Calculate mean with same ROI on multiple images

I used the function mmROI to draw three ROIs and calculate the mean value of this ROI in multiple images. Next, I corrected the orginal images and now I want to calculate the mean value again, using the same ROIs. However, I cannot get it done. I tried to use poly2mask and roipoly, but haven't found the solution yet. Below are the two things I've tried.

if true
  I = Fluo_Corrected_ExpTime(:,:,:,1);
J = imadjust(I);
BW = roipoly(X1, Y1,J,720,1080);
imshow(J)
hold on
plot(X1, Y1, 'r.-', 'MarkerSize',15);
end

if true
  I = Fluo_Corrected_ExpTime(:,:,:,2);
J = imadjust(I);
imagesc(I)
ROI1 = poly2mask (X1, Y1,720,1080); %mxn is size image
Bimg = imagesc(ROI1)
end

[Adam]

How did you calculate the mean the first time and why can't you just do the exact same thing again on the new image(s)?

[Image Analyst]

See my answer in your prior, duplicate post: http://www.mathworks.com/matlabcentral/answers/322842-use-roipoly-or-poly2mask-to-calculate-intensity#answer_252898

[Ihiertje]

@Adam: the first time I used the function mmROI in which the mean value is calculated. However, I want to use the ROI defined in this function to use in other images. Therefore, I cannot do it the same way.

[Adam]

I've never heard of a function called mmROI so I don't really know what that does.