MRA

In brief: MRA is a noninvasive angiographic technique used to view major intracranial arteries and some collateral networks.

Time-of-flight MRA is commonly obtained with brain MRI and does not require injected contrast.

Use in moyamoya disease

In moyamoya disease, MRA can show terminal internal carotid narrowing, reduced signal in proximal middle or anterior cerebral arteries, and abnormal basal or periventricular vessels.

Under defined conditions, MRI and MRA findings can support diagnosis without catheter angiography. Catheter angiography remains important when anatomy is uncertain, disease is unilateral, atherosclerosis is a concern, or detailed surgical planning is needed. [1]

Clinical detail

Slow or complex flow can cause signal loss that exaggerates apparent narrowing. MRA is therefore interpreted with source images, MRI, and sometimes DSA.