 Brain AVMs may be detected on computed tomography angiography ( CTA or CT angio ) or magnetic resonance angiography ( MRA ) ; CTA is better in showing the vessels themselves , and MRA provides more detail about the relationship between an AVM and surrounding brain tissue . In general , MRI is recommended . Various types of vascular malformations may be encountered : AVMs , micro @-@ AVMs , telangiectasias and arteriovenous fistulas . If surgery , embolization , or other treatment is contemplated ( see below ) , cerebral angiography may be required to get sufficient detail of the vessels . This procedure carries a small risk of stroke ( 0 @.@ 5 % ) and is therefore limited to specific circumstances . Recent professional guidelines recommend that all children with suspected or definite HHT undergo a brain MRI early in life to identify AVMs that can cause major complications . Others suggest that screening for cerebral AVMs is probably unnecessary in those who are not experiencing any neurological symptoms , because most lesions discovered on screening scans would not require treatment , creating undesirable conundrums . 
