9) Abdominal Organs

Question 1

Liver imaging key concepts

Answer 1

• Plain radiographs may show liver calcifications, but have limited use in liver imaging
• Nuclear medicine
• CT with IV contrast
• Hepatic angiography

Question 2

Nuclear medicine

Answer 2

• Technetium “hida” scan is performed for functional and morphologic information
• Today has been virtually replaced by ultrasound, CT, and MRI

Question 3

CT with IV contrast

Answer 3

• Imaging method of choice for imaging the liver parenchyma

MRI is valuable in the imaging of primary tumors and liver metastases

Question 4

Hepatic angiography

Answer 4

• Reserved for those patients who need detailed evaluation of the hepatic vasculature

Question 5

Benign tumors

Answer 5

• Hepatic adenoma
• Focal nodular hyperplasia
• More common in young and middle aged women who have been taking birth control pills or hormonal replacement therapy

Question 6

Hepatocellular carcinoma

Answer 6

• Hepatoma

- More common in cirrhotic patients

Question 7

The most common benign liver tumor

Answer 7

• Cavernous hemangioma

Question 8

Hepatic cysts and abscesses key concepts

Answer 8

• These are two nonneoplastic liver masses
• Easily diagnosed with cross-sectional imaging techniques
• Ultrasound for hepatic cyst
• Percutaneous aspiration for liver abscess

Question 9

At ultrasound a hepatic cyst appears

Answer 9

• Sharply defined round mass

- Thin wall that is echolucent

Question 10

Diagnosis of a liver abscess is usually confirmed by

Answer 10

• Percutaneous aspiration

- Performed by a radiologist using CT or ultrasound guidance

Question 11

Blunt liver trauma

Answer 11

• Most commonly caused by MVA’s (motor vehicle accidents) and falls

Question 12

Penetrating liver trauma

Answer 12

• Caused by stab wounds, gunshot wounds, and liver biopsy complications

Question 13

Liver trauma key concepts

Answer 13

• CT with oral and IV contrast is the imaging method of choice for liver trauma
• Unstable patient should be imaged at the bedside with portable ultrasound

Question 14

Cirrhosis, splenomegaly, and ascites key concepts

Answer 14

• Cirrhosis resulting from chronic alcoholism will alter the size, shape, contours, or density of the liver
• CT is the imaging method of choice for cirrhosis, and may show splenomegaly (from portal hypertension), and ascites

Question 15

Splenic trauma key concepts

Answer 15

• The spleen is the organ most frequently injured during blunt abdominal trauma
• CT is the imaging method of choice for splenic trauma
• Unstable patient should be imaged at the bedside with portable ultrasound

Question 16

Gallstones in cholelithiasis

Answer 16

• Appear in ultrasound as echogenic, with acoustic shadows

- Only 10% of gallstones are radiopaque and may be imaged by plain films

Question 17

Imaging method of choice for evaluating gallbladder disease

Answer 17

• Ultrasound

- 95% accuracy rate in the detection of gallstones

Question 18

Acute cholecystitis (or acute inflammation of the gallbladder)

Answer 18

• 90% of cases caused by obstruction of the cystic duct by gallstones

Question 19

Emphysematous cholecystitis can be see radiographically with

Answer 19

• Air in the gallbladder wall

Question 20

Porcelain gallbladder can be seen with

Answer 20

• Calcification of the gallbladder wall

Question 21

Oral cholecystogram (OCG)

Answer 21

• Rarely done today

- Patient ingests a contrast material the night before the exam

Question 22

Cholescinctigraphy key concepts

Answer 22

• Nuclear medicine imaging of the liver and gallbladder
• Also known as the HIDA (hepatobiliary iminodiacetic acid) scan
• Because the cystic duct is nearly always occluded in acute cholecystitis, there is generally no visualization of the gallbladder, even on delayed images

Question 23

Obstruction of the biliary tree imaging options

Answer 23

• Ultrasound
• Cholescintigraphy
• CT
• Percutaneous transhepatic cholangiography (PTC)
• Endoscopic retrograde cholangiopancreatography (ERCP)

Question 24

Percutaneous transhepatic cholangiography key concepts

Answer 24

• Carried out by injection of a water soluble contrast material directly into the liver through the skin
• The biliary tree is seen in great detail, as well as a site of biliary obstruction

Question 25

Pancreas key concepts

Answer 25

- Pancreas is not visible on plain films, but pancreatic calcifications may be evident in some patients (usually diagnostic of chronic pancreatitis) - Ultrasound may show pancreatic masses, peudocysts, and pancreatic duct dilation, but pancreatic anatomy is more clearly delineated with CT

Question 26

Endoscopic Retrograde Cholangiopancreatography (pancreas key concepts)

Answer 26

- Involves cannulization, under fluoroscopic control, of the common bile duct and the pancreatic ducts via the ampulla of Vater during upper endoscopy - When ultrasound or angiographic studies of suspected panceatic disease is uncertain, ERCP is usually conclusive

Question 27

Imaging method of choice for patients suspected of having pancreatic cancer, pancreatitis, pancreatic abscesses, and pancreatic trauma

Answer 27

- CT

Question 28

Courvoisier's law (Courvoisier's sign)

Answer 28

- A statement that the gallbladder is smaller than usual if a gallstone blocks the common bile duct, but is dilated if the common bile duct is blocked by something other than a gallstone, such as pancreatic cancer

Question 29

Renal diseases

Answer 29

- Renal cysts - Polycystic renal disease - Pyelonephritis - Renal masses

Question 30

CT scan of a fractured kidney

Answer 30

- Slice at the level of the kidneys shows no laceration, but reveals blood in the perirenal space, surrounding the kidney

Question 31

Summary

Answer 31

- CT of the GI tract demonstrates conditions that alter the thickness of the bowel wall - CT with contrast is the imaging method of choice for most abdominal organs (with the exception of the gallbladder) - Ultrasound is the imaging method of choice for most gallbladder pathology