Hypoplastic vertebral and basilar arteries definition help?

I am a 27 y/o female with a 5 year history of complicated migraines coupled with persistent numbness and tingling of my hands/feet and generalized weakness of my hands to where its hard to grip and open items like jars or bottles.

I recently had a brain MRI w/wo contrast. Everything was normal except for this line. My MRI was compared to a cervical spine MRI that was normal except for a bulging disc at C4-5 - What does this mean:

Report
The proximal cerebral arteries and saggital sinus are patent. The distal vertebral arteries and basilar artery are hypoplastic. The posterior communicating arteries are seen in the suprasellar cisterns.

Impression
Normal MRI of the brain. Suspect persistent fetal circulation of the posterior cerebral arteries about the circle of Willis with hypoplastic distal vertebral and basilar arteries.

I guess the next step is an angiogram, what will that tell me? Thanks