E1242. LI-RADS CT/MRI Lexicon Pictoral Review
  1. Jennifer Foley; Naval Medical Center San Diego
  2. Alice Fung; Oregon Health and Science University
  3. Irene Cruite; Inland Imaging
  4. Natally Horvat; Memorial Sloan Kettering Cancer Center
  5. Amita Kamath; Mount Sinai Hospital
  6. Robert Marks; Naval Medical Center San Diego
The American College of Radiology Liver Reporting and Data System (LI-RADS) Lexicon was developed to standardize the reporting of imaging findings in the evaluation and management of hepatocellular carcinoma (HCC). The lexicon was published to facilitate standardization, with defined terms and synonyms (if applicable). Nuances of terms were clarified using specific scenarios and examples. In addition, relevant modalities were assigned to each term. The purpose of this exhibit is to illustrate and define LI-RADS lexicon terms using representative CT and MR images.

Educational Goals / Teaching Points
1. Describe the development and purpose of the ACR Liver Reporting and Data System (LI-RADS) lexicon for CT/MRI, including the context of use for each of the terms. 2. Through CT and MRI examples, LI-RADS lexicon terms will be paired with representative images for visual correlation.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
• Major findings of HCC - Terms will include nonrim arterial phase hyperenhancement, nonperipheral "washout", enhancing capsule appearance, and threshold growth. • Phases of contrast - Terms will include early arterial phase, late arterial phase, portal venous phase, transitional phase, and hepatobiliary phase. • Key LI-RADS terms - Terms will include observation, perfusion alteration, and size. • Terms associated with LI-RADS M and LI-RADS Tumor in Vein (TIV) - Terms will include rim arterial phase hyperenhancement and enhancing soft tissue in vein. • Terms associated with ancillary findings and benign findings in patients at risk for HCC. - Terms will include restricted diffusion, hepatobiliary phase hypointensity, hepatobiliary phase hyperintensity, and peripheral discontinuous nodular enhancement.

The aim of LI-RADS is to enable standardization in terminology, technique and reporting of liver imaging in the detection and evaluation of hepatocellular carcinoma. The lexicon serves to define terms and allow radiologists and clinicians to have a unified understanding of what these terms mean and their context of use. This exhibit will provide high-quality representative images of these terms, facilitating the use of LI-RADS by radiologists worldwide and improving patient care.