In vivo 9.4 Tesla MRI of a patient with drug-resistant epilepsy: Technical report

Purpose: In resective epilepsy surgery for drug-resistant focal epilepsy (DRE), good seizure outcome is strongly associated with visualization of an epileptogenic lesion on MRI. Standard clinical MRI (≤ 3 Tesla (T)) may fail to detect subtle lesions. 7T MRI enhances detection and delineation, the potential benefits of increasing field strength to 9.4T are explored.

Methods: A 36 years old male patient with DRE evaluated for resective surgery, in which 3T and 7T MRI failed to detect any epileptogenic lesions, was submitted to a dedicated epilepsy scan protocol using T1 and T2* weighted imaging at 9.4T. Images were evaluated independently by two neuroradiologists and one neurosurgeon.

Results: 9.4T MRI offered increased spatial resolution and enhanced depiction of anatomical structures vital for epilepsy imaging, exemplified by regions mesio-temporal (hippocampus, amygdala), latero-temporal, insula, frontal and temporal operculum, and gray-white matter junction (precentral gyrus/frontal lobe) compared to 3T and 7T, albeit with challenges in mesial-temporal and antero-inferior temporal lobe imaging. No epileptogenic lesion was identified.

Conclusion: 9.4T demonstrates promise in the identification and delineation of anatomical structures and small epileptogenic lesions in patients with DRE eligible for resective surgery. Whether clinical 9.4T MRI in DRE has clinical advantages over 7T or leads to a more complete resection of the epileptogenic zone and improved seizure outcome after epilepsy surgery needs to be established.