I hurt my right shoulder in a skiing accident. I've had an X-ray and an MRI without finding anything. The doctor thinks I tore the rim around the shoulder socket and wants to do one more test called an arthrography. What's this test going to do that the other tests couldn't?

Magnetic resonance arthrography (MRA) uses an injected dye and special X-ray called fluoroscopy to find labral (cartilage) and ligament tears. The dye seeps into any openings, cracks, or tears that shouldn't be there.

MRA is a sensitive and reliable test. That means it correctly shows a labral tear when there is one. Studies show MRA is most accurate finding anterior tears (95 per cent) sensitivity. Ligamentous tears above or below the shoulder are less sensitive).

Arthroscopic exam is equally effective in making this diagnosis. The advantage of arthroscopy is the ability of the surgeon to go ahead and repair the tear immediately. The disadvantage of arthroscopic exam is that it requires surgery. MRA does not require anesthesia, any punctures, or open incisions of the shoulder.