Using ImageJ for staining analysis

[melbecke]

Hello,
       I am a new user of the Image J software and have a question on the
application I am looking for.
The thing is, that we stained lipids in mouse aortas with SudanIV. Now im looking for a software that can
measure the size of the red plaques by counting all red pixels, compared to the size of the total aorta.
Does anybody know if there is an ImageJ Plugin I can use for that application?

It would be great if anyone knows what I mean and can help me to find the right program

Thanks in advance

Melanie Becker