Letter to the Editor: “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”

by Maria Alejandra Rueda M.D., Sergio Valencia M.D. M.Sc., Julian Guerra M.D, Gustavo Trianna M.D. M.Sc. (mariarueda91@gmail.com)

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

Dear Editor,

We have read with great interest the article entitled “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” by Fraum et al [1]. We would like to appreciate the author’s efforts in pointing out the importance of evaluating the sensitivity of LI-RADS features to categorize the likelihood of a malignant lesion other than hepatocellular carcinoma in patients considered high risk versus not high risk. We were surprised to see that the majority of the LR-M features were seen in patients without risk factors, however, there was a big discrepancy in the ancillary features favoring malignancy, non-HCC. Based on your results, non-HCC PLCs were more likely to mimic HCCs on CT and MRI in the LI-RADS target population than in patients. This raises the question whether a different value should be given to the LR-M features and the ancillary features. Is it worth trying to individually assess the LR-M and ancillary features of LI-RADS in patients with and without risk factors independently to determine the need of revising these criteria or creating a new classification system to detect other non-HCC malignancies?

We had several concerns respecting the statistical aspect of the study. Given that the kappa agreement for all mayor features except size was (κ, 0.31 to 0.55), it makes us think that there is a discrepancy in the interpretation of the mayor features or LIRADS between the two observers. Additionally, the poor kappa values for LR-M features and ancillary features makes us think that it is still not possible to determine whether LI-RADS imaging features of primary liver carcinomas other than hepatocellular carcinoma differ between patients considered high risk versus not high risk and whether there were correctly interpreted. We believe that the evaluation of the LI-RADS features requires multiple observers with different levels of expertise and backgrounds for a more robust evaluation as addressed by Obuchowski [2].

It is important for the authors to elucidate how many lesions were asses by CT and MRI and whether the results varied in the different imaging modalities given that sensitivity and specify of MRI is higher than CT [3]. Finally, we would also like to know if the LR-M reporting criteria for the differential diagnosis was used since this could affect the miscategorized lesions.