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Hello and welcome to Noon Conference hosted by MRI Online. In response to

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the changes happening around the world right now and the shutting down of

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in person events, we have decided to provide free Noon Conferences to all

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radiologists worldwide. Today, we are joined by Dr. Grace Mitchell. Dr.

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Mitchell is a pediatric radiologist and reads most studies within this specialty.

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She has a particular interest in fetal MRI in trainee education.

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A reminder that there will be a Q&A session at the end of

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this lecture, so please use the Q&A feature to ask your questions and

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we will get to as many as we can before our time is

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up. Just one housekeeping item, we will be using the polling system today.

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So just so you know if the poll is maybe obstructing your view

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at all, you can move the window around your screen.

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That being said, thank you all for joining us today. Dr.

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Mitchell, I'll let you take it from here. All right, and you should

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be seeing my title slide. I am a pediatric radiologist in Kansas City,

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Missouri and so I do 100% PEDs. And so today we're going to be

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talking about the Don't Touch Skeletal Lesions within the pediatric world.

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I had no disclosures. Our main objectives today are to review imaging findings

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of pediatric don't touch lesions in the bone, and also to consider other

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differentials and other imaging findings of lesions and similar appearing,

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but different lesions. So what kind of things can we see?

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Well, of course, we can see normal variants, particularly in kids,

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there's a lot of different shades of normal. We can see traumatic and

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post traumatic sequela, we can see vascular abnormalities and we can see

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different types of neoplasms including benign neoplasms that we wouldn't

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touch. So we're going to get started right away with a case.

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So we'll pull up case number one and you should see the polling

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question shortly. This is a radiograph of the pelvis

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obtained because the patient had pelvic pain. What is the likely diagnosis?

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I'll give you a little clue. I'm going to draw your attention

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to where the arrows are pointing. Are these normal? Are these infectious?

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Are these traumatic? Are these tumors? Alright, great job. So the vast majority

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of you answered that these are normal, and they are in fact

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normal. What are they? These are called ischiopubic synchondrosis. So these

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are obviously seen in kids who still have open physis. You can see

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throughout the pelvis and proximal femurs that their physis are open.

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So here we have what are called synchondrosis. In this particular image,

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which is different than the one I just showed you, I'm showing you

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asymmetric ossification. So these synchondrosis in very young children will

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have a wide open lucency, but as they start to ossify they can

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have a variety of appearances, including the one shown in the case where

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they were symmetrically ossifying with a boldest appearance, kind of like

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on the right on this patient, but they can also be asymmetric.

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And that can be quite confusing. So in this particular kid,

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you can see the ossification process is a little bit faster on the

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left where it looks more normal and adult like where it's fused,

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but here it's not. And in the absence of focal symptoms or pain,

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that is simply normal. These joints close before puberty, they're made of

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hyaline cartilage and they are most typically asymptomatic.

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And hence we would not want to do anything with them and they're classified

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as a don't touch lesion. Be aware that in this same area you

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can have something called Van Neck Odelberg disease.

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So in this case we see a patient who has an axial T2

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fat sat MRI, and we can see the arrow pointing to a similar

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synchondrosis, but there is marrow edema and a little bit of soft tissue

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edema around it. So you can in fact get

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pain and edema from the closing process and some hyperostosis. You can also

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get it with excessive hamstring tendon pulling. And so even if you have

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a patient with pain, most of the time, if this is the only

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finding the marrow edema at most if you happen to get MRI,

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you would observe and treat expectantly and let it rest.

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This is in distinction to the next case that I'm going to show

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you. This is a patient who has a T2 fat sat axial image

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through the same region, as well as a T1 post contrast fat sat. And

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we can see here there's something different going on. On the right side

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we see a normal looking incompletely fused synchondrosis. On the left side

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we can see that there is fluid within that space, there's also edema around

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it in the marrow but then more worrisome we see fluid outside of

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that space, and a lot of soft tissue edema and the surrounding musculature.

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We see that that fluid does not enhance but the surrounding inflammation

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does. And so, this is a case of a patient who actually had

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osteomyelitis of that region. And this can happen because the bone on either

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side of the synchondrosis are metaphyseal equivalents. And so,

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such there is an arterial circulation with some sluggish veins, and so can

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be at risk of osteomyelitis if there's some bacteria that are floating around

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and decide to set up shop there. So, be aware there is

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most typically we see normal synchondrosis but if there are other symptoms,

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specifically pain or certainly fever or anything that would make you think

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of osteomyelitis, that would warrant further investigation. Great job.

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We'll move on to the next one. Another case.

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Where is the area of acute abnormality? So, you see a lateral radiograph

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of the knee, Is there no abnormality? Is there something going on in

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the anterior or posterior femur? Something going on in the anterior, posterior

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tibia? Alright so we have a range of answers.

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Few people answered all of them, actually, which is great. The majority

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thought that the anterior tibia looked abnormal. So we'll come back to that.

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So what I was actually wanting for you, actually, to pay attention to

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the most was this area here, the posterior femur, but this in fact

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is normal. There is no area of acute abnormality, it's a little bit

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of a trick question, but I agree that that's something sticks out about,

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so it looks a bit irregular, a little bit pinched out.

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So what could this be? But we'll get to that in a moment.

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I do want to address the anterior tibia.

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I think this is an area that frequently can be confusing even to

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a pediatric radiologist because we have the hypothesis of the anterior tibial

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tubercle, and it can have a wide variety of appearances as it's also fine.

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Remember that there is an apophysis that can be

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separate from the parent bone for a while as it ossifies, you can

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sometimes see fragmentation with multiple fragments there that are not all

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connected yet just depending on the timing. Generally, though, the fragments

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should look rounded and well...