Torn rotator cuff tendon shows on ultrasound but not mri. what does this mean?

Tough question: Depends on the skill of the ultrasonographer/reader of the mri, extent of tear, location of tear, and whether the MRI was done using contrast injected into the joint. These factors need to be taken into account with your clinical evaluation. Overall, an MRI with contrast injected in the joint is the exam which most reliably provides information in most parts of the usa.

I would consider: Seeing a shoulder specialist and bringing the two studies to him or her. Radiologists can interpret things differently based on the quality of the study and on their experience. Contact a shoulder surgeon. Often they are interested in reviewing films for folks. I do.