There is no trace on the web regarding the AngioImage application. Also, when you talk about the license, it usually means that's saved in different ways: using a license file, a serial number, of online activation. Apart from the first two, the latest one requires you connect to an online server to activate the application. Check your email that you use to purchase the license key because what you need might be there.
Another problem appears if you find the license key: the availability of the setup package. It appears there is no information on how to download the software.