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Temporal Lobe Lesion, David Yousem, MD (3-26-20)

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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.

2:46

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,

3:31

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,

3:44

number three, coronal FLAIR imaging,

3:46

number four, coronal T1-weighted scans,

3:49

or number five, post gadolinium axial scan. So go ahead and select, and answer,

3:54

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,

4:25

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.

4:36

Thank you poll.

4:41

So,

4:43

what poll sequences do we use for the evaluation of patients with temporal lobe epilepsy?

4:51

There are specific sequences that are recommended for that and that includes

4:56

thin-section coronal T2-weighted scans,

5:00

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,

5:37

look for blood products,

5:39

particularly post-trauma,

5:40

as well as post gadolinium scans to supplement the T1-weighted scans, who knows, maybe in any plane,

5:46

usually using a three-dimensional MPRAGE or a volumetric T1-weighted sequence.

5:56

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?

6:06

Number three, cavernomas? Number four, strokes, or number five, cortical dysplasia? So, once again, we'd like you to answer the poll,

6:15

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,

6:27

or cortical dysplasia for the most common cause of temporal lobe epilepsy.

6:31

So let's see the results.

6:38

Okay, so 59% of people put in mesial temporal sclerosis, and in fact, that is the correct answer,

6:45

and that can be defined in pathology or surgical specimens, as well as clinically.

6:52

So once again, we think about mesial temporal sclerosis,

6:56

this is one of the few cases, where the eye of idiopathic is the most common diagnosis.

Report

Faculty

David M Yousem, MD, MBA

Professor of Radiology, Vice Chairman and Associate Dean

Johns Hopkins University

Tags

Neuroradiology

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