ABSTRACT
Ultrasound is less sensitive than computed tomography (CT) or magnetic resonance imaging (MRI) at detection of diffuse liver diseases and widespread abnormalities such as hepatitis, but National Institute for Health and Care Excellence guidelines suggest its use for monitoring cirrhosis associated with hepatitis B. CT will also detect biliary dilatation and often reveal the cause when ultrasound is unable to do so, e.g. distal common bile duct stone and pancreatic head mass. In an acute setting CT can detect and characterise laceration and haematoma of the liver in trauma, and liver and subphrenic abscess causing acute sepsis. MRI demonstrates the pancreas well but may not practicable or readily available in acutely ill patients with severe pancreatitis where CT remains the predominant modality. MRI can also be used to detect and assess liver masses but is usually a second- or third-line test used when other modalities are inconclusive.
