[07.21] Hepatobiliary System Imaging V2.1.pdf

Assess liver, gallbladder, and bile ducts for structural and functional abnormalities

What is the primary purpose of hepatobiliary imaging?

Midclavicular line along the vertical (craniocaudal) axis

Along which anatomical line and axis is liver size measured in imaging?

Normal

A liver measurement of less than 13 cm along the midclavicular line indicates what?

Indeterminate

A liver measurement between 13 cm and 15 cm is classified as what?

Hepatomegaly

A liver measurement greater than 15 cm indicates what condition?

25%

What percentage of the liver's blood supply comes from the hepatic artery?

75%

What percentage of the liver's blood supply comes from the portal vein?

Couinaud classification

What is the name of the system used to divide the liver into 8 functional segments?

Left lobe

Segments I, II, III, IVa, and IVb belong to which lobe of the liver?

Right lobe

Segments V, VI, VII, and VIII belong to which lobe of the liver?

Segment I

Which Couinaud segment corresponds to the caudate lobe?

Knowledge of segments is beneficial for surgical procedures

What is the primary clinical benefit of understanding Couinaud segmental anatomy?

Stores and concentrates bile

What is the physiological function of the gallbladder?

Interlobar fissure

What is the key landmark used to identify the gallbladder on an ultrasound?

10 cm x 4 cm

What are the maximum normal dimensions for a distended gallbladder?

Less than 3 mm

What is the normal thickness of the gallbladder wall?

Reaction to external pathology or intraluminal pathology

A gallbladder wall greater than 3 mm may indicate what?

Intrahepatic ducts

Which ducts are located entirely within the liver?

Common hepatic duct (CHD)

Which duct is located closer to the liver than the common bile duct?

Converged intrahepatic ducts join the cystic duct

How is the common bile duct (CBD) formed?

$\le$ 6 mm

What is the normal diameter of the common bile duct in a healthy adult?

Increases proportional to age

What happens to the normal diameter of the CBD as a patient grows old?

7 mm

What is the normal CBD diameter for a 70-year-old patient?

Ampulla of Vater

The common bile duct joins the main pancreatic duct to enter what structure?

1.8 mm to 2.0 mm

What is the normal diameter range for intrahepatic ducts?

Anterior pararenal space

In which specific anatomical space is the pancreas located?

Pancreatic head

Which part of the pancreas is closely associated with the distal common bile duct?

Distal CBD or Ampulla of Vater

Obstructions or masses in the pancreatic head typically obstruct which two structures?

3 cm

What is the maximum normal diameter of the pancreatic head?

2.5 cm

What is the maximum normal diameter of the pancreatic body?

2 cm

What is the maximum normal diameter of the pancreatic tail?

Progressively decreases

What happens to the size of the pancreas as a person ages?

Detecting calcifications, air, or organ enlargement

What is the primary limited role of plain radiography (X-ray) in hepatobiliary imaging?

Displacement of bowel loops

What is an indirect sign of hepatomegaly on a plain X-ray?

Porcelain gallbladder

What is the term for calcification of the gallbladder wall visible on an X-ray?

TB granuloma or Histoplasmosis

What are two common causes of liver calcifications on an X-ray?

Chronic pancreatitis

Multiple calcifications located midline near the spine on an X-ray suggest what condition?

Aerobilia (Pneumobilia)

What is the term for air seen within the shadow of the liver or branching biliary tree on an X-ray?

Post-surgery (specifically laparoscopic)

In what clinical context is aerobilia a very common and expected finding?

Emphysematous cholecystitis

What condition is characterized by a distended gallbladder lumen and wall filled with air on an X-ray?

Ultrasonography

What is the first-line imaging modality for screening hepatobiliary diseases?

Avoids radiation exposure

Why is ultrasound particularly important for women of reproductive age?

Dynamic assessment (Real-time imaging)

What feature of ultrasound allows for the elicitation of a sonographic Murphy’s sign?

Pain over the gallbladder upon transducer palpation

What defines a positive Murphy’s sign during an ultrasound?

Doppler

Which ultrasound tool is used to assess blood vessel patency and the direction of flow?

Determining hepatic artery thrombosis

How is Doppler ultrasound used after a liver transplant?

Echogenic foci with posterior acoustic shadowing

How do gallstones typically appear on an ultrasound?

Stones move with position; polyps are fixed

How can a clinician differentiate between a gallstone and a polyp in real-time ultrasound?

Precursor to cancer

Why is surgery advised if a gallbladder polyp exceeds 1 cm?

Limited by bowel gas

What is the primary disadvantage of ultrasound when evaluating the pancreas?

Shear wave elastography

Which ultrasound feature measures tissue elasticity to stage liver fibrosis?

Transient Elastography (Liver Fibroscan)

What is currently considered the best noninvasive way to determine liver fibrosis or stiffness?

