Evidence Supporting LI-RADS Major Features for CT- and MR Imaging-based Diagnosis of Hepatocellular Carcinoma: A Systematic Review

Abstract

The Liver Imaging Reporting and Data System (LI-RADS) standardizes the interpretation, reporting, and data collection for imaging examinations in patients at risk for hepatocellular carcinoma (HCC). It assigns category codes reflecting relative probability of HCC to imaging-detected liver observations based on major and ancillary imaging features. LI-RADS also includes imaging features suggesting malignancy other than HCC. Supported and endorsed by the American College of Radiology (ACR), the system has been developed by a committee of radiologists, hepatologists, pathologists, surgeons, lexicon experts, and ACR staff, with input from the American Association for the Study of Liver Diseases and the Organ Procurement Transplantation Network/United Network for Organ Sharing. Development of LI-RADS has been based on literature review, expert opinion, rounds of testing and iteration, and feedback from users. This article summarizes and assesses the quality of evidence supporting each LI-RADS major feature for diagnosis of HCC, as well as of the LI-RADS imaging features suggesting malignancy other than HCC. Based on the evidence, recommendations are provided for or against their continued inclusion in LI-RADS. ^© RSNA, 2017 Online supplemental material is available for this article.

Figure 1a:

(a) Schematic of APHE (arrows). (b) Images in a 53-year-old man with HCC and hepatitis C virus cirrhosis. T1-weighted three-dimensional gradient-recalled echo images with fat suppression obtained in (from left to right) unenhanced, late arterial, portal venous, and 3-minute delayed phases after administration of gadolinium-based contrast agent show APHE (arrow) in the late arterial phase. LI-RADS schematic reproduced with permission from the American College of Radiology.

Figure 1b:

(a) Schematic of APHE (arrows). (b) Images in a 53-year-old man with HCC and hepatitis C virus cirrhosis. T1-weighted 3D gradient-recalled echo images with fat suppression obtained in (from left to right) unenhanced, late arterial, portal venous, and 3-minute delayed phases after administration of gadolinium-based contrast agent show APHE (arrow) in the late arterial phase. LI-RADS schematic reproduced with permission from the American College of Radiology.

Figure 2:

Schematic of observation diameter indicating measurement conventions recommended in LI-RADS (arrows). LI-RADS schematic reproduced with permission from the American College of Radiology.

Figure 3a:

(a) Schematic of APHE (all rows) and washout appearance (arrows) of entire observation in portal venous and delayed phase (top row), washout in delayed phase (middle row), and washout in delayed phase relative to liver parenchyma which consists of nodules and fibrosis (bottom row). (b) Images in a 57-year-old man with HCC and hepatitis C virus cirrhosis. Axial CT images obtained in (from left to right) unenhanced, late arterial, portal venous, and 3-minute delayed phases after administration of an iodinated contrast agent show washout appearance most conspicuous in the 3-minute delayed phase (arrow). LI-RADS schematic reproduced with permission from the American College of Radiology.

Figure 3b:

(a) Schematic of APHE (all rows) and washout appearance (arrows) of entire observation in portal venous and delayed phase (top row), washout in delayed phase (middle row), and washout in delayed phase relative to liver parenchyma which consists of nodules and fibrosis (bottom row). (b) Images in a 57-year-old man with HCC and hepatitis C virus cirrhosis. Axial CT images obtained in (from left to right) unenhanced, late arterial, portal venous, and 3-minute delayed phases after administration of an iodinated contrast agent show washout appearance most conspicuous in the 3-minute delayed phase (arrow). LI-RADS schematic reproduced with permission from the American College of Radiology.

Figure 4a:

(a) Schematic of observations with (top three rows) and without (bottom row) capsule appearance. Observations with “capsule” (arrows) show unequivocal peripheral rim enhancement in portal venous phase or delayed phase. The degree of enhancement usually is greater in the delayed phase than in the portal venous phase. Such observations may have APHE (top row and third row) or arterial phase iso- or hypoenhancement (second row). A rim of APHE also may be present. However, if rim enhancement is only seen in the arterial phase (bottom row), this should not be characterized as “capsule.” (b) Images in a 54-year-old man with HCC and hepatitis C virus. T1-weighted 3D gradient-recalled echo images with fat suppression obtained in (from left to right) unenhanced, late arterial, portal venous, and 3-minute delayed phase after administration of gadolinium-based contrast agent show capsule appearance in portal venous and delayed phases (arrows). LI-RADS schematic reproduced with permission from the American College of Radiology.

Figure 4b:

(a) Schematic of observations with (top three rows) and without (bottom row) capsule appearance. Observations with “capsule” (arrows) show unequivocal peripheral rim enhancement in portal venous phase or delayed phase. The degree of enhancement usually is greater in the delayed phase than in the portal venous phase. Such observations may have APHE (top row and third row) or arterial phase iso- or hypoenhancement (second row). A rim of APHE also may be present. However, if rim enhancement is only seen in the arterial phase (bottom row), this should not be characterized as “capsule.” (b) Images in a 54-year-old man with HCC and hepatitis C virus. T1-weighted 3D gradient-recalled echo images with fat suppression obtained in (from left to right) unenhanced, late arterial, portal venous, and 3-minute delayed phase after administration of gadolinium-based contrast agent show capsule appearance in portal venous and delayed phases (arrows). LI-RADS schematic reproduced with permission from the American College of Radiology.

Figure 5:

Schematic illustrates the three LI-RADS definitions of threshold growth: increase in diameter of a mass compared with its baseline by a minimum of 5 mm and by at least 50% diameter increase if time interval is less than 6 months (top row) or by at least 100% diameter increase if more than 6 months (middle row). In addition, a new mass measuring at least 10 mm that was previously unseen within the last 24 months also represents threshold growth (bottom row). LI-RADS schematic reproduced with permission from the American College of Radiology.

Figure 6:

Graph of HCC TVDT (expressed in days) in observational studies. The median doubling time of primary HCC is 178 days and that of recurrent HCC is 82 days.