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Liver Imaging with LI-RADS

Chronic liver disease, or cirrhosis, is when healthy liver is replaced by scar tissue. This scar tissue stops the liver from working normally. It may also lead to liver cancer or even death.

People with cirrhosis are at high risk for two types of liver cancer. Hepatocellular carcinoma (HCC), which begin in the cells of the liver, and cholangiocarcinoma, which begins in the bile ducts inside the liver.

If you have chronic liver disease, your doctor will monitor you with blood tests and medical imaging to look for changes in the liver. Your doctor may use ultrasound (US), CT, and/or MRI to image your liver. After the exam, the radiologist will analyze the images and prepare a report summarizing the findings and impressions. For more information on your imaging report, see How to Read Your Radiology Report.

LI-RADS and Liver Imaging

If you are at high risk for HCC, the radiologist reading your imaging report will use the Liver Imaging Reporting and Data System, or LI-RADS. LI-RADS is a common language developed by experts in liver imaging and liver disease. It helps eliminate mistakes and improve communication between members of your care team.

The radiologist will assign a LI-RADS number or letter category to each lesion (which may also be called a mass, nodule, or observation) seen on the images. Your report may include more than one LI-RADS category because people with cirrhosis can have many different types of lesions in their liver. These LI-RADS categories may change from one imaging exam to the next. In patients with chronic liver disease, the way a mass looks can change over time.

Doctors only use LI-RADS for patients who have cirrhosis or who are at high risk of developing HCC. (No LI-RADS categories will appear if the patient is not at increased risk for HCC or is under the age of 18.)

Doctors use LI-RADS for people at high risk for HCC, including: Doctors do not use LI-RADS for:
  • cirrhosis from known causes.
  • chronic hepatitis B viral infection.
  • a history of HCC.
  • a patient on the list for liver transplant.
  • a patient who has received a liver transplant.
  • patients under 18.
  • cirrhosis caused by a condition you were born with.
  • a cancer which has been biopsied or surgically removed.
  • a benign lesion that did not develop from liver cells and was biopsied or surgically removed.

LI-RADS for Ultrasound (US)

Doctors use US to look for early signs of cancer in high-risk patients and to closely watch a diseased liver. US images cannot determine whether a lesion is cancer. If a lesion is found, your doctor may order a CT or MRI.

LI-RADS categories for US range from 1 to 3:

  • 1: no evidence of cancer. Follow-up US in 6 months is typically recommended.
  • 2: a small mass less than 1 cm. Follow-up US is recommended in 3-6 months.
  • 3: a large mass more than 1 cm. Further imaging with contrast is recommended.

Your US study may also have a letter. This letter indicates if the radiologist was able to clearly see the liver or if the images were limited in some way.

Letter categories for US range from A to C:

  • A: no or minimal limitations
  • B: moderate limitations
  • C: severe limitations

LI-RADS for CT and MRI

Liver lesions seen on CT and MRI are categorized from 1 to 5:

  • LR-1: definitely not cancer (benign)
  • LR-2: probably not cancer
  • LR-3: intermediate probability of HCC
  • LR-4: probably HCC
  • LR-5: definitely HCC

Letters are used to describe other findings:

  • LR-M: the lesion looks like a malignant cancer other than HCC. An image-guided biopsy is typically recommended.
  • LR-TIV: cancer has spread into the blood vessels of the liver.
  • LR-NC: the abnormality could not be evaluated. This may happen when the image is blurry or not high enough in quality.

LI-RADS for Post-Treatment Imaging

When a patient treated for liver cancer has follow-up imaging, radiologists use the LI-RADS category "TR" (for treatment response). TR categories report how a tumor responded to treatment:

  • LR-TR Non-evaluable: The treatment response cannot be evaluated because of poor image quality.
  • LR-TR Nonviable: There is no remaining cancer.
  • LR-TR Viable: There is a high likelihood of cancer at the treatment site.
  • LR-TR Equivocal: The radiologist is not sure if there is remaining cancer at the treatment site. More imaging is usually needed.

This page was reviewed on November 01, 2019


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