MRI Evaluation of Nidus Occlusion After Gamma Knife Radiosurgery of Cerebral Arteriovenous Malformations - A Prospective Preliminary Study

Cerