Procedures of automatic ROI selection. A MIP image is first generated from all the acquired sweep scan images. After applying a median filter, the procedure selects a square region consisted of 25 × 25 pixels and uses FCM clustering to distribute pixels into 3 groups according to the signal intensity. The group with the highest averaged intensity generates a binary mask. The binary mask then underwent erosion and subsequent dilation to remove small objects and connect neighboring objects in the mask. Finally, the procedure selected an object with the center of mass closest to the center of FOV as heart ROI (indicated as yellow dots).