[The use of low-field MRI for visualization of epileptogenic brain lesions in children]

To analyze MR-images of patients with focal epilepsy using a method close to the protocol of epileptic scanning on a MRI-device with the magnetic field tension of 0.4 Tesla.

MRI data of 50 children who underwent examination due to difficult-to-treat or drug-resistant forms of focal epilepsy were analyzed. MRI study was conducted using open-ended device of static magnetic field HITACHI 'APERTO' with the magnetic field tension of 0.4 Tesla. The thickness of the slices and the scan step was performed at 3.0 and 3.5 mm with the use of special positioning of slices in the coronal and axial projections, T2, T1, STIR, FLAIR weighted images (WI) perpendicular and parallel to the long axis of the hippocampus.

Potentially epileptogenic structural changes were identified in 37 patients. Abnormalities of brain development of different severity were identified in 16 patients. In 21 cases, the changes were due to the consequences of cerebral vascular catastrophes, neuroinfections, brain traumas affecting the cortical plate. A method close to the epileptic scanning protocol allowed the identification of signs of acute cerebral catastrophes in two patients. In 8 patients, potentially epileptogenic changes after false-negative descriptions of the results of previous MRI studies were newly identified. The most difficult for the diagnosis was the visualization of small structural changes in mediobasal regions of the temporal lobes. Confirmation of this supposition according to the recommended thorough investigation was obtained only in 5 out of 12 patients with suspected small-bore pathological changes in mediobasal temporal regions.

Low-tension technique approximated to the epileptic scanning protocol does not allow the reliable diagnosis of small and similar in signal characteristics changes in the visualization of mediobasal temporal lobes regions. It was not possible to reliably differentiate some cortical-subcortical neoplastic formations from various forms of focal cortical dysplasia.