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This is a nice case which illustrates the importance of getting plain

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radiographs to accompany any cross-sectional study, particularly MRI.

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In the middle, we have axial fat-suppressed fluid-sensitive sequence,

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and on the right, we have a coronal fat-suppressed

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fluid-sensitive sequence.

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And right away, we noticed an area of bright signal abnormality.

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It's very heterogeneous.

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It has areas of what looks like fluid, what looks like septations, and what looks like

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maybe some calcification or blood, or mineralization at the periphery.

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It's very ugly looking, if you will.

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And what muscle does it involve?

0:45

It looks like it involves the vastus intermedius.

0:50

Lateralis over here and we have got the medialis over here.

0:53

So it looks like it's involving the vastus intermedius, mainly.

0:57

In coronal image, it doesn't do anything to relieve us of what this may be.

1:03

So there's a broad differential.

1:05

It could be trauma, it could be tumor, it could be inflammatory process.

1:11

So this is where the plain radiograph really comes into view, because the plain

1:15

radiograph is going to reveal what you see here on this image.

1:20

This pattern of calcification.

1:22

Okay, this pattern of calcification, very peripheral.

1:26

It looks like it sort of follows the fibers of the muscle.

1:31

You see it over here. You see it on this side.

1:33

There really isn't any bone destruction.

1:35

There's no periosteal reaction.

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And as we dive a little deeper

1:40

into the history, the patient did have a direct blow to this area.

1:44

So this is very consistent with myositis ossificans

1:48

or dystrophic calcification from trauma.

1:51

Had we got this plain radiograph and it showed very chunky calcifications,

1:55

periosteal reaction, soft tissue component,

1:58

then our differential would have been completely different.

2:01

We would have been leading down the path of a malignancy.

2:05

But because of these wispy

2:07

patterns of calcification sort of conforming to the

2:12

the pennate of the muscles, we can be confident that we're looking

2:16

at just a simple hematoma with dystrophic calcification.

2:20

Myositis ossificans.