The preangiographic diagnosis of cerebral dural arteriovenous fistula (DAVF) can be difficult. The magnetic resonance (MR) images of 12 patients with angiographically proved DAVF were evaluated to characterize the appearance of these lesions and to identify those patients at increased risk for complications. Patients with DAVF demonstrating venous occlusive disease are at higher risk for complications from the arterialized collateral venous system. This venous occlusive disease is demonstrated best at arteriography. The MR imaging appearance of dilated cortical veins without a parenchymal nidus is suggestive of a DAVF with veno-occlusive disease. Eight of the 12 patients in our series demonstrated this finding at angiography. Complications, including infarction and hemorrhage, were identified at MR imaging in eight patients with MR imaging evidence of veno-occlusive disease. At angiography 42% of these complications were not apparent. In one patient with a DAVF draining into an unobstructed right sigmoid sinus, results of MR study were normal. Although patients with DAVF without veno-occlusive disease may have normal findings at MR imaging, DAVF associated with veno-occlusive disease and dilated pial venous drainage can be documented on MR images. This subset of DAVF patients, many of whom were identified only at MR imaging, is at higher risk for complications due to veno-occlusive disease. These patients are believed to require more urgent therapy. MR imaging is useful in the pretherapeutic planning for patients with DAVF.

Treatment of complex intracranial aneurysms by means of interventional neurovascular techniques is now being performed with a newly developed silicone detachable-microballoon device. The balloon is composed of unique silicone elastomers that are extremely soft and malleable. It therefore conforms to the blood vessel lumen or aneurysm wall and reduces the risk of rupture. It is affixed onto a 2.0-F catheter and can be either directed by flow or guided with the catheter. For aneurysms with a well-defined neck, the balloon is placed directly into the aneurysm, inflated with 2-hydroxyethyl methacrylate for permanent solidification, and detached. The aneurysm is thus excluded from the circulation, and the parent vessel is preserved. For aneurysms without a well-defined neck, test occlusion can be performed, followed by permanent balloon occlusion of the parent vessel. This balloon technique has been successfully used to treat aneurysms in both the anterior and posterior circulations, where standard neurosurgical techniques have failed, and in surgically inaccessible anatomic locations.