Ultrasonography is a valuable tool for the diagnosis of liver disease. Discrete or diffuse lesions can be imaged, aspirated, and biopsied under visual guidance. The ultrasonographic examination of the liver is performed on the right side of the standing animal using a real-time 3.5 to 5.0 MHz linear or convex transducer. This imaging modality also can be used to aspirate bile from the gallbladder for the diagnosis of liver flukes. Ultrasonography cannot be used to evaluate liver regions obscured by the lungs, however.