1. In short, never. MRA, specifically, is not superior to CTA for determining if there is abnormal vascular anatomy as a cause of a spontaneous ICH. 2. However, the use of MR imaging can be very useful. In general, I recommend waiting 8-12 weeks to allow the blood to clear so that an underlying les...

I would add that the new AHA ICH guidelines include more specific criteria for when to consider angiogram even if CTA is negative, including in those younger than 45 as well as those 45-70 with no history of hypertension for example. Read more here: Greenberg et al., PMID 35579034.

Usually, if there is a good quality CTA, there is no need for repeat non-invasive vascular imaging like MRA. If the patient is young and the bleeding is not classical for hypertensive bleed, we start with an MRI brain with and without contrast in the acute setting as well as repeat it later on afte...