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In this vignette, I want to focus on two major points.

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One, the role of fat suppression in T1 imaging, and

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two, T1 spin echo,

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standard resolution, five millimeters with a one-millimeter skip,

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fat suppression, contrast-enhanced imaging, so delayed

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contrast imaging. So here's the pre-contrast

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fat suppression. Here's the post-contrast fat suppression.

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These were done non-dynamically, five-millimeter cut,

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one-millimeter skip, and as a comparison, as a reference on the

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left, is the T1 standard spin echo

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without fat sat. So let's talk about fat sat.

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Fat-saturated T1-weighted images help distinguish between

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hemorrhage and fat, as in a mature

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cystic teratoma.

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Now, in general, low viscosity mucin has low

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T1 signal and high T2 signal.

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High viscosity mucin might have higher T1 signal, something

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like this, even though this isn't a mucinous tumor, but it is a

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proteinaceous hemorrhagic cyst.

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So high viscosity mucin, bright on T1, low

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viscosity mucin, low on T1. Now, what if it was

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a cystic teratoma that contained fat?

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It'd be bright on the T1 without fat suppression. Fat is white.

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No fat sat. And then when we fat suppress, if it was a mature cystic

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teratoma, it would get darker.

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It's not.

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Therefore, this has to be some type of proteinaceous material,

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blood, or mucin, and you've essentially

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excluded a mature cystic teratoma.

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Let's talk about some other lesions that occur in the ovary,

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especially as they relate to the appearance on T1.

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One is a fibrotic lesion. Fibrosis or smooth muscle has

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low or intermediate signal intensity on T1 and low

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signal on T2, compared with other soft tissues because of the

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T2 shortening effects of intramuscular actin,

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myosin, collagen, and the decreased extracellular

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fluid compared with surrounding tissues.

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We don't have a fibrous lesion here, but some examples would be fibroma,

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fibrothycoma, cystadenofibroma, Brenner tumor,

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and the walls of certain chronic pelvic abscesses.

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Masses that contain smooth muscle include leiomyoma and the

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stroma of adenomyosis. Back to the contrast.

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This is a standard T1, three to four minutes, fat suppressed,

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pre-contrast. Here's the post-contrast.

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Doesn't have quite the spatial resolution, the small field of view,

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and the thin section imaging that might allow you to see papillary

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projections inside this hemorrhagic cyst

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with a thick wall.

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We do see enhancement of the uterus, enhancement of the veins on

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either side, normal enhancement of the thin

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homogeneous walls of simple cysts, and then the

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thick-walled area that has a little bit of lumpy bumpy appearance right there, I'm

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going to blow it up, that requires further scrutiny, which we

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did do on a prior dynamic vignette that is paired

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with this one.

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One other caveat.

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You can subtract even your 2D

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simple T1 spin echo imaging, the pre from the post.

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If you have a papillary projection, let's look at a round mass like

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an ovarian cyst. It's got a papillary projection, but that

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papillary projection is cold. Doesn't enhance.

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You don't see it on subtraction, it's probably debris.

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It's probably either debris or blood.

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Whereas if it enhances with contrast after you inject it,

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then the odds are it's a neoplasm, either benign or malignant, and

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requires further investigation.