Assessment of changes in perfusion after radiotherapy for brain metastasis using three-dimensional arterial spin labeling / 中国肿瘤临床

ABSTRACT

Objective: This study aimed to quantitatively analyze changes in blood perfusion in brain metastases (BMs), normal brain areas, and peritumor edema areas during radiotherapy (RT) using three-dimensional arterial spin labeling (3D-ASL) in BMs patients. The associations between perfusion changes in the three brain regions and RT dose gradients need to be established to provide a reference for individualized RT for BMs patients. Methods: MR-simulated location images of 26 BMs patients before and after RT were collected (including enhanced T1W images and perfusion maps of 3D-ASL; BMs tumor target areas were identified using enhanced T1W images and perfusion information was obtained from 3D-ASL). The high signal areas of BMs on contrast-enhanced T1W images, normal brain areas, and peritumor edema areas were defined as regions of interest (ROIs). The changes and correlation of the mean maximum cross-sectional area and mean maximum cerebral blood flow (CBF) in BMs tumor target areas before and after RT were assessed. Changes in CBF values in the three ROIs under different dose gradients were analyzed. Results: The mean maximum cross-sectional area and CBF values of BMs decreased by 26.46% and 29.64%, respectively, after RT (both P50 Gy dose gradients were 33.75%, 24.61%, and 27.55%, respectively (all P50 Gy, the decreasing CBF rates after RT were 7.65%, 11.12%, 18.42%, 20.23%, 19.79%, and 17.89%, respectively (all P<0.05). The decreasing CBF rates in peritumor edema areas increased as dose gradients increased after RT. The perfusion changes in BMs after RT were more notable than those in normal brain areas and peritumor edema areas. Conclusions: Thus, 3D-ASL can objectively reflect changes in perfusion in BMs, normal brain areas, and peritumor edema areas. Based on changes in CBF, it is recommended to control the dose administered to normal brain areas to <30 Gy, whereas high doses