Both CT angiography and conventional angiography have their own pros and cons.
CT Angiography is an imaging procedure and hence complication related to invasive procedures is always less.
If the patient's condition is stable then he may choose to go for CT Angio than a traditional surgical procedure.
Compared to this Conventional Angiography is one of the best ways to diagnose artery disease by providing a detailed X-ray.
Also In case a patient has blockages and requires the next stenting procedure, it can be done in the same sitting no separate visit is required. Most doctors prefer and advise patients to get the stenting done after the Angiogram if the blockage is found and the same can be treated by stenting.
overall the resolution in traditional invasive Angiography is always better than CT Angiography