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Dr. P here with our pediatric patient under age 10 who

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3 00:00:04,189 --> 00:00:07,950 5 years previously had the diagnosis of neuroblastoma.

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Here's the original CT.

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There's a calcified mass in the right adrenal gland.

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But I want to focus on this lesion right

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here, which is down around this locus

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here, and see if we can spot it on CT.

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Not really.

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Pretty, pretty difficult to, to see on

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CT, but on the axial T2-weighted image.

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There is a spot, a hyperintense spot in the right

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mid-kidney and on the T1 GRE, it's hyperintense.

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So how did we get here?

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Simple cysts should be considered a diagnosis of

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exclusion in children, in true pediatric patients.

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The clinical examination and at least one follow up

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ultrasound examination should be performed to

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assess for the development of any additional cysts

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or any cystic renal syndrome or genetic disorder.

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Also looking for change in cyst size

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or change in imaging characteristics.

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A simple cyst in a child does not

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need contrast-enhanced MR or CT.

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So, how did we get here?

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Because without a risk of malignancy, a standard

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ultrasound with color flow Doppler is absolutely

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sufficient for diagnosis and follow-up, unless

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there's atypicality or a more complex history.

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This is a complex history.

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But also, look at the axial T1 GRE. The lesion is not water.

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It's not dark.

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It is brighter than the surrounding kidney.

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So it's either some type of proteinaceous

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fluid or blood or it could even be fat.

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So what do we do now?

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Well, now we go to dynamic sequencing.

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So let's do that.

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When we go to the dynamic sequencing,

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let's pick something a little bit later.

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We have a whole series of DCE MRI images

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where we keep scanning the kidney again

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and again and again after injection.

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Let's go down the road about 1, 2, 3, 4, 5, 6, about 7,

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7 images into the time activity curve.

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I think we have about 15 or 20 here of images

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of the same kidney at different time points.

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And the lesion is still bright.

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Now, question, is this brightness related to the lesion

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itself just being bright because we have a T1 GRE?

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It was bright on the pre, it's bright on

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the post, or is it actually enhancing?

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Let's go to something rather delayed.

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In fact, very delayed.

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Let's go all the way, almost to the end.

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The lesion's still there.

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Maybe it's a bit brighter.

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And then we've got something that is a

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T1 weighted image with fat suppression.

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And one curious finding is the lesion is hard to see.

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In fact, you hardly see it at all, if at all.

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It might even be right there.

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A little bit darker.

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Darker, similar to the darkness of fat.

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Now, you're still a little bit insecure because you

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have a child with a previous malignancy, and the

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lesion doesn't exactly have, uh, simple round contours.

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If we go back and look at it, it, it has a

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little bit of an exophytic character to it.

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I don't think you can appreciate it on

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this T1 weighted image, but I'll show

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it to you on another, another series.

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But here's what I do in a situation like this.

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I go to the subtraction.

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So you've got to have a subtraction.

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Let's go right,

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right to the area of interest.

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Let me make it the right size.

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Just so you're dialed in here.

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And, uh, let's go to this locus right there.

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There's nothing there.

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So, this lesion was not enhancing at all.

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The signal intensity you were seeing was related

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to the intrinsic character of the lesion.

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It fat suppressed out on the fat

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suppressed delayed T1 weighted image.

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If you look at it very carefully, it

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has a slight exophytic look to it.

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Let's blow it up on the T2 weighted image.

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It's got a slight exophytic character to it.

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This is the cystic component on the inside.

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So while we don't have proof of this case, we may

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be dealing with a very small angiomyolipoma, or AML,

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in the kidney of a child, which would, of course,

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raise the possibility of tuberous sclerosis complex.

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But the bottom line is, it's not a simple cyst.

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Let's move on, shall we? Dr. P out.