Interrater reliability and agreement of the liver imaging reporting and data system (LI-RADS) v2018 for the evaluation of hepatic lesions

Introduction
The liver imaging reporting and data system (LI-RADS) is a structured reporting system that categorizes hepatic observations according to major imaging features and lesion size, with an optional ancillary features contribution. This study aimed to evaluate inter-reader agreement of dynamic magnetic resonance imaging (MRI) using LI-RADS v2018 lexicon.

Material and methods
Forty-nine patients with 69 hepatic observations were included in our study. The major and ancillary features of each hepatic observation were evaluated by 2 radiologists using LI-RADS v2018, and the inter-reader agreement was allocated.

Results
The inter-reader agreement of major LI-RADS features was substantial; κ of non-rim arterial hyperenhancement, non-peripheral washout appearance, and enhancing capsule was 0.796, 0.799, and 0.772 (p < 0.001), respectively. The agreement of the final LI-RADS category was substantial with κ = 0.651 (p < 0.001), and weighted κ = 0.786 (p < 0.001). The inter-reader agreement of the ancillary features was substantial to almost perfect (κ range from 0.718 to 1; p < 0.001). An almost perfect correlation was noted for the hepatic lesion size measurement with ICC = 0.977 (p < 0.001).

Conclusions
The major and ancillary features of the LI-RADS v2018, as well as the final category and lesions size, have substantial to almost perfect inter-reader agreement.