MRI Findings and Prediction of Time to Progression of Patients with Hepatocellular Carcinoma Treated with Drug-eluting Bead Transcatheter Arterial Chemoembolization

Abstract

The purpose of this study was to investigate the utility of MRI findings after drug-eluting beads (DEB) - transcatheter arterial chemoembolization (TACE) for hepatocellular carcinoma in predicting time to progression (TTP). This study included 48 patients with 60 lesions who underwent liver MRI within 3 months after DEB-TACE. MRI was assessed for arterial enhancement pattern, late washout, arterioportal shunt, signal intensity on T2-weighted image, intratumoral septa, enhancing tissue on subtraction images, and treatment response. Cox-regression analysis was performed to identify independent factors to predict TTP. TTP was calculated using the Kaplan-Meier method with the log-rank test. Per lesion, 30 achieved complete remission, 22 had a partial response, and the remaining 8 lesions displayed stable disease on MRI. Arterial enhancement pattern, washout and enhancing tissue on subtraction images from MRI were associated with viable tumor on the last follow-up computerized tomography. Arterial enhancement, washout and enhancing tissue on subtraction images were significant predictors of TTP, but only enhancing tissue on subtraction images remained a significant predictor of TTP (P=0.018) in the multivariate analysis. TTP was longer in the group without enhancing tissue on subtraction images compared to the group with enhancing tissue (601 days vs. 287 days, P<0.001). Enhancing tissue on subtraction images from MRI after DEB-TACE is predictive for longer TTP.

Keywords: Carcinoma, Hepatocellular; Drug-eluting Beads; Magnetic Resonance Imaging; Subtraction Image; Transcatheter Arterial Chemoembolization.

Fig. 1. A 61-yr-old man treated with DEB-TACE for HCC. (A) An arterial enhancing mass (white arrowhead) is noted on the MRI obtained before DEB-TACE. (B, C) The treated lesion shows peripheral rim enhancement on arterial phase (white arrow) (B), and equilibrium phase (C) of axial fat-suppressed T1-weighted 3D GRE images in the follow-up MRI acquired 36 days after DEB-TACE. (D) Rim enhancement (white arrow) is identified as being more prominent on the subtraction image between the precontrast image and the arterial phase image. (E) The treated lesion shows high-signal intensity on T2-weighted image. Tumor response was determined as complete response on the first follow-up MRI.

Fig. 2. A 68-yr-old man treated with DEB-TACE for HCC. (A) A large HCC with heterogeneous enhancement in the right lobe of the liver is noted on the arterial phase image of the CT obtained before DEB-TACE. (B-C) After DEB-TACE, near total necrosis is achieved in the tumor, but a small nodular portion with enhancement (white arrow) on arterial phase (B) and late washout on equilibrium phase (C) of axial fat-suppressed T1-weighted 3D GRE images remains in the periphery of the tumor on the follow-up MRI taken 30 days after TACE. (D) Arterial enhancement of the residual tumor (white arrow) is accentuated on the subtraction image. (E) The residual viable portion of tumor on T2-weighted image shows low signal intensity with peripheral dark rim (white arrow). (F) Treatment response of HCC after DEB-TACE was determined to be a partial response. Residual tumor with arterial enhancement increased on a follow-up CT taken 66 days after DEB-TACE.

Fig. 3. A 67-yr-old woman treated with DEB-TACE for HCC. (A) HCC is noted on the arterial phase image of the liver MRI acquired prior to treatment. (B) After DEB-TACE, an enhancing portion within the treated tumor is not detected on the arterial phase. (C) Meanwhile, subtle washout is suspected on the equilibrium phase of a follow-up MRI taken 30 days after DEB-TACE. (D) A small arterial enhancing portion is noted on the subtraction image. (E) Detecting residual tumor on axial T2-weighted image is difficult.