AUTHOR=Cheung Andy Lai-Yin , Zhang Lei , Liu Chenyang , Li Tian , Cheung Anson Ho-Yin , Leung Chun , Leung Angus Kwong-Chuen , Lam Sai-Kit , Lee Victor Ho-Fun , Cai Jing 

TITLE=Evaluation of Multisource Adaptive MRI Fusion for Gross Tumor Volume Delineation of Hepatocellular Carcinoma

JOURNAL=Frontiers in Oncology

VOLUME=Volume 12 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/oncology/articles/10.3389/fonc.2022.816678

DOI=10.3389/fonc.2022.816678

ISSN=2234-943X

ABSTRACT=Purpose: Tumor delineation plays a critical role in radiotherapy for hepatocellular carcinoma (HCC) patients. In this study, we evaluated a novel Multisource Adaptive MRI Fusion (MAMF) method in hepatocellular carcinoma patients for tumor delineation.

Methods: Ten patients with HCC were included in this study retrospectively. Contrast-enhanced T1-weighted MRI at portal-venous phase (T1WPP), contrast-enhanced T1-weighted MRI at 19-min delayed phase (T1WDP), T2-weighted (T2W), and diffusion-weighted MRI (DWI) were acquired on a 3T MRI scanner and imported to an in-house developed MAMF software to generate synthetic MR fusion images. Original multi-contrast MR image sets were registered to planning CT by deformable image registration (DIR) using MIM. Four observers independently delineated GTVs on planning CT, four original MR image sets, and fused MRI for all patients. Tumor contrast-to-noise ratio (CNR) and Dice similarity coefficient (DSC) of the delineated GTVs between each observer and a reference observer were measured on the six image sets. Inter-observer and inter-patient mean, standard deviation (SD), and coefficient of variation (CV) of the DSC were evaluated. 

Results: Fused MRI showed the highest tumor CNR compared to planning CT and original MR sets in the ten patients. The mean ± SD tumor CNR were 0.72 ± 0.73, 3.66 ± 2.96, 4.13 ± 3.98, 4.10 ± 3.17, 5.25 ± 2.44, and 9.82 ± 4.19 for CT, T1WPP, T2W, DWI, T1WDP, and fused MRI, respectively. Fused MRI has the lowest inter-observer and inter-patient variations compared to original MR sets and planning CT set. For the 10 patients, the mean DSC ± SD were 0.81 ± 0.09, 0.85 ± 0.08, 0.88 ± 0.04, 0.89 ± 0.08, 0.90 ± 0.04 and 0.95 ± 0.02 for GTV-PLCT, GTV-T1WPP, GTV-T2W, GTV-DWI, GTV-T1WDP, and GTV-Fused MR. The patient mean inter-observer CV of DSC were 3.3%, 3.2%, 1.7%, 2.6%, 1.5% and 0.9% for GTV-PLCT, GTV-T1WPP, GTV-T2W, GTV-DWI, GTV-T1WDP, and GTV-Fused MR, respectively. 

Conclusion: The MAMF fused MRI showed potential in enhancing tumor CNR and inter-observer consistency of GTV delineation in HCC. The MAMF method holds great promise in MRI applications in HCC radiotherapy treatment planning.