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Dr. Schupak,

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let's talk about some pituitary signals.

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And we've got a coronal T2 fast spin echo image on the left,

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a coronal T1 non-contrast image on the right,

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and a sagittal non-contrast image in the middle.

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And many of you are looking with wonder at the

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posterior pituitary segment known as the pars nervosa.

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And it's bright.

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It's got that posterior pituitary bright spot,

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which is present in at least 80% of normal healthy individuals.

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So it means 10%-20%,

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it may be absent at that point or moment in time.

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And that's okay.

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The posterior pituitary gland gets its vascularity

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a little bit earlier than the anterior gland,

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which gets it from the portal plexus.

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And the anterior gland is going to be grayer.

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As you go back,

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things get a little more protonaceous

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in the pars intermedia,

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which is part of the anterior pituitary gland.

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So we got pars distalis, pars tuberalis,

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pars intermedia, which is a little more protonaceous.

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Then we get into a portion,

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a subsegment of the posterior pituitary gland,

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the pars nervosa, which has that bright spot.

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So as we go from the pars distalis right here,

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here's the tuberalis, here's the distalis,

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they're grey.

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Then we start to get into the pars intermedia.

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Maybe it's a little bit brighter there,

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hard to see in the coronal projection.

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And now we hit the pituitary bright spot posteriorly.

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Now, occasionally,

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you're going to see some lower T1 signal

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in the pars intermedia.

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You'll get these little physiologic pituitary microcysts.

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Sometimes, as in this case,

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it'll be a little brighter because there's

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protonaceous material there.

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So there's quite a bit of variability in the normal

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anatomic signal of the pars intermedia, which, again,

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I emphasize is part of the anterior pituitary gland.

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On the T2-weighted image,

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the signal intensity in the pars distalis is

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going to be grey. In the pars intermedia,

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it's going to be variable,

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can be a little hyperintense,

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a little hypointense, or isointense.

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Here it's a little bit hypointense,

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probably due to protonaceous material

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and resultant T2 shortening.

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Now, one other caveat about signal.

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The signal can change in certain states,

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like pregnancy.

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The anterior and posterior lobes become more

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hyperintense and more conspicuous.

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Of course, the gland gets bigger.

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Also, in cirrhotics, the signal intensity may increase.

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And in people on TPN (total parenteral nutrition),

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the signal intensity may rise in both

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the anterior and posterior glands.

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That's a quick hit on the signal intensity of the pituitary.

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Can I make one point?

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Absolutely.

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Dr. Pomeranz talked about the pituitary bright spot as

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a normal finding absent in a certain percentage of people.

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So when is that an important finding?

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Well, if your history says diabetes insipidus,

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that's a very important finding.

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Okay, so the absence of the bright spot

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in that instance would be one of those things

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where the clinician is wondering,

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"Hey, is there a problem with that?

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Sure.

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Or trauma, it can get dislodged out of there.

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With trauma, there's some developmental things.

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And head trauma would be another one.

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Yeah,

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it could be a topic with a growth disturbance

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or precocious puberty.

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So these are all things you have to think about when

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you're missing the posterior pituitary bright spot.

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The only point I did want to make is some individuals

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may not have it at that moment in time.

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Right. Correct.

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Let's move on, shall we?

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Correct.