Ultrasound-Guided Attenuation Parameter (UGAP)

Which tool provides a quantifiable way to measure hepatic steatosis (fatty liver)?

Computed Tomography (CT)

Which modality offers 100-fold better resolution than X-ray and is the choice for liver neoplasms?

Hounsfield units (HU)

What numerical values are generated by CT to indicate the hardness or density of a structure?

Arterial phase

Which CT contrast phase is best for detecting hypervascular lesions like hepatocellular carcinoma?

Portal venous phase

Which CT contrast phase enhances liver parenchyma to detect hypovascular lesions?

Delayed phase

Which CT contrast phase is useful for highlighting fibrosis or bile leaks?

Cross-sectional (Axial)

In what imaging plane are CT scans usually acquired from the patient?

Soft tissue contrast

Magnetic resonance imaging (MRI) is the best tool for dealing with problems related to what?

Contraindication to contrast (Allergies/Kidney problems)

When is non-contrast MRI preferred over CT?

Magnetic Resonance Cholangiopancreatography (MRCP)

What is the non-invasive MRI-based method for imaging bile and pancreatic ducts?

It is diagnostic only and cannot perform interventions

What is the clinical limitation of MRCP compared to ERCP?

Cholangiography

What is the general term for imaging that involves directly injecting dye into the biliary tree?

Endoscopic Retrograde Cholangiopancreatography (ERCP)

Which procedure involves an endoscope inserted through the mouth to inject dye into the CBD?

Papillotomy, stone retrieval, and stent placement

What are three therapeutic interventions possible during an ERCP?

Percutaneous Transhepatic Cholangiography (PTC)

Which procedure involves inserting a needle through the skin into the liver to opacify the bile ducts?

Biliary obstruction needing permanent or temporary drainage

For which patients is PTC typically reserved?

T-tube cholangiography

Which imaging is performed through a surgically placed tube used to anchor the biliary tree post-operation?

Stones appear as dark "filling defects" against bright dye

How do biliary stones appear during a cholangiography?

Nuclear Imaging

Which imaging category is used primarily for determining organ function?

Tc-99m labeled iminodiacetic acid analogs

What specific radiotracers are used in hepatobiliary scintigraphy?

HIDA or DISIDA scan

What is the common name for the cholescintigraphy study used to evaluate biliary excretion?

Biliary atresia and bile leaks

What are two major indications for a HIDA scan in pediatric or post-surgical patients?

Homogeneous echotexture

How is a normal liver described in terms of its ultrasound appearance?

Rough or coarse (magaspang)

How does the liver appear on ultrasound in liver parenchymal disease?

Late-phase cirrhosis

Which condition causes a diffuse small/shrunken liver with wavy borders?

Ascites

What is the term for the dark fluid (black) seen surrounding a shrunken liver in cirrhosis?

Metastasis

Which diffuse liver disease appears as multiple lesions of various sizes involving the entire organ?

Increased echogenicity (Brighter)

How does a fatty liver appear on an ultrasound?

Decreased liver density (Darker/Hypodense)

How does a fatty liver appear on a CT scan?

Starry sky appearance

What is the characteristic ultrasound pattern for acute hepatitis?

Accentuation of portal vessels against dark, edematous parenchyma

What causes the "starry sky" appearance in hepatitis?

Caudate lobe hypertrophy and nodular contours

What are two CT findings characteristic of liver cirrhosis?

Varices

What are the dilated, tortuous collateral vessels seen on a CT of a cirrhotic liver?

Splenomegaly

What splenic finding is frequently associated with portal hypertension in cirrhosis?

Apple-core deformity

Which radiographic sign indicates a focal stricture from an annular malignancy?

Biliary ectasia

What is another term for the dilatation of the biliary system?

Bile ducts dilate >40% of the adjacent portal vein

What is the imaging definition of biliary system dilatation?

Double-duct sign

Which sign describes the simultaneous dilation of both the bile and pancreatic ducts?

Pancreatic Head Cancer

The "double-duct sign" is a classic indicator of which malignancy?

Isolated mass with clear margins

What is a sign of potential resectability for pancreatic carcinoma?

Encasement or obstruction of peripancreatic vessels

What is a definitive sign of non-resectability for pancreatic carcinoma?

Surgery is the only hope for a cure

Why is the radiographic assessment of resectability so critical in pancreatic cancer?

Hepatocellular carcinoma

Which liver neoplasm is CT the imaging of choice to diagnose?

Interlobar fissure

Name the landmark that separates the right and left lobes of the liver anatomically.

Biliary ascariasis

What is the diagnosis for a dense, moving worm-like structure seen in the bile duct on ultrasound?

Ultrasound

Which modality is first-line for identifying gallstones and acute cholecystitis?

MRCP

What is the appropriate imaging modality for diagnosing primary sclerosing cholangitis (PSC)?

Hounsfield units < 40

What CT value range indicates fatty liver disease?