Neuroimaging in Epilepsy With Dr. Christopher Skidmore

Neuroimaging is a tool to classify and ascertain the etiology of epilepsy in people with first or recurrent unprovoked seizures. In addition, imaging may help predict the response to treatment. To maximize diagnostic power, it is essential to order the correct imaging sequences.

In this episode, Aaron Berkowitz, MD, PhD, FAAN speaks with Christopher T. Skidmore, MD, author of the article “Neuroimaging in Epilepsy,” in the Continuum February 2025 Epilepsy issue.

Dr. Berkowitz is a Continuum® Audio interviewer and professor of clinical neurology at the University of California, San Francisco

Dr. Skidmore is  an associate professor of neurology and vice-chair for clinical affairs at Thomas Jefferson University, Department of Neurology in Philadelphia, Pennsylvania.

Additional Resources

Read the article: Neuroimaging in Epilepsy

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Host: @AaronLBerkowitz

Guest: @ctskidmore

 Full episode transcript available here

Dr Jones: This is Dr Lyell Jones, Editor-in-Chief of Continuum, the premier topic-based neurology clinical review and CME journal from the American Academy of Neurology. Thank you for joining us on Continuum Audio, which features conversations with Continuum's guest editors and authors who are the leading experts in their fields. Subscribers to the Continuum journal can read the full article or listen to verbatim recordings of the article and have access to exclusive interviews not featured on the podcast. Please visit the link in the episode notes for more information on the article, subscribing to the journal, and how to get CME.

Dr Berkowitz: This is Dr Aaron Berkowitz, and today I'm interviewing Dr Christopher Skidmore about his article on neuroimaging in epilepsy, which appears in the February 2025 Continuum issue on epilepsy. Welcome to the podcast, Dr Skidmore. Would you please introduce yourself to our audience? 

Dr Skidmore: Thank you for having me today. I'm happy to talk to you, Dr Berkowitz. My name is Christopher Skidmore. I'm an associate professor of neurology at Thomas Jefferson University in Philadelphia. I'm a member of the Jefferson Comprehensive Epilepsy Center and also serve as the vice chair of clinical affairs for the department. 

Dr Berkowitz: Thank you very much for joining us and for this fantastic article. It's very comprehensive, detailed, a very helpful review of the various types of brain pathology that can lead to epilepsy with very helpful images and descriptions of some of the more common findings like mesial temporal sclerosis and some of the less common ones such as cortical malformations, heterotopia, ganglioglioma, DNET. So, I encourage all of our listeners to read your article and take a close look at those images. So, hopefully you can recognize some of these findings on patients’ neuroimaging studies, or if you're studying for the right or the boards, you can recognize some of these less common congenital malformations that can present in childhood or adulthood with epilepsy.

In our interview today, what I'd like to do is focus on some practical tips to approaching, ordering, and reviewing different neuroimaging studies in patients with epilepsy. So to start, what's your approach when you're reviewing an MRI for a patient with a first seizure or epilepsy? What sequence do you begin with and why, how do you proceed through the different sequences and planes? What exactly are you looking for? 

Dr Skidmore: It's an important question. And I think to even take a step back, I think it's really important, when we're ordering the MRI, we really need to be specific and make sure that we're mentioning the words seizures and epilepsy because many radiology centers and many medical centers have different imaging protocols for seizure and epilepsy patients as compared to, like, a stroke patient or a brain tumor patient. I think first off, we really need to make sure that's in the order, so that way the radiologist can properly protocol it. Once I get an image, though, I treat an MRI just like I would a CAT scan approach with any patient, which is to always approach it in the same fashion. So, top down, if I'm looking at an axial image. If I'm looking at a coronal image, I might start at the front of the head and go to the back of the head. And I think taking that very organized approach and looking at the whole brain in total first and looking across the flare image, a T2-weighted image and a T1-weighted image in those different planes, I think it's important to look for as many lesions as you can find. And then using your clinical history. I mean, that's the value of being a neurologist, is that we have the clinical history, we have the neurological exam, we have the history of the seizure semiology that can might tell us, hey, this might be a temporal lobe seizure or hey, I'm thinking about a frontal lobe abnormality. And then that's the advantage that we often have over the radiologist that we can then take that history, that exam, and apply it to the imaging study that we're looking at and then really focus in on those areas. But I think it's important, and as I've illustrated in a few of the cases in the chapter, is that don't just focus on that one spot. You really still need to look at the whole brain to see if there's any other abnormalities as well.

Dr Berkowitz: Great, that's a very helpful approach. Lots of pearls there for how to look at the imaging in different planes with different sequences, comparing different structures to each other. Correspondent reminder, listeners, to look at your paper. That's certainly a case where a picture is worth a thousand words, isn't it, where we can describe these. But looking at some of the examples in your paper, I think, will be very helpful as well. So, you mentioned mentioning to the neuroradiologist that we're looking for a cause of seizures or epilepsy and epilepsy protocols or MRI. What is sort of the nature of those protocols if there's not a quote unquote “ready-made” one at someone 's center in their practice or in their local MRI center? What types of things can be communicated to the radiologist as far as particular sequences or types of images that are helpful in this scenario?

Dr Skidmore: I spent a fair amount of time in the article going over the specific MRI protocol that was designed by the International League Against Epilepsy. But what I look for in an epilepsy protocol is a high-resolution T2 coronal, a T2 flare weighted image that really traverses the entire temporal lobe from the temporal tip all the way back to the most posterior aspects of the temporal lobe, kind of extending into the occipital lobe a little bit. I also want to see a high resolution. In our center, it's usually a T1 coronal image that images the entire brain with a very, very thin slice, and usually around two millimeters with no gaps. As many of our neurology colleagues are aware, when you get a standard MRI of the brain for a stroke or a brain tumor, you're going to have a relatively thick slice, anywhere from five to eight millimeters, and you're actually typically going to have a gap that's about comparable, five to eight millimeters. That works well for large lesions, strokes, and big brain tumors, but for some of the tiny lesions that we're talking about that can cause intractable epilepsy, you can have a focal cortical dysplasia that's literally eight- under eight millimeters in size. And so, making sure you have that nice T1-weighted image, very thin slices with no gaps, I think is critical to make sure we don't miss these more subtle abnormalities.

Dr Berkowitz: Some of the entities you describe in your paper may be subtle and more familiar to pediatric neurologists or specialized pediatric neuroradiologists. It may be more challenging for adult neurologists and adult neuradiologists to recognize, such as some of the various congenital brain malformations that you mentioned. What's your approach to looking for these? Which sequences do you focus on, which planes? How do you use the patient 's clinical history and EEG findings to guide your review of the imaging?

Dr Skidmore: It's very important, and the reason we're always looking for a lesion---especially in patients that we're thinking about epilepsy surgery---is because we know if there is a lesion, it increases the likelihood that epilepsy surgery is going to be successful. The approach is basically, as I mentioned a little bit before, is take all the information you have available to you. Is the seizure semiology, is it a hyper motor semiology or hyperkinetic semiology suggestive of frontal lobe epilepsy? Or is it a classic abdominal rising aura with automatisms, whether they be manual or oral automatisms,