Temporal Lobe Lesion, David Yousem, MD (3-26-20)
HIDEInteractive Transcript
2:04
So, let's get going with the, with the seminar.
2:07
I'll just turn on the light so you can, every once in a while you'll be able to see my face. Okay.
2:13
So today we're going to be talking about imaging of the temporal lobe and temporal lobe lesions,
2:19
and the vast majority of patients with temporal lobe abnormalities will present with epilepsy.
2:26
Now,
2:26
we were going to be talking about temporal lobe epilepsy which occurs in 1% of the world's population.
2:32
About 20-40% of them are refractory to medical management and therefore are considered for surgical treatment.
2:39
So focal onset of seizures will occur in about 60% of these, of these patients.
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So we're going to be talking about evaluation of temporal lobe epilepsy.
2:51
Most of you know I use a mnemonic to keep my mind open to different possibilities in a differential diagnosis. That mnemonic is vitamin C and D.
3:00
And we will be dealing with vascular, infectious, we'll talk a little bit about.. I won't talk very much about trauma,
3:06
but clearly the temporal lobes are susceptible to trauma.
3:10
Metabo- acquired, metabolic, idiopathic neoplastic, congenital and drugs.
3:15
And so these are going to be some of the categories of lesions that we will be describing as part of this seminar.
3:23
Let's start off and see what how we do with doing polling on our Zoom session.
3:28
So you do have that polling function,
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and I'll ask the first question. For the evaluation of patients with temporal lobe epilepsy, what is the most useful pulse sequence? Is it number one,
3:39
axial FLAIR imaging? Number two, coronal T2-weighted scans,
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number three, coronal FLAIR imaging,
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number four, coronal T1-weighted scans,
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or number five, post gadolinium axial scan. So go ahead and select, and answer,
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and then hit the submit button and we will collate the answers from the approximately 600 people that are currently registered for the course.
4:04
So after a little bit of a pause to allow you to think about that, will now look at the results of that polling. So the,
4:14
the highest group is number three for coronal FLAIR Imaging, and that is a very important pulse sequence.
4:24
However,
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I'm going to talk to you about the correct answer which,
4:29
for mesial temporal sclerosis, is going to be coronal T1-weighted scans. So we'll move to the next slide.
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Thank you poll.
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So,
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what poll sequences do we use for the evaluation of patients with temporal lobe epilepsy?
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There are specific sequences that are recommended for that and that includes
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thin-section coronal T2-weighted scans,
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volumetric MPRAGE T1-weighted scans.
5:04
Most people do something along the lines of phase-sensitive inversion recovery in order to reduce... maximize the grey-white differentiational. Although,
5:14
as you can see with the MPRAGE, we're doing pretty well with that.
5:17
And then, as many of you answered the question, coronal FLAIR imaging also is important for looking at the signal intensity, the hippocampus.
5:25
If we're looking at other etiologies for temporal lobe lesions in a patient who may be an adult or for other aspects,
5:33
we will be doing diffusion-weighted imaging, susceptibility weighted imaging,
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look for blood products,
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particularly post-trauma,
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as well as post gadolinium scans to supplement the T1-weighted scans, who knows, maybe in any plane,
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usually using a three-dimensional MPRAGE or a volumetric T1-weighted sequence.
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Okay, so next question is the most common cause of temporal lobe epilepsy is what? Is it, number one, mesial temporal sclerosis? Number two, tumors?
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Number three, cavernomas? Number four, strokes, or number five, cortical dysplasia? So, once again, we'd like you to answer the poll,
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submit your answer and then we will present the group answers in just a moment. So the options are mesial temporal sclerosis, tumor, cavernomas, strokes,
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or cortical dysplasia for the most common cause of temporal lobe epilepsy.
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So let's see the results.
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Okay, so 59% of people put in mesial temporal sclerosis, and in fact, that is the correct answer,
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and that can be defined in pathology or surgical specimens, as well as clinically.
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So once again, we think about mesial temporal sclerosis,
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this is one of the few cases, where the eye of idiopathic is the most common diagnosis.
David M Yousem, MD, MBA
Professor of Radiology, Vice Chairman and Associate Dean
Johns Hopkins University
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