Abstract
BACKGROUND AND AIMS: Noninvasive preoperative radiologic prediction of histologic grade-a key prognostic factor-is invaluable. We aim to compare the diagnostic values of 3D magnetic resonance elastography (MRE), intravoxel incoherent motion (IVIM), and conventional contrast-enhanced magnetic resonance imaging (cMRI) in predicting the histologic grade of hepatocellular carcinoma (HCC). METHODS: This institutional review board-approved retrospective study included patients who underwent MRI between December 2014 and October 2021. Sixty-eight patients with pathologically confirmed HCCs who underwent MRE, IVIM, and cMRI imaging were included in the analysis. Two radiologists measured HCC stiffness volumetrically and over a single slice, and also measured apparent diffusion coefficient (ADC), IVIM-derived parameters, and enhancement ratio (ER) on arterial phase images via cMRI. Student's t-test or the Mann-Whitney U test was used for group comparisons. Receiver operating characteristic (ROC) curve analyses were performed to evaluate the diagnostic performance. RESULTS: Histologically, fifty-three (78%) patients had well-differentiated or moderately differentiated HCCs, and fifteen (22%) patients had poorly differentiated HCCs. Both the volumetric stiffness and single-ROI tumor stiffness were significantly elevated in the poorly differentiated HCC group (P < 0.001, P = 0.001), and the volumetric stiffness was a better measurement of stiffness because it had a higher ROC curve value (0.816). However, the ADC, the true diffusion coefficient (D), the pseudodiffusion coefficient (D∗), the pseudodiffusion fraction (f), and ER during the arterial phases on cMRI were not significantly different between the two groups (P = 0.309, 0.187, 0.440, 0.350, and 0.714, respectively). CONCLUSIONS: Stiffness measured with 3D MRE may be useful for noninvasively predicting HCC histologic grade, and the volumetric measuring method achieved the highest ROC curve value, outperforming single-ROI HCC stiffness, IVIM parameters, and arterial-phase ER on cMRI.