From the blog "Mike at Medical Models"

So I have seen some questions here on embodi3D asking how to work with MRI data.  I believe the main issue to be with attempting to segment the data using a threshold method.  The democratiz3D feature of the website simplifies the segmentation process but as far as I can tell relies on thresholding which can work somewhat well for CT scans but for MRI is almost certain to fail.  Using 3DSlicer I show the advantage of using a region growing method (FastGrowCut) vs threshold.