Stress Test False Positive or...?

Hi,
Help! My wife had a stress test recently because her family doctor just purchased stress test equipment(note: she has had no symptoms of heart problems but has diabetes). She was the 4th person to have the test on this equipment. According to the results stress images reveal a large sized perfusion abnormality of moderate to severe intensity in the lateral and anterolateral walls . Stress images also showed a medium sized perfusion abnormality of mild to moderate intensity in the interoseptal and inferiolateral walls. Grade V stage. Gated SPECT revealed abnormal left ventricular function with an ejection fraction of 36%. There was severe hypokinesis in the inferior, lateral, anterolateral, and inferolateral walls of the left ventricle. There is diminished systolic wall thickening in these regions as well. Images would appear to show that heart is not functioning while under stress.
Family doctor and specialist are recommending Standard Angiogram.
Wife and I have doubts about the validity of the test because she was the 4th patient to have it(at least 1 other patient had an abnormal reading). Also there is a percentage of false positives in females.
When we suggested a CTA doctors balked saying that she would still need a Standard Angiogram.
Are we wrong in wanting the CTA first(we would pay entire cost of test) then if indicated have the Standard Angiogram.
Thank you for reading and hopefully replying.

[remar]

I would absolutely seek a second opinion and have another stress test done by a different Dr. Don't wait long in case her current Drs machine is indeed working correctly.