Assessment of primary liver carcinomas other than hepatocellular carcinoma (HCC) with LI-RADS v2018: comparison of the LI-RADS target population to patients without LI-RADS-defined HCC risk factors
To determine whether the LI-RADS imaging features of primary liver carcinomas (PLCs) other than hepatocellular carcinoma (non-HCC PLCs) differ between patients considered high risk (RF+) versus not high risk (RF−) for HCC and to compare rates of miscategorization as probable or definite HCC between the RF+ and RF− populations.
This retrospective study included all pathology-proven non-HCC PLCs imaged with liver-protocol CT or MRI from 2007 to 2017 at two liver transplant centers. Patients were defined per LI-RADS v2018 criteria as RF+ or RF−. Two independent, blinded readers (R1, R2) categorized 265 lesions using LI-RADS v2018. Logistic regression was utilized to assess for differences in imaging feature frequencies between RF+ and RF− patients. Fisher’s exact test was used to assess for differences in miscategorization rates.
Non-HCC PLCs were significantly more likely to exhibit nonrim arterial phase hyperenhancement (R1: OR = 2.94; R2: OR = 7.09) and nonperipheral “washout” (R1: OR = 3.65; R2: OR = 7.69) but significantly less likely to exhibit peripheral “washout” (R1: OR = 0.30; R2: OR = 0.10) and delayed central enhancement (R1: OR = 0.18; R2: OR = 0.25) in RF+ patients relative to RF− patients. Consequently, non-HCC PLCs were more often miscategorized as probable or definite HCC in RF+ versus RF− patients (R1: 23.3% vs. 3.6%, p < 0.001; R2: 11.0% vs. 2.6%, p = 0.009).
Non-HCC PLCs are more likely to mimic HCCs on CT and MRI in the LI-RADS target population than in patients without LI-RADS-defined HCC risk factors.
• The presence of LI-RADS-defined risk factors for HCC tends to alter the imaging appearances of non-HCC PLCs, resulting in higher frequencies of major features and lower frequencies of LR-M features.
• Non-HCC PLCs are more likely to be miscategorized as probable or definite HCC in the LI-RADS target population than in patients without LI-RADS-defined HCC risk factors.
KeywordsBile duct neoplasms Liver neoplasms Cholangiocarcinoma Carcinoma, hepatocellular Liver cirrhosis
Arterial phase hyperenhancement
Liver Imaging Reporting and Data System
LI-RADS category indicating that lesion is likely malignant but not necessarily HCC
LI-RADS-defined risk factors for HCC absent
LI-RADS-defined risk factors for HCC present
The authors state that this work has not received any funding. Dr. Ludwig receives salary support from the Training OPportunities in Translational Imaging Education and Research (TOP-TIER) Holden Thorp grant at Washington University.
Compliance with ethical standards
The scientific guarantor of this publication is Dr. Fraum.
Conflict of interest
The authors declare that they have no conflict of interest.
Statistics and biometry
One of the authors (Dr. Salter) has significant statistical expertise.
Written informed consent was waived by the Institutional Review Board.
Institutional Review Board approval was obtained.
Study subjects or cohorts overlap
In a study previously published in Abdominal Radiology, we reported on the 48 cHCC-CCAs and 25 iCCAs from the at-risk cohort in the current study. Additionally, we have a manuscript accepted (currently in press) by HPB that includes 20 of 44 cHCC-CCAs and 84 of 148 iCCAs from the not at-risk cohort in the current study. Importantly, both this previously published study and the in press manuscript focus on the diagnostic accuracy of LI-RADS v2018 for differentiating HCCs from non-HCC malignancies. In contrast, the current manuscript focuses exclusively on the non-HCC malignancies and addresses a completely different question (specifically, whether there are significant differences in the imaging appearances non-HCC PLCs in the at-risk versus not at-risk cohorts).
• Diagnostic or prognostic study
• Multicenter study
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