How to fill a segmented region of an image with color?

I have used the code MagicWand provided by ImageAnalyst (Huge Thanks btw!) to apply Region Growing segmentation on an image, and applied Active Contour on the result, like this:

Where imageArray is this:

With selecting a particular seed point, the image after applying Region Growing method, the outputImage looks like this:

And after applying Active Contour Method like this:

acimg=activecontour(imageArray,outputImage,iteration,'Chan-Vese');

The output looks like this:

Now, I want to fill the segmented region with white, so it looks something like this:

But I don't want a overlayed image. Can I extract a single image file (Like imageArray or outputImage so that I can use it for further operation) from it?

Thanks in advance!