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Let's talk now about benign prostatic

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hypertrophy on MRI, which can be subdivided

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into individual types based on the

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lobes or segments that are enlarged.

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And that'll be a separate vignette.

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Let's define BPH.

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It is defined as a gland that is

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25 cubic centimeters or greater.

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For smaller glands, we may use

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one technique to measure it.

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For larger glands, another technique.

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Let's summarize those techniques.

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So I've got three.

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Three-dimensional T2 Fast Spin Echo MRI images.

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Here's an axial.

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Here's the reconstructed sagittal.

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And here's the reconstructed

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coronal off the 3D axial.

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So this was the original plane of acquisition.

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I'm going to, at the mid-gland level, take

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the transverse dimension of the gland.

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Let's mark it here.

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The anteroposterior dimension of the gland

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at its widest portion, let's mark it here.

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And the cranial caudate dimension of

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the gland off the coronal projection,

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which we'll mark right there.

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The gland kind of comes in like this,

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makes a little curve, and then goes down.

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So we've got width, we've got AP

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dimension, and we've got length.

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So let's do the two types of calculations.

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For glands that are a little bit bigger, how big?

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Well, pretty big.

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So that's more subjective.

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A lot of people like to use length

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times width times height, which we have

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just measured for you, times pi over 6.

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So that is known as the ellipsoid volume.

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For glands that are a bit smaller, but

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still enlarged, some people like to

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use what's known as the bullet volume.

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I'll call it B.

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And that is basically the same thing.

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Length times width times

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height times 5 pi over 24.

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You can actually measure on MRI the

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overall gland volume and come up with a

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severity of BPH based on absolute volume.

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So glands that are say 55 to 75, pretty enlarged.

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75 to 90, very enlarged.

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Over 90, massively enlarged.

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And again, a normal is 25

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cubic centimeters and below.

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The two measuring techniques, the ellipsoid

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technique and the bullet technique.

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This one for smaller glands,

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this one for larger glands.

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Benign prostatic hypertrophy.