Introduction to the Liver Imaging Reporting and Data System for Hepatocellular Carcinoma

Abstract

The Liver Imaging Reporting And Data System (LI-RADS) was created with the support of the American College of Radiology (ACR) to standardize the acquisition, interpretation, reporting, and data collection for imaging examinations in patients at risk for hepatocellular carcinoma (HCC). A comprehensive and rigorous system developed by radiologists, hepatologists, pathologists, and surgeons, LI-RADS addresses a wide range of imaging contexts. Currently, 4 algorithms are available publicly on the ACR website: ultrasound for HCC surveillance, computed tomography and magnetic resonance imaging for HCC diagnosis and tumor staging, contrast-enhanced ultrasound for HCC diagnosis, and computed tomography/ magnetic resonance imaging for treatment response assessment. Each algorithm is supported by a decision tree, categorization table, lexicon, atlas, technical requirements, and reporting and management guidance. Category codes reflecting the relative probability of HCC and malignancy are assigned to imaging-detected liver observations, with emerging evidence suggesting that LI-RADS accurately stratifies HCC and malignancy probabilities. LI-RADS is an evolving system and has been updated and refined iteratively since 2011 based on scientific evidence, expert opinion, and user feedback, with input from the American Association for the Study of Liver Diseases and the Organ Procurement Transplantation Network/United Network for Organ Sharing. Concurrent with its most recent update, LI-RADS was integrated into the American Association for the Study of Liver Diseases HCC guidance released in 2018. We anticipate continued refinement of LI-RADS and progressive adoption by radiologists worldwide, with the eventual goal of culminating in a single unified system for international use.

Contrast-enhanced ultrasound liver reporting and data system for hepatocellular carcinoma diagnosis

“…Structured reporting systems such as BI-RADS® and LI-RADS® emerged due to the need for increased consistency of imaging diagnostics [18] . These systems typically are created based on existing data and expertise, but the validation of real-world use is critical.…”

“…The American College of Radiology (ACR) Liver Reporting and Data System (LI-RADS®) was created as a standardized reporting system to facilitate consistent and high-quality technique, interpretation, reporting, and data collection for diagnosis of HCC in patients at risk of HCC, initially for CT and MRI in 2011 [18] . Recognizing the value and worldwide utilization of CEUS to diagnose HCC, ACR convened a Working Group of international experts in CEUS to develop CEUS LI-RADS® starting in April 2014.…”

Controversies in the management of hepatocellular carcinoma

“…8 Finally, the Liver Imaging Reporting and Data System (LI-RADS) proposed by the American College of Radiology was developed and repeatedly updated to enable the homogeneous reporting of imaging techniques for the diagnosis of hepatic nodules in patients at risk of HCC. 38,39 LI-RADS addresses the full spectrum of liver lesions, classifying the observations into 5 categories, from LR-1 (definitely benign) to LR-5 (definitely HCC). Between both of them we find LR-2 (probably benign), LR-3 (intermediate probability of HCC) and LR-4 (probably HCC) with a progressive increase of HCC risk through the different categories.…”

Detect or not to detect very early stage hepatocellular carcinoma? The western perspective

“…For lesion between 1 and 2 cm, non-rim arterial phase hyperenhancement and one more feature (non-peripheral washout or threshold growth) are diagnostic for HCC (Fig. 1) [28]. The non-invasive criteria should be applied only in patients with underlying cirrhosis of the liver given high pretest probability.…”

“…LI-RADS system classifies lesions into 7 different categories (Fig. 2) [28,55]. LI-RADS 1 lesions are definitively benign and return to regular surveillance imaging every 6 months is recommended.…”