My doctor thinks I may have a condition called thoracic outlet syndrome. Is it possible to find out for sure? Would an X-ray or MRI show anything?
They are called provocative tests because they put your body in a position to stretch or compress the neurovascular bundle (nerves and blood vessels). The result is a reproduction of your symptoms.
You may have turned your head toward the painful side while the doctor took your pulse. The test is positive for TOS if your pulse disappeared after you turned your head. Another test is to raise your arms overhead for three minutes while opening and closing your hands. This test is positive for TOS if your symptoms start or get worse.
An X-ray might be helpful. It can show if there are any anatomic changes such as an extra rib or bony projections that are longer than normal causing problems. Anything that can put pressure on the blood vessels or the nerves can contribute to TOS.
MRIs are actually a good tool. They can show all of the anatomic changes in both the bones and soft tissues. For example, fibrous bands of tissue across the nerves often present at birth have been identified as part of the problem.
But you may not really need an MRI. Studies show that the clinical provocative tests are good indicators that TOS is the source of your symptoms. And the treatment is diagnostic because if your symptoms go away after treatment, you know it was TOS.
It's nice to know the particulars behind the problem. Knowing there are fibrous bands of tissue or cervical ribs can help the physical therapist treating you. But the tests are expensive and the provocative tests may be enough to make the diagnosis.
Derya Demirbag, MD. The Relationship Between Magnetic Resonance Imaging Findings and Postural Maneuver and Physical Examination Tests in Patients with Thoracic Outlet Syndrome: Results of a Double-Blind, Controlled Study. In Archives of Physical Medicine and Rehabiliation. July 2007. Vol. 88. No. 7. Pp. 844-851.