Assessing the Relationship Between MR-Based Functional Dose Metrics and Post-Stereotactic Body Radiation Therapy...

This study aimed to identify predictors of global liver function change measured by albumin-bilirubin (ALBI) score following stereotactic body radiation therapy (SBRT) in patients with hepatocellular carcinoma (HCC). By integrating gadoxetic acid-enhanced magnetic resonance imaging (MRI) uptake and dosimetric data, the goal was to develop functional-based treatment-planning strategies that preserve hepatic function.

Twenty-five patients with HCC enrolled on an institutional review board-approved adaptive SBRT trial had liver dynamic gadoxetic acid-enhanced MRI and blood sample collections before and 1 month after SBRT. Gadoxetic acid uptake rate (k1) maps were quantified for regional hepatic function and coregistered to both 2-Gy equivalent dose and physical dose distributions. Mean or integral-based metrics, dose-volume or function-volume histogram metrics, and function-dose-volume histogram metrics were calculated. These metrics were correlated with percentage ALBI score changes by Spearman rank correlation with Bonferroni correction.

We found that the greater the sparing of liver with high-hepatic function (k1 intensity), the less the decline of ALBI score post-RT. The threshold for preserving global hepatic function was 10 % of the maximum k1 intensity and 5 Gy EQD2. The integration of regional function (k1) and dosimetric data improved the ability to predict ALBI score changes compared with dosimetric or functional data alone.

Combining regional liver function metrics from gadoxetic acid-enhanced MRI with radiation dose provides a robust model for predicting ALBI score changes following SBRT. These findings suggest that there is a potential for functional-based treatment planning to better preserve liver function in patients with HCC undergoing SBRT. Future studies are needed to externally validate these findings.