ULTRASOUND OF THE LIVER - Normal

For Upper Abdomen Protocol

For Liver Scanning Protocol

For Liver Function Tests explained

LIVER IMAGING

Liver Segmental Anatomy	Click the image to enlarge for a printable version.

PROBE POSITIONING TO SCAN THE LIVER

Rt Lobe Liver

Parasagittal Scan Plane	The Liver and Rt Kidney are visualised in this view.
Intercostal Scan Plane	The Middle and Rt Hepatic Vein are visualised in this view.
Subcostal Scan Plane. The probe is angled cephalad under the ribs to avoid any bowel or ribs shadowing over the liver.	Rt Portal Vein is shown coursing transversely in this view
Left Lobe Of Liver
Scan Plane Left Lobe of Liver. The probe is in the epigastric region just below the sternum. It is angled cephalad to view the left lobe in its entirety. The probe may need to be angled towards the left side to see the most medial edge of the left lobe.	Normal Anatomy seen in the Transverse View of the Left Lobe. Hover the mouse over the image.
The Portal Vein should have constant forward flow into the liver (hepatopetal flow) .As seen in this image, the colour is red ,which is set for movement towards the probe. Be very careful to make sure you look at the colour box on the side of the image to know the setting. If there is flow reversal,this is hepatofugal (tip: Fugitive= run away) and represents portal hypertension.	Because the hepatic veins drain into the IVC immediately prior to the Right Atrium, they have phasic flow reflective of cardiac motion. (Hover over the image for a spectral trace)

Ultrasound of the Liver -Protocol

Role of Ultrasound

 To assess the:

• Size
• Capsular contour (smooth, coarse, lobulated)
• Parenchymal echogenicity
• Vascularity
• Biliary tree
• Masses or collections

Limitations

• Obesity and patients with severe cases of metabolic disorders such as haemochromatosis and fatty infiltration will reduce detail and the diagnostic yield of the scan.

Preparation

• Ideally, fast the patient for 6hours to reduce bowel gas and prevent gall bladder contraction.

Equipment Selection

• Depending on the size of the patient a curved linear array 2-6Mhz.
• If there is nodularity of the liver border then a linear array with a 7-12MHZ frequency will better appreciate this. Good colour / power / Doppler capabilities when assessing vessels or vascularity of a structure.
• Be prepared to change focal zone position and frequency output of probe (or probes) to adequately assess both superficial and deeper structures.

Scanning Technique

Begin doing a full sweep through the liver.

You will need the patient to take deep inspirations to fully visualise the superior borders of the liver.

Look in transverse up and down the left lobe from a subcostal approach. Look in transverse through the right lobe subcostally or intercostally.

Roll the patient in a left lateral decubitus position for assessment of the Rt lobe only after checking for fluid. Bowel gas can overlie the liver in a subcostal approach, so getting the patient to distend their abdomen can help with visualisation. Also looking intercostally between each rib space can ensure thorough visualisation.
Look For:

• Homogeneous v's Attenuative(normal v's fatty)

• Smooth v's coarse echotexture
bmode image here
• Size: To measure the size of the liver, use a sagittal approach in the mid clavicular line. Measure from the diaphragm to the inferior border on bmode image. This can be very subjective. Also look at the lower edge of liver in relation to the Rt kidney.It should finish half way down the kidney. Bmode image an enlarged liver will have rounded borders.

Once you have thoroughly scanned though the liver, then start taking images.


Document the normal anatomy and any pathology found, including measurements and vascularity if indicated.

Common Pathology

• Fatty liver
• Liver cysts
• Haemangioma
• Portal hypertension
• Portal vein thrombosis
• Hepatic vein thrombosis
• Liver abscess/collection
• Cirrhosis
• Trauma
• Metastases
• HCC
• Abscess

Basic Hard Copy Imaging

An liver series should include the following minimum images;

• Longitudinal
  • Left lobe
  • Caudate lobe
  • IVC
  • Porta hepatis
  • Comparison to Rt Kidney
• Transverse
  • Left lobe
  • Left hepatic vein
  • Left portal vein
  • Right portal vein
• Middle and Right hepatic vein