MRI of the rotator cuff how to differentiate tendinosis. Its all about the signal on the PDFS. Tendinosis is high signal but not fluid signal like a tear. When there is loss of fibres from tearing, that space fills with fluid, so the signal at the site of the tear is fluid signal.
Image Above: PD and PDFS demonstrates increased signal in the supraspinatus tendon ( blue arrow) but not fluid signal. This is in keeping with tendinosis.
Image above: Bursal surface tear of supraspinatus is much brighter fluid type signal in the left image. On the right side image there is tear with loss of volume of the SST compared to the more proximal tendon.