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This is Pediatrics week 3 case 5 our diagnosis.

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We're considering is avascular necrosis

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and Bone infarction. We've got

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an MRI here of a Teenage patient and the patient's

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most at risk in the Pediatric population for AVN

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in addition to the congenital and

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idiopathic conditions such as perthy's disease

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and the femur are those patients who have

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some reason for immunosuppression with

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steroids. Chronic steroid. Use is a

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common cause of AVN in the femoral heads humeral

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condiles humeral heads femoral condyles

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and this would be predominantly our

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Leukemia Lymphoma population all of these patients because of bone

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marrow transplants and for other reasons end up with chronic steroid use

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puts them at increased risk. Another population would

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be our Sickle Cell patients who end up

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with obstruction of the capillaries of the bones because of

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those deformed rbcs and then

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of course

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We have all of the osteochondroses which are

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a separate disease process. But by and large are big

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population in the hospital are Leukemia and Lymphoma patients, and

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that's the background of this patient. We're looking at here. Here's some

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T1 Imaging of the pelvis and

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hips the coronal obviously and what

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we're looking for. First of all is abnormal signal

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in the femoral heads and right away. You can see a lot of heterogeneity

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in this left femoral headings to a

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lesser degree some heterogeneity in the right femoral head. We're also

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looking for deformity of the Contour of

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the femoral heading collapse. We don't have a lot of collapse here,

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but we definitely have some irregular signal right at

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the articular surface.

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More on the left but a little bit on the right as well. I'm going

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to go ahead and pull over a fluid sensitive sequence

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and we can see just a little bit of asymmetric effusion on the

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left.

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We can see a little bit of Edema here in the right femoral head

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and to a greater degree in the interrochanteric.

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Region on the left and the femoral head on the left.

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But what's really helpful to look at in these cases

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is the T1 weighted Imaging. I'm going

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to pull up this sequence the axial T1, I think is going to be really valuable

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and right away we can see there's some problems here

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in the femoral heads both on the right but

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even more so on the left

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And one of the ways to think about bone infarction.

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As opposed to some other intraosseous lesion like a tumor

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is the Contour look at the geographic margins

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of this lesion this nice

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dark hypo intense Rim surrounding this

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focal area in the femoral head that is

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very characteristic for a bone infarction. And I think

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it's helpful. If you take a region of interest within a

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bone. Let's say for a given bone you find a circular region

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of Interest.

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The way in which that area of bone might

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have a lesion maybe even a lesion with a circumscribed boundary

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The Contours of that boundary can be

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very helpful. So imagine this is a little silly but imagine you

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put a straw right in the center of the lesion. If you

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blew into that straw the lesion would

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get bigger and almost bulging that's

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what a tumor looks like. But instead

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if you put that straw in the lesion and

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you

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Sucked air out of the lesion it would end

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up looking sort of like this, right? That's what a

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bone infarction looks like. So if you return of course

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to our case, you can see this kind

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of shrunken appearance with this black line the way

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it's kind of a collapsed sphere. That's a bone infarction. We've

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got a smaller one over here and probably a lesser

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one back here several on the left.

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So we have multifocal bone infarctions from

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a vascular necrosis. This is a Leukemia Lymphoma

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patient with chronic steroid use and this

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is not a surprising outcome. It's certainly not

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something we're pleased to have discovered but it's not surprising.

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Here's A sagittal fluid sensitive sequence.

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And you can see the edema and you can see those areas of

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AVN in the femoral heads. I'll go over to the other side even more

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on the left and you can see the

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Deep heterogeneity of the femoral head

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in these circumscribed areas of avascular necrosis.

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That's the end of the case.