Validation of proposed imaging criteria for estimating vessels encapsulating tumor clusters in hepatocellular carcinoma at CT and gadoxetic acid-enhanced MRI

Abstract

Purpose

Vessels encapsulating tumor clusters (VETC) was implicated in the unfavourable prognosis of hepatocellular carcinoma (HCC). While potentially valuable for noninvasive evaluation, the proposed imaging criteria of VETC require external validation. This study aimed to evaluate the performance and prognostic value of these imaging criteria via CT and gadoxetic acid-enhanced MRI.

Methods

Retrospectively, we gathered study included 191 patients with a single HCC who underwent preoperative CT and gadoxetic acid-enhanced MRI at three tertiary care centers between January 2017 and May 2021. The performance of previously reported radiological feature-based criteria of VETC, including the SN (size and necrosis) score, the VETC nomogram, and Fan’s model, were evaluated using the area under the curve (AUC) and compared using the DeLong method. Imaging estimated VETC stratification was assessed for its association with early recurrence.

Results

Ninety-four patients (49.2%) were pathologically identified as VETC-positive HCC. No significant differences were found between CT and gadoxetic acid-enhanced MRI regarding the performance of the criteria (all P > 0.05). However, the VETC nomogram, which incorporates tumor size, necrosis, and enhancement pattern, outperformed the SN score and Fan’s model (AUC: 0.825 vs. 0.716 and 0.588 at CT; 0.841 vs. 0.721 and 0.621 at gadoxetic acid-enhanced MRI, both P < 0.001). Stratification using the VETC nomogram, validated on both CT and gadoxetic acid-enhanced MRI, was associated with early recurrence (P < 0.05).

Conclusion

This study confirmed that the radiological feature-based criteria of VETC in HCC are applicable to both CT and gadoxetic acid-enhanced MRI, with the VETC nomogram showing strong discriminatory power in identifying VETC-positive HCC and predicting early recurrence.