I spent two summers working in the international services department of a major American medical school, helping with visa applications for foreign medical stud

I spent two summers working in the international services department of a major American medical school, helping with visa applications for foreign medical students and doctors. I can tell you that we had Iranian nationals studying there. (Yes, I know, not Arab). It's certainly not impossible; other posters are right that the biggest barriers are cost, US immigration services' incompetence, and slow response time to applications.