Ultrasound of Gallbladder

Ultrasonic anatomy Located inferior to rt. Lobe of liver

Long axis 6-12 cm , short axis 3-5 cm (4*10cm usually at fasting )

Contracted < 5 cm

Distended > 12 cm when the patient is fasting

Max normal diameter of CBD=4 to 7 mm

Wall Thickness:

Measured in the side in contact with the liver.usually < 3 mm.

From 3-5 mm >>> suspect thick wall

More than 5 mm >>> It is a thick wall gall bladder which is seen in:

Cholecystitis (acute-chronic).

Hepatitis ( viral).

Common Bile Duct is anterior to portal vein.this is the position of porta hapatis

Imaging technique

-overnight fast(6-12hr) to distent GB and remove gas shadow

Short focal length transducer is better as GB is anteriorly located organ.

Supine ,LPO position for imaging

Ganarally dilated bile duct seen in longitudional scan.portal vein ant. To IVC

Contents

Stones:

seen inside, mobile except at the neck they appear white with posterior shadow.

Thick bile.

Called sludge.Change with changing position. The picture occurs in the presence of thick bile in patients on IV fluids for 3-4 days and in inflammation.

Parasite:

Fasciola appears pearl shape.

Move as a whole.

Cancer & polyps:

Polypoidal or heterogeneous mass.

Pathologies

CHOLELITHIASIS-gall stone have high reflictive echo with prominent acoustic posterior shadow

Gravity dependent movement confirms diagnosis

Wall thickening as a hypoechoeic region b/n two echoeic lines,suggest chr.cholecystitis,alcoholism.

Sludge

No acoustic shadow

Low to mild level echoes

Moves very sluggishly

Acute cholecystitis

Associated with cholelithiasis in most cases

Gall stone with focal GB tenderness,usg MURPHY s sign

Pericholecystic edema

Wall edema or wall hypoechoeic

Sometime stone may not be present ,called acalculus cholecystitis eg.burns,old age,after major trauma,and fasting patient

Intrahepatic bile duct

If bile duct are >2mm dia

Second ultrasonic feature of bile duct dilatation is irregularity of bile duct dilatation

Extrahapatic bile duct

Normally 4mm at age 40,5mm at 50

Common site at head of pancrease when double duct sign may be seen

Cbd seen by parasagittal scan

Other facts

Fluid filled colon may appear like GB,wait and watch peristalsis.

In bed ridden ,numerous mass,sludge is not pathological

Polyps donot produce posterior shadow

In obese,difficult to see GB from subcostal approach