A Multicenter Assessment of Interreader Reliability of LI-RADS Version 2018 for MRI and CT.

Background Various limitations have impacted research evaluating reader agreement for Liver Imaging Reporting and Data System (LI-RADS). Purpose To assess reader agreement of LI-RADS in an international multicenter multireader setting using scrollable images. Materials and Methods This retrospective study used deidentified clinical multiphase CT and MRI and reports with at least one untreated observation from six institutions and three countries; only qualifying examinations were submitted. Examination dates were October 2017 to August 2018 at the coordinating center. One untreated observation per examination was randomly selected using observation identifiers, and its clinically assigned features were extracted from the report. The corresponding LI-RADS version 2018 category was computed as a rescored clinical read. Each examination was randomly assigned to two of 43 research readers who independently scored the observation. Agreement for an ordinal modified four-category LI-RADS scale (LR-1, definitely benign; LR-2, probably benign; LR-3, intermediate probability of malignancy; LR-4, probably hepatocellular carcinoma [HCC]; LR-5, definitely HCC; LR-M, probably malignant but not HCC specific; and LR-TIV, tumor in vein) was computed using intraclass correlation coefficients (ICCs). Agreement was also computed for dichotomized malignancy (LR-4, LR-5, LR-M, and LR-TIV), LR-5, and LR-M. Agreement was compared between research-versus-research reads and research-versus-clinical reads. Results The study population consisted of 484 patients (mean age, 62 years ± 10 [SD]; 156 women; 93 CT examinations, 391 MRI examinations). ICCs for ordinal LI-RADS, dichotomized malignancy, LR-5, and LR-M were 0.68 (95% CI: 0.61, 0.73), 0.63 (95% CI: 0.55, 0.70), 0.58 (95% CI: 0.50, 0.66), and 0.46 (95% CI: 0.31, 0.61) respectively. Research-versus-research reader agreement was higher than research-versus-clinical agreement for modified four-category LI-RADS (ICC, 0.68 vs 0.62, respectively; P = .03) and for dichotomized malignancy (ICC, 0.63 vs 0.53, respectively; P = .005), but not for LR-5 (P = .14) or LR-M (P = .94). Conclusion There was moderate agreement for LI-RADS version 2018 overall. For some comparisons, research-versus-research reader agreement was higher than research-versus-clinical reader agreement, indicating differences between the clinical and research environments that warrant further study. © RSNA, 2023 Supplemental material is available for this article. See also the editorials by Johnson and Galgano and Smith in this issue.

What proportion of LI-RADS 5 observations reported in clinical practice do not meet LI-RADS 5 criteria?

OBJECTIVES: Liver Imaging Reporting and Data System (LI-RADS, LR) category 5 (definite hepatocellular carcinoma [HCC]) is assigned based on combinations of major imaging features (MFs): size, arterial-phase hyperenhancement (APHE), washout (WO), enhancing capsule, and threshold growth. The criteria were simplified in v2018 compared to v2017. The goal of this study is to assess the proportion of LR-5 observations reported in clinical practice with LI-RADS v2017 or v2018 that did not meet LR-5 criteria based on reported MFs. METHODS: All MR and CT reports using a standardized LI-RADS template between April 2017 and September 2020 were identified retrospectively. For each reported LR-5 observation, size, MFs, and LI-RADS version (v2017 or v2018) were extracted. Reported MFs were used to determine whether LR-5 criteria were met using the applied version of LI-RADS. The data was summarized descriptively. RESULTS: Three hundred eight observations in 234 patients (67.6% male, mean age 66.2 years) were reported as LR-5, including 136 (44.2%) with v2017 and 172 (55.8%) with v2018. 8/136 (6%) v2017 LR-5 observations and 6/172 (3%) v2018 LR-5 observations did not meet LR-5 criteria. Of 8 incorrectly categorized v2017 observations, 3 (43%) lacked APHE, 1 (14%) was a 16-mm new observation with APHE only, and 4 (43%) were 10-19 mm with APHE and WO. Of the 6 incorrectly categorized v2018 observations, 5 (83%) lacked APHE and 1 (17%) was < 10 mm. CONCLUSIONS: Depending on the LI-RADS version, 3-6% of LR-5 observations reported in clinical practice do not meet LR-5 criteria based on reported MFs. Key Points • Depending on the LI-RADS version, 3-6% of LR-5 observations in clinical practice do not meet LR-5 criteria based on reported major imaging features. • Assigning LR-5 category to observations without nonrim arterial-phase hyperenhancement was the most common error.

Prevalence of different LI-RADS v2018 categories in high-risk patients undergoing CT- or MRI-based screening for hepatocellular carcinoma.

PURPOSE: To estimate the prevalence of Liver Imaging Reporting and Data System (LI-RADS, LR) v2018 categories reported on CT or MRI performed for hepatocellular carcinoma (HCC) screening. MATERIALS AND METHODS: This retrospective study included all reports for CT and MRI exams performed for HCC screening patients between 8/2018 and 4/2020. Patients with ultrasound, CT, or MRI of the abdomen within two years of the index exam were excluded. From each radiology report, we extracted number of reported liver observations, and LI-RADS v2018 category for each observation. RESULTS: There were 329 patients (170 [52%] male, mean age 59 years [SD 12]), of whom 177 (54%) had MRI with gadoxetate, 72 (22%) had MRI with extracellular contrast, 7 (2%) had MRI with unspecified contrast, and 73 (22%) had CT. Of 329 patients, 199 (60%) had no reported observations; 130 patients had 166 reported observations: 114 (68.7%) LR-1, 8 (4.8%) LR-2, 21 (12.6%) LR-3, 6 (3.6%) LR-4, 13 (7.8%) LR-5, 3 (1.8%) LR-M, and 1 (0.6%) LR-TIV. Of 114 LR-1 observations, 78 (68%) were cysts, 17 (15%) were hemangiomas, 12 (11%) were vascular shunts, 3 (3%) were focal nodular hyperplasia, 2 (2%) were siderotic nodules, 1 (1%) was a lipoma, and 1 (1%) was biliary hamartoma. There were 23 observations with probably or definitely malignant categories (LR-4, LR-5, LR-M or LR- TIV), reported in 20/329 (6%) of patients. CONCLUSION: In a cohort of at-risk patients undergoing contrast-enhanced CT/MRI for HCC screening, 60% of had no liver observations, and 6 % had probably or definitely malignant observations. IMPLICATIONS FOR PATIENT CARE: The prevalence of LI-RADS v2018 categories on CT or MR exams used for HCC screening can help develop screening criteria and assess cost-effectiveness of surveillance strategies with CT and MRI.