Ultrasound

• Is the first and the most commonly obtained method of examination in patients with RUQ pains, abnormal LFTs, or suspected liver masses.
   
• Is a noninvasive and excellent screening tool.
   
• Used to evaluate the presence of bile duct obstruction and gallstones as well as to distinguish a solid lesion from a cystic one.
   
• Has low sensitivity and high false negative rate for detection of liver metastases.
   
• 6 common causes of homogeneously increased echogenicity of the liver are:
  • Fatty infiltration
  • Cirrhosis
  • Hepatitis (sometimes)
  • Amyloidosis
  • Leukemic infiltration (often normal to low echogenicity)
  • Hemochromatosis
     
• Ultrasound Doppler imaging can be very helpful in identifying vascular abnormalities, i.e. patency of hepatic vessels, portal vein, and IVC as well as flow direction in these vessels. Flow in the portal vein and hepatic arteries are hepatopedal (toward the liver) while flow in hepatic veins and hepatic ducts are hepatofugal (away from the liver).

• In color Doppler imaging, shades of red typically refer to blood flowing toward the transducer, whereas shades of blue refer to blood flowing away from the transducer.
   
• Commonly used terminology in U/S: echogenic, anechoic, hyper/hypoechoic, acoustic shadow....