New 7T MRI technique pinpoints hidden epilepsy-causing brain lesions

Editor's Note

A newly refined 7T MRI imaging technique may significantly improve outcomes for people with hard-to-treat focal epilepsy by revealing tiny brain lesions that standard imaging methods often miss, HealthDay March 26 reports from a new study published in the journal Epilepsia. Researchers achieved this advance by implementing “parallel transmit,” an approach in which multiple radiofrequency transmitters are placed around the patient’s head to eliminate signal blackspots—a common problem in high-field MRI scans. This breakthrough offers new hope to patients whose epilepsy does not respond to medication and whose underlying lesions remain undetected by conventional scans.

Focal epilepsy occurs when seizures originate from a misfiring cluster of neurons in the brain. While some of these areas can be surgically removed or treated with targeted procedures, identifying the precise source of the problem is crucial for success. Although standard MRI systems typically operate at a magnetic field strength of 3T, 7T scanners can, in theory, deliver more detailed images. However, 7T imaging has historically produced “dead zones” in parts of the brain—especially the temporal lobes—due to uneven radiofrequency transmission.

Using the parallel transmit method, researchers overcame these blind spots by employing eight transmitters instead of a single transmitter. They tested the enhanced approach on 31 patients with drug-resistant focal epilepsy. The results:

• In nine patients, the parallel transmit 7T MRI uncovered previously hidden lesions
• In four more, it confirmed lesions that were merely suspected on earlier scans
• In another four patients, the new images showed that once-suspected lesions were not the cause of their seizures after all.

Overall, the improved imaging findings prompted a change in clinical management for 18 of the 31 patients studied. Nine were considered good candidates for surgery to remove their lesions, and one underwent laser surgery. Three had lesions so complex that surgery was not feasible, while five received alternative techniques involving implantable electrodes that can help both localize and treat seizure activity.

Experts highlight that such high-resolution, targeted imaging can help more patients become eligible for potentially curative interventions. As 7T MRI technology continues to evolve and become more widely available, this parallel transmit approach may help guide neurosurgical options and reduce the burden of epilepsy for a growing number of patients.