Import a Photoshop selection into Matlab

Let's say I have an image that I open in Photoshop, and I make a selection of a region, for example with the lasso tool. I would like to import the x,y locations of the selected pixels into Matlab. I know you can run Photoshop from Matlab, and read and write PSD files from within Matlab, and in Photoshop you can save a selection to a (unfortunately smaller) PNG file. But I am not sure how to combine these to get the selected pixels' location into Matlab. What might work? (For this task I must do the selection in Photoshop. I am asking a narrower version of this question to the Photoshop community here, and here I ask about one approach I am trying in Matlab).