In addition to a MRI scan AVMs need to be evaluated by cerebral angiography. This will give important information regarding the structure of the AVM, and what vessels contribute to it. AVMs are graded by the Spetzler-Martin grading system. This system uses three important characteristic of the AVM to arrive at the grade. The higher the grade of an AVM the more difficult it is to treat it, and the higher the risks associated with them.
Surgery is considered the treatment of choice in most AVMs.
The role of surgery in the clinical management of a given patient is based on a composite of the probable natural history of the patient's future clinical course, the risk of surgical management, and the patient's age. The drawback is that the risks of hemorrhage are not decreased until approximately 2 years after the treatment. However, this method does not have the risks of open surgery, such as bleeding and damage to critical structures. The optimal treatment method needs to be determined by careful evaluation of the patient and the diagnostic studies that are available. Based on the patients expectations and needs and the grade of the AVM the optimal treatment modality can be formulated.