Ultrasound Measurement of Liver Size

Measurement Technique

A general-purpose curved array abdominal probe with frequency range of 2-5 MHz is typically used for liver measurement, as recommended by the American College of Emergency Physicians 1, 2
The liver is scanned systematically in real-time through all tissue planes in at least two orthogonal directions, with the probe placed high in the epigastrium and swept laterally while being held immediately adjacent to the costal margin 1
For mid-clavicular line measurement, the liver margin should be maintained within the field of view on the screen, and asking the patient to take and hold a deep breath often improves visualization 1

When the liver margin cannot be visualized below the costal margin, an intercostal approach becomes necessary, with the transducer oriented with the plane of the probe parallel to the ribs and the indicator directed toward the vertebral end of the rib 1

The normal liver is highly variable in size, shape, axis, and location, with a strong correlation between physical examination estimates of liver size and ultrasound measurements, as noted by the American College of Emergency Physicians 1, 2
To avoid confusing the liver with fluid-filled tubular structures, the entire extent of the organ should be scanned in real time in both long and short axes, and a combination of subcostal and intercostal windows allows for views from multiple directions and may help in examining difficult-to-visualize areas 1