Marrow edema is excess collection of fluid that usually occurs in response to infection, inflammation or injury. Thus it is seen in fractures, ligament injuries, bone bruises (injury to bone without a fracture), synovitis (inflammation of the synovial membrane that lines the joints), osteoarthritis, osteoporosis, ischemia (decreased blood flow) and tumors. In your case it is most likely to be due to osteoarthritis, synovitis or ligament tear.
“Rim rent tear of the supraspinatus” is basically a tear in the rotator cuff of the shoulder. In your case this tendon has a partial tear. This will respond to physiotherapy and non steroidal anti-inflammatory. Take care!
The medical advice given should not be considered a substitute for medical care provided by a doctor who can examine you. The advice may not be completely correct for you as the doctor cannot examine you and does not know your complete medical history. Hence this reply to your post should only be considered as a guiding line and you must consult your doctor at the earliest for your medical problem.