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 HCC Malignant 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, noninvasive, 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) Multiphasic CT scan Iodinated or non-iodinated contrast 100-150 cc (6%) rate 2-3 cc/sec
Blood supply of the liver Blood supply Portal vein (70%) Hepatic artery (30%) Hepatic vein
Extracellular contrast agent
Non contrast Arterial phase 20-25 sec Portovenous phase 70 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)
Non-contrast Arterial phase Hypervascular tumor Portovenous phase
No contrast Arterial phase Portovenous phase
Arterial phase Portovenous phase THAD
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
Arterial phase Portovenous phase THAD
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
MRI Pro: 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
Benign liver cyst MRI 43219
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 66M RUQ pain, fever with Chill and weight loss Portovenous phase Liver abscess
Solid liver mass FNH Hepatic adenoma HCC Fibrolamellar carcinoma Metastasis Cholangiocarcinoma
Hemangioma 2 months follow up
Hemangioma
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