuccessful. Ultra-Refractory Epilepsy (URE) is a newly described entity, characterized by the failure of six distinct epilepsy treatment strategies, including ASMs, surgical resection, and neurostimulation techniques. This study aimed to analyze demographic and clinical data of URE patients managed at the Brno Epilepsy Center, a member of the European Reference Network (ERN)-EpiCARE.

Methods: We conducted a retrospective cohort study with a prospective follow-up component. Adult patients hospitalized for epilepsy at the Brno Epilepsy Center between 2017 and 2023 were retrospectively identified, and their outcomes were prospectively assessed in February 2025 through medical record review and structured telephone interviews. URE patients were identified, and their demographic and clinical data were analyzed.

Results: In this study, 1034 patients' charts were reviewed, and 62 patients (6%) met the criteria for URE. In the URE cohort, the median age of epilepsy onset was 9 years (range 1-60 years), and the median age at the time of evaluation was 35 years (range 21-67 years).