I am not sure exactly what you are asking. I think all strokes that follow a cerebral angiogram should be included in the overall risk. This risk varies based on the overall risk of the population you are performing the procedure in. Also on whether an intervention was performed, and where the intervention was performed and on whether or not there was complete occlusion of the vessel or not, and on the presence of collaterals. Positive brain scans in the absence of symptoms are hard to validate so that is why they are not performed routinely.