Figure 1. Pipeline for BBB opening volume quantification and drug delivery analysis based on MR image processing.

(A) To quantify BBB opening volume, the contrast enhancement map (upper: horizontal slice, lower: coronal slice) were used after dividing the post-Gd T₁ images by the pre-Gd images. Then, after applying the brain mask and the vessel mask in order to filter out the contrast enhancement outside of the BBB opening area (B), the opening volume was calculated by subtracting the VOI in the contralateral area (dashed rectangle) from the targeted area (solid rectangle) (C). On the other hand, the pre- Gd T_1,0 (D) and post-Gd T₁ maps (E) were used to quantify the amount of Gd delivered and its delivery efficiency since the Gd shorted the T1 time after diffused the BBB opening region (arrowhead). The Gd concentration map (F) (upper: horizontal slice, lower: coronal slice) was acquired by calculating the change of T₁ time between pre- and post-Gd T₁ maps. After applying the brain mask and excluding the Gd retention in the vessels by thresholding (G), the amount of Gd delivered was calculated by subtracting the VOI in the contralateral area (dashed rectangle) from the targeting area (solid rectangle) (H).