Fraum TJ, Cannella R, Ludwig DR, Tsai R, Naeem M, LeBlanc M, Salter A, Tsung A, Shetty AS, Borhani AA, Furlan A, Fowler KJ. 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. Eur Radiol. 2019 Oct 25. doi: 10.1007/s00330-019-06448-6. PubMed PMID: 31654212.
OBJECTIVES: 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.
METHODS: 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.
RESULTS: 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).
CONCLUSIONS: 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.
KEY POINTS: €¢ 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.
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