WE-FG-202-10: Assessing Hepatocellular Carcinoma (HCC) Response to SBRT Using DCE-MRI

Authors


Abstract

Purpose:

To investigate the feasibility of using DCE-MRI to assess treatment response of HCC to SBRT.

Methods:

For seven liver HCC patients treated by photon SBRT with radiation dose ranging from 35 to 50 Gy in 5 fractions, T1-weighted DCE-MRI was performed before and at 1–3 months after the treatment. Each study included one pre-contrast and five post Gd-EOB-DTPA-enhanced imaging series. The target tumor and the liver were manually outlined on the arterial phase images. Then, a regional deformable image registration was applied to align liver volumes at different phases in order to compensate respiratory and cardiac motions. An unsupervised fuzzy c-means clustering technique was carried out to partition the tumor voxels into a number of groups based on their enhancement patterns over time. The representative kinetic curve of the tumor was selected as the one with the maximum enhancement. Six semi-quantitative features were extracted to depict the maximum contrast enhancement, uptake rate, washout rate, time to peak, the area under the kinetic curve (AUKC), as well as the ratio of the most enhanced area in each tumor. The change of these feature values after SBRT was compared using Wann-Whiteney test to characterize the tumor response to RT.

Results:

Eight HCCs from these seven patients were included in this retrospective study, in which four were identified to respond well to SBRT. The responding tumors showed reduced enhancement after SBRT while the non-responding tumors had steady or even enhanced kinetic dynamics. The median AUKC change after SBRT was −0.65 for responding tumors and 1.0165 for non-responding tumors (p=0.029)

Conclusion:

The preliminary results demonstrate that DCE-MRI has the potential to monitor the effects of SBRT in patients with HCC. We are expanding our database and developing more quantitative imaging biomarkers in the future study.

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