Original
A doctor may suspect an AVM as the culprit for brain issues such as a hemorrhage or other similar problem but the only way to tell for sure is through an Angiogram/Angioplasty or an MRI (usually an MRI with contrast).
Angioplasty uses a catheter input to the Femoral Artery. A dye is shot into the area to see blood flow and can spot the telltale cluster of an AVM.