Detailed imaging may improve surgical outcomes in epilepsy

Key takeaways:

• More rapid detection of subtle lesions associated with epilepsy is likely to boost surgical outcomes.
• Detailed imaging may provide the best path toward quicker lesion discovery.

LOS ANGELES — The ability to utilize more detailed imaging options, as well as to use certain imaging concurrently to detect epileptogenic lesions during presurgical consultation, may lead to better outcomes for patients, according to a speaker.

“There are some changes that have happened in our thinking over the last few years. So, how does it help to find this lesion?” Sara K. Inati, MD, head of the neurophysiology of epilepsy unit at the NIH’s National Institute of Neurological Disorders and Stroke, said in her presentation at the American Epilepsy Society annual meeting.

At times, lesions within the brain that indicate a patient has epilepsy — particularly after a new-onset seizure — are difficult to locate. While a head CT should be the first-line identification measure, other imaging forms can be considered, Inati said. An abundance of imaging options, she noted, are likely to lead to more definitive diagnosis and allow clinicians to get ahead on issues such as epilepsy type, diagnosis of seizures, antiseizure medication initiation, along with the possibility of drug resistance.

Presurgical evaluation in the next year and beyond may primarily embrace structural and functional imaging, magnetoencephalopathy source imaging and functional mapping, all of which are intended to maximize and predict seizure outcomes.

According to Inati, the benefits of structural MRI in presurgical evaluations are useful when traditional MRI is unable to catch certain focal lesions.

Amplifying these positive effects are 3D imaging, which follows the Harmonized Neuroimaging of Epilepsy Structural Sequences (HARNESS-MRI) protocol, and whose added depth allows for insight into the hippocampal regions and medial structures of the brain.

In addition, Inati continued, 7T MRI offers higher resolution for lesion typing compared with 3T. The higher resolution guards against false positives, and provides better image contrast and higher spatial resolution. According to Inati, 3T imaging improved lesion detection by 18% over 1.5T resolution, while 7T boosts detection by as much as 32% over 3T, with additional processing likely to increase lesion location yield.

Functional imaging may be best applied in cases of negative MRI or data that do not initially align with a concrete diagnosis, but are regional rather than specific and are time based with the peri-ictal seizure period the most beneficial.

“Don’t be afraid of all these imaging things; I think a lot of centers have access to every single technology under the sun,” Inati said. “There have been decades of successful surgeries where you have a structural MRI to go on, so I think these are things to aspire to.”