I'd believe the PT

I have found that good PTs & good chiros understand more about the whole in depth workings of the body than most Drs.

I've always read that it is more of a ruling out tool than actual diagnosing tool.

[Patients with other neurological conditions, (e.g., CTS or cervical disk disease) may develop various symptoms as a result of individual provocative maneuvers but the patterns are markedly different than those for thoracic outlet syndrome. It is not clear whether the severity of TOS is indicated by how long the patient can tolerate the test. The symptoms which the patient describes following the EAST maneuver are strong indicators for the presence of TOS.
Other Diagnostic Tests

A variety of other diagnostic tests may be used in assessing patients with signs and symptoms of TOS. None of these tests are specific for TOS but are used primarily to rule-out other possible causes of the signs and symptoms that the patient is experiencing. Testing should be done selectively based on the patient's history and physical exam. The tests may include:]

read more here -
http://www.medifocushealth.com/RT017...-Syndrome3.php

the next page on that site talks about dx Vascular TOS

hmmm- Pec minor syndrome isn't mentioned but the site has some good info - I haven't tracked any of these down for quite awhile - I suppose some of the main ones have been updated. the links in the stickys should go to the updated info as long as the site has the same web ID.