An MRI is typically done at an outpatient basis and typically takes about 45 minutes. Some doctors will order an MRI arthrogram. An arthrogram involves and injection of dye into the shoulder joint just prior to having an MRI. Although it’s a little more invasive, it typically does give a little more information. An ultrasound is a new imaging technique that is being used more and more commonly in the office to aid in the diagnosis of rotator cuff tears. An ultrasound is a portable machine where a probe can be put on the shoulder and utilize essentially no radiation at all. The ultrasound uses sound waves to image the rotator cuff muscle and will allow for the diagnosis of tear as well. The benefits of an ultrasound is that it can be performed usually onsite in the doctor’s office and allow for an immediate diagnosis. Unfortunately, you typically don’t get as much information from an ultrasound as an MRI.