The effect of time-delayed contrast-enhanced T2-FLAIR on the visualization of large-volume brain metastases

Motivation: Combining CE T2-FLAIR with CE T1WI increased the detection rate of BMs compared to using CE T1WI alone. Goal(s): We aimed to provide a basis for improving the BMs GTV determination in shorter time. Approach: Three radiotherapists delineated the tumor on the CE T1WI and CE T2-FLAIR images. ROI-1min, ROI-3min and ROI-5min were fused with ROI-T2-FLAIR in varying combinations. The ROIs volume, DSC, HD, and the SIs of the ROIs were calculated. Results: The volumes of the fusion ROIs all were slightly increased compared with that of ROI-total, and the fusion ROIs had a DSC range of 0.903-0.917. Impact: Our results show that combining time-delayed CE T2-FLAIR and CE T1WI enhances BM visualization and GTV segmentation accuracy, allowing quantitative analysis of BM imaging differences in various sequences through GTV volume and shape evaluation.