Dr. P here talking T2 weighted imaging assessment in the transitional zone, score two. Now I want to emphasize again that this score two is not the PI-RAD score. These individual scores for say DWI or T2, or some of the other assessments get added together to produce the actual PI-RAD score. So this is a score within a score, and we are comparing how you score the TZ for T2, PI-RAD 2.0 versus PI-RAD 2.1.
So let me start by making a prostate. I'll use my drawing tool and make a nice big circular prostate and my prostate doesn't have a peripheral zone because I'm not concerned with that right now. I'm just worried about the TZ and I'm going to make the TZ a pretty homogeneous structure to start with. And then I'm going to produce a nodule inside. Now in PI-RADS 2.0, there is a circumscribed nodule that's hypointense or heterogeneous that's encapsulated.
So let's make our nodule homogeneous first. That's a homogeneous nodule. And then let's make a heterogeneous nodule. So here's a heterogeneous nodule and it may have some other sort of signals inside it, that's okay. So heterogeneous nodule, homogeneous nodule, and our nodules are encapsulated. So we're going to see a nice dark rim around the outside and we'll make our rim nice and black. So this one's encapsulated all the way around and this one's encapsulated all the way around. And that was your score two, in the transitional zone as it relates to T2 signal, and PI-RADS 2.0.
Now let's turn our attention to PI-RADS 2.1. Very similar to PI-RADS 2.0. We're going to have a nodule, but this time our nodule can be homogeneous or heterogeneous as long as it's mostly encapsulated, so it doesn't have to be completely encapsulated. So we're going to have a capsule that looks like that. And internally it can be nice and smooth in terms of its signal homogeneous, or it can have some mixed character to it inside, as long as it's mostly encapsulated, or if it's completely homogeneous. In other words, if it's all the same shade, here we go again with our nodule. So it's very smooth internally, but it can be unencapsulated.
Now there's one other caveat. There can be some signal in between these nodules. So we're going to make that signal say here. You can see it's a little different than the nodule itself. It's a little different than the background signal of the transitional zone, and this occurs frequently between nodules. As long as this doesn't have mass effect, it doesn't have any of the other criteria that we're discussing in other sections, it's fine. So we're going to have signal between nodules. We're going to have nodules that are partially encapsulated, homogeneous, or heterogeneous. We're going to have nodules that are unencapsulated as long as they are homogeneous. So there is a subtle distinction between score two TZ for T2, PI-RADS 2.0 and PI-RADS 2.1.
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Content reviewed: December 29, 2021