6) Hepatobiliary system

Question 1

Hepatitis (causes, radiological signs: early, late, CT, MRI)

Answer 1

Causes
- Viral infections (A, B, C, E)
- reactions to toxic drugs
Radiological signs
- early signs: aren't visible (blood tests required)
- late signs: cirrhosis or HCC
- CT: shows necrosis, and with C+ it is possible to identify lobulated liver
- MRI: heterogeneous appearance

Question 2

Cholecystitis (cause, MR cholangiopancreatography, cholescintigraphy, gallstone removal)

Answer 2

Causes
- obstruction of cystic duct usually causes gallbladder inflammation

MR Cholangiopancreatography demonstrates the cystic duct and obstructing calculi in the gallbladder neck

Cholescintigraphy has the highest diagnostic accuracy for cholecystitis detection

sometimes stones are pulled through cystic duct into duodenum and left to pass through bowels rather than removing surgically

Question 3

Pancreatitis (causes, CT, MRI)

Answer 3

Causes: excessive alcohol consumption

CT: shows diffuse or focal enlargement, oedema obscures soft tissue

MRI: in acute, extent of necrosis and inflammation shown using dynamic imaging with gadolinium

Question 4

Chronic pancreatitis (causes, plain x-ray, CT, MRI: T1 or T2?)

Answer 4

Causes: results from frequent intermittent injury of the pancreas or alcohol abuse

X-ray: calcifications may be seen on head

CT: ductal dilation, calcification and atrophy. Homogeneous

MRI: T1 better than CT for chronic, heterogeneous

Question 5

Liver cirrhosis (define, causes, imaging signs, CT, MRI)

Answer 5

Define: Chronic destruction of liver cells and structure

Causes: alcohol, post necrotic viral hepatitis, hepatotoxic drugs

imaging signs

• liver surface nodularity
• fat accumulation
• oedema and ascites

CT: normal liver is brighter than spleen, cirrhotic liver is darker than spleen. Portal veins present higher density

MRI: T1 can be used to detect fatty liver

Question 6

Liver hemangioma (Most common___, Non-con CT, arterial phase, T1, T2)

Answer 6

• Most common benign liver tumour

Non-con CT: low attenuation

Arterial phase: Peripheral enhancement of lesion

T1: Hypointense
T2: Hyperintense

Question 7

Hepatocellular carcinoma (most common___, spread, main signs CT)

Answer 7

• Most common abdominal malignancy
• can be a single lesion, multifocal, or completely spread
• CT is preferred modality as C+ helps differentiate
  Main signs
• enlargement of liver w/ heterogeneous “mosaic” pattern of lesion
• necrosis and fat evolution
• HCC becomes hypodense compared to parenchyma in portal venous phase

Question 8

liver metastases (CT, MRI, enhancement)

Answer 8

CT: margin is well defined and less dense than normal parenchyma

MRI

• T1: low SI
• T2: High SI

Rim enhancement that occurs represents tumour peripherally, against a dark necrotic centre

Question 9

Porta hepatis disease (portal triad components, main vascular diseases of P.T., portal vein thrombosis can complicate what and are caused by what)

Answer 9

Portal triad
- main portal vein
- common hepatic artery
- common bile ducts
- lymphatic nerves and connective tissue
Main vascular diseases of P.T
- thrombosis
- stenosis
- aneurysm
Portal vein thrombosis: can complicate liver cirrhosis and HCC. Causes are cirrhosis, pancreatitis, appendicitis, HCC