Imaging of liver and pancreas

. .

•

•

•

Disease of the liver

• Focal liver disease

• Diffusion liver disease

Focal liver disease

Benign

• Cyst

• Abscess

• Hemangioma

• FNH

• Hepatic adenoma

Malignant

• HCC

• Fibrolamellar

carcinoma

• Metastasis

• Cholangiocarcinoma

Diffuse liver disease

• Cirrhosis

• Metabolic disease

– Hemochromatosis

– Wilson’s disease

– Fatty liver

Anatomy of liver

Hemodynamic

• Blood supply

– Portal vein (70%)

– Hepatic artery (30%)

– Hepatic vein

Anatomy of the liver

• Morphological anatomy – 3 lobes

– Right lobe

– Left lobe

– Caudate lobe

• Functional anatomy – 8 segments

– Base on portal and hepatic vein supply

Morphological anatomy

Division between:

• Right lobe and left lobe: Middle hepatic

vein

• Left lobe and caudate lobe: Ligamentum venosum

Caudate lobe

Morphological anatomy

Imaging modality

• Plain film: not useful

• Ultrasound: good screening test, non-

invasive, cheap

• CT: good modality

• MRI: the best at present

Plain film

Ultrasound

Pro:

• Non-invasive method

• Good screening tool

• Not expensive

• Widely available

Con:

• Operator dependent

• Less specificity than CT and MRI

Hemangioma

CT

Pro:

• Good for lesion detection and characterization

• Widely available in most hospital

Con:

• Radiation hazard

• Risk of contrast allergy

• Risk in patient with renal insufficiency

Contrast enhanced CT

• Arterial phase (25-30 sec)

• Portovenous phase (70 sec)

• Delay phase (10-20 min)

• Iodinated or non-iodinated contrast 100-150 cc (6%) rate 2-3 cc/sec

“Multiphasic CT scan”

Blood supply of the liver

• Blood supply

– Portal vein (70%)

– Hepatic artery (30%)

– Hepatic vein

Extracellular contrast agent

Non contrast Arterial phase20-25 sec

Portovenous phase70 sec

Arterial phase

• Scan at 25-30 sec. after injection

• Clearly seen hepatic artery

• Minimal hepatic parenchymal enhancement

Benefit:

• Good for hypervascular tumor detection

• Transient hepatic attenuation difference (THAD)

Arterial phase Portovenous phase

Non-contrast

Hypervascular tumor

No contrast

Arterial phase Portovenous phase

THAD

Arterial phase Portovenous phase

Portovenous phase

• Scan at 70 sec after injection

• Clearly seen hepatic vein and portal vein

• Enhancement of hepatic parenchyma

Benefit: Good for

• Hypovascular tumor

• Biliary tract dilatation

• Hepatic injury

Non contrast

Arterial phase Portovenous phase

THAD

Arterial phase Portovenous phase

Biliary tract dilatation

Portovenous phase

Pitfall:

• 35% miss HCC

• 14% miss hypervascular metastasis (breast,

melanoma, choriocarcinoma, pancreatic islet cell tumor, GIST, etc)

Delay scan (equilibrium phase)

• Scan at 10-20 min after injection

Benefit:

For confirmation of

• Hemangioma

• Intrahepatic cholangiocarcinoma

MRIPro:

• Good for lesion detection and characterization (better than CT)

• No radiation hazard

• No risk for contrast allergy and in patient with renal insufficiency

Con:

• Expensive

• Not widely available

• Cannot perform in patient with metal in body

Liver cyst

Ultrasound

• Anechoic

• Thin wall

• Posterior acoustic enhancement

CT

• Thin wall

• Clear water content

MRI 43219

Benign liver cyst

US, CT: Sharp margin, no internal septation

Clear internal fluid

Liver abscess

Ultrasound

• Irregular wall

• Echogenic content

• May have acoustic enhancement

CT

• Hypodensity collection with irregular peripheral enhancement

Unliquified abscess Liquified abscess

Liver abscess

Non-contrast Arterial phase

Portovenous phase

66M RUQ pain, fever withChill and weight loss

Liver abscess

Solid liver mass

• FNH

• Hepatic adenoma

• HCC

• Fibrolamellar carcinoma

• Metastasis

• Cholangiocarcinoma

Hemangioma

2 months follow up

Hemangioma

http://smiswi.sasktelwebhosting.com/Images/US abd multiple liver masses.jpg

Pancreatic mass

Pancreatic mass

• CT is investigation of choice

• CT with dual phase and thin section at pancreas

Staging

• Local invasion: adjacent structure and vascular

• Adenopathy

• Metastasis

Investigation of jaundice

Etiology

1. Hemolysis

2. Bilirubin conjugation problem

3. Obstruction of biliary tract

Etiology

1. Hemolysis

• Overproduction of heme

• High indirect bilirubin

• Thalassemia

Etiology

2. Bilirubin conjugation problem

• Hepatitis (viral, bacterial)

• Sepsis

• Liver failure

• Diffuse liver disease

Etiology

3. Biliary tract obstruction

• Stone

• Stricture

• Tumor: cholangiocarcinoma and

pancreatic carcinoma

• Choledochol cyst

Investigation of jaundice

• US is investigation of choice

Follow by

• CT, ERCP, PTC

• Or MRCP

Ultrasound

- NPO 4-6 hrs

- Biliary tract dilatation

- CBD dilatation- Liver disease

CT

Indication

• Further investigation of site and cause of

jaundice.

• Preparation: oral and IV contrast

• NPO 4-6 hrs

• Good in obesity patient

ERCP

ERCP

Indication

• Inconclusive ultrasound finding

Patient preparation

• NPO 4-6 hrs

• Mild sedation

• Prophylatic antibiotic

ERCP

Post procedure care

• Post sedation care

• Look for infection and pancreatitis

Complication

• Acute pancreatitis

Percutaneous transhepatic

Cholangiography (PTC)

PTC

Indication

• High level of biliary obstruction

• Fail ERCP

• Stent placement

Contraindication

• Bleeding disorder

• Biliary tract infection

PTC

Patient preparation

• Clotting study

• Prophylactic antibiotic

• NPO 4-6 hrs

• Sedation

PTC

Post procedure care

• Observe bleeding and infection

Complication

• Hemorrhage

• Septicemia

• Bile leak, bile peritonitis

T-tube cholangiography

Post cholecystectomy

with T-tube placement

MRCP

Indication

Preoperative

• find cause of obstruction

• fail ERCP

Postperative

• Recurrent jaundice

• symptom of pancreatitis

Portal hypertension

Portal hypertension

• Increase portal venous pressure

• Cause: Intrahepatic, extrahepatic

• Intrahepatic: cirrhosis

• Extraheaptic: hepatic vein obstruction

• Physiology: splenomegaly, collateral

circulation

Imaging of portal hypertension

Indication

• Prove portal hypertension

• Find cause

• Find complication: collateral circulation,

splenomegaly

CT

• Same indication and finding as ultrasound

Liver cirrhosis: enlarged caudate and left lobe liver