I am after quantifying the blue stained collagen in a Masson's-Trichrome stained skin section from an immune deficient mice and compared the same with its WT control. I am curious to know can ImageJ software be used for this purpose !!
I think it depends on the nature of the structure. There is a paper:
http://www.ijcem.com/files/ijcem0059973.pdf
Incidentally, I had a similar research issue arise where I wanted to quantify the amount of collagen deposition. One of the interesting findings was the presence of abundant mast cells around the collagen lesions; they can contribute to the collagen deposition by fibroblasts as can M2 macrophage. You can stain for them using a modified quick dif staining protocol. Let me know if you would like to know how to do this quick stain procedure.