Abdominal ultrasound scans for diagnostic imaging of the liver

Abstract

Ultrasound is a common first-line imaging investigation that uses sound waves to produce an image (sonogram) of the internal organs. It is easy, quick and cost-effective to perform and safe, non-invasive and generally painless for the patient. Abdominal ultrasound in particular visualises the hepatobiliary system. It is used to investigate abdominal pain, abnormal liver function tests, distension and jaundice, as well as to screen for hepatocellular carcinoma and abdominal aortic aneurysm. Ultrasound requests should include relevant clinical background information to ensure the patient receives the right test and help the sonographer rule out differential diagnoses. Before the test, patients should be given all available information and asked to fast for 6–8 hours, although clear fluids are permitted. The scan usually procedure takes 15–30 minutes but may be extended depending on pathology identified. The sonogram displays the comparative echogenicity of the liver and adjacent organs in real time. Increased echogenicity, a coarse echotexture and a saw-tooth liver edge are indicative of liver pathology. Ultrasound can also allow the assessment of the portal venous system to exclude portal vein thrombus or elevated portal velocities. Advanced clinical nurse practitioners can order ultrasounds in line with local hospital trust guidance, which may include Ionising Radiation Medical Exposure Regulations (IRMER) training.