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I'm thrilled to bring you an

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abdominal call prep course.

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Scary stories told in the dark.

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As all of you guys progress from

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being radlett to radiologists, I hope

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that these cases can help with that.

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Alright, we're going to start with right upper

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quadrant pain, and we're going to start with

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some of the right upper quadrant anatomy.

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I like to give personality to every organ.

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I always say that the lungs are, you know, very

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fragile tissue paper being exposed to the outside

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world, and the kidneys are hardworking, getting

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tons of blood flow and not asking for much oxygen.

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But I have to tell you, the gallbladder, unfortunately,

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is the stupidest organ in the body, and it is the reason

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why a lot of patients come to the emergency room.

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So we're going to spend a lot of

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time on the right upper quadrant.

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And exploring the different entities that

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can occur to the liver and gallbladder.

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Let's start with simple ultrasound anatomy.

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A big part of medicine is

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actually learning the language.

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Uh, my children always ask

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me, do you know two languages?

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And I say, you know what, I do.

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I'm not bilingual, but I know English and medicine,

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because I know the proper adjectives, the proper

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terminology of so many parts of the body, so much

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of medicine, and communication is really important.

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We always joke at Mass General, there

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are more funerals than retirement parties,

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so we plan to work till we're blind.

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So we need our trainees to have the exact nomenclature

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to specifically tell us what they're seeing on

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the images so that we don't even really have to

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look at them, and we can surmise their diagnoses.

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So on this image, we're going to see

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a sagittal image of the gallbladder.

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This is the gallbladder neck coming

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up into the body and into the fundus.

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You can see that the interior of

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the gallbladder is completely black.

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Coming over here to our proper adjectives

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for ultrasound, we refer to simple black

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as anechoic, meaning no echoes within it.

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That is simple fluid.

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Hypoechoic is slightly decreased in echogenicity

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when compared to the structure you're

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looking at, whether it's the liver or

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kidneys or the like.

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Isoechoic would be the same

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echogenicity as the organ itself.

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Hyperechoic is whiter than expected.

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And reflective is where you have that very bright

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echogenic structure with dense posterior shadowing.

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So back to our ultrasound.

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Ideally, when we look at right upper

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quadrant pain, we would like to image these

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patients after fasting for six to 12 hours.

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Do we have that luxury in the ER?

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Usually not.

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But ideally, you want that

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gallbladder to be quite distended.

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The normal gallbladder size in sagittal dimension

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is about 7 to 10 centimeters, so pretty big,

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actually. It's pretty impressive.

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On the transverse image, it should

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be between three to four centimeters.

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The wall should be very thin, as you can see

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here, um, less than three millimeters in size.

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That's, by convention, the normal

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thickness of the gallbladder wall.

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When we get to the porta hepatis, we

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will look for the common bile duct.

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The common bile duct, by convention, is

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measured at the porta hepatis, just either

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proximal or distal to the hepatic artery.

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Let's go over this, uh, image.

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This is kind of a classic image in ultrasound.

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This is the portal

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vein coming into the liver.

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I know it's red.

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That's just how we do things.

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Um, that shows that the blood is

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coming towards the transducer.

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Over here, you can see that it's red

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coming up towards the transducer.

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You then have the circle that's the hepatic

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artery coming out at you and the common bile duct.

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So again, you either want that measured just

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proximal or distal to the hepatic artery.

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I know people will tell you that that's

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actually the proper hepatic duct.

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That's true, but you know, truth is

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truth, and that's the normal size.

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The common bile duct does increase in

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size as it goes into the pancreatic head.

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So if it's measured too distally, you're going

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to have a larger measurement, um, that may not

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go with the convention that you are referring

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clinicians are used to applying.

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The common bile duct should be

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under six millimeters in size.

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That is very important.

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Now, the surgeons will always tell you

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the six millimeters in size with one

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millimeter per decade above age 60.

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It's never really been revalidated from the

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initial papers where that was written, so I

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usually say it's kind of a unicorn. In general,

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six millimeters is the number we should

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think of as normal. After six millimeters,

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we should be looking for obstruction.

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Now, in a patient who's had a post-cholecystectomy,

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then you have the reservoir effect where your

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bile is now stored in the common bile duct, and

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that duct can be up to 10 millimeters in size.

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Alright. Looking back at the, uh, porta hepatis, again,

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we're always going to look for the portal vein.

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The portal vein should be

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ideally going into your liver.

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Again, we, by convention, will make that red.

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You'll see that the flow is above the

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line here, coming towards the transducer.

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In patients with bad cirrhosis or other

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causes, you can have hepatofugal flow where

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the flow goes from the liver backwards.

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It will be then blue, going against the liver.

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So how I always remember this is hepatopetal is

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pushing towards, and hepatofugal is fleeing from.

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You may remember these terms from high school physics.

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They're similar in their application here.

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Normal liver should be pretty

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homogeneous in echotexture.

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You'll see that the portal veins have a nice echogenic

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border here.

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The bile ducts, should they be dilated,

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would also have an echogenic border.

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Unlike the hepatic veins that

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lack that echogenic border.

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Here are two images of the liver.

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Here's the normal liver.

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The normal liver should have

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similar echotexture as the kidney.

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That's our internal normal.

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This is the shadow from a rib.

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So this would be a normal appearance of the liver as

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opposed to a patient who has fatty liver, where the

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liver is infiltrated with fat, intercellular fat,

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then you have increased echoes throughout the liver,

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uh, and that's very echogenic comparatively to

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the kidney here.

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This can also, um, really absorb your

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sound waves and make it very difficult

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to see distant features within the liver.

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Alright.

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Remember, ultrasound loves water.

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So I always think in my head, Hunt for Red October.

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162 00:05:40,440 --> 00:05:42,299 Do you drive a submarine with a

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big window on the front of it?

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No.

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They use sonar, um, in order to

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steer within the deeps of the water.

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And my goodness, that must be complex.

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So I always like to have that visual in

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my head when I'm thinking of ultrasound.

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These images will show you

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some properties of ultrasound.

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Here we have an image demonstrating that. Normally, as

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our ultrasound beams come through the body,

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there will be attenuation. Attenuation,

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whether it's CT, ultrasound, or whatever,

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is always absorption or scatter.

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So absorbing or scattering our sound waves.

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So normally, there is attenuation through the body.

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The ultrasound processing assumes just a normal 1,540

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meters per second.

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Now, different tissues attenuate

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our sound waves at different rates.

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So up here you can see that's

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water, not a very big attenuator.

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That's why it's so great for, uh, Hunt for Red

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October, as opposed to soft tissue, fat, bone, and air.

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So over here, we have an image of water showing that

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as the sound wave comes through the water, it is not

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attenuated as you would expect, and you have more

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sound waves distal to that simple fluid structure.

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Why does that matter?

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Well, when you have a simple fluid

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structure, you're going to have something

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called increased through-transmission.

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That is where you have very white appearance of

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the tissues deep to a simple fluid structure.

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So in this gallbladder, you're going to see

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that there's anechoic fluid, but deep to that,

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it's very bright, brighter than one would

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expect of that tissue plane because of that

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lack of attenuation of those sound waves.

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As opposed to calcified structures or dense

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structures, which are going to be very reflective,

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and the sound waves will not penetrate,

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resulting in a lack of sound waves distal to

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the, um, structure, and that will

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result in deep, dark shadowing.

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So here we can see beautiful gallstones, very

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echogenic with extreme posterior shadowing.

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When we apply this image to our ultrasound image,

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I think you can have a really nice appreciation of

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anechoic with increased through-transmission, making you

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know it's simple fluid, making you know it's easily

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transmitted as opposed to those reflective gallstones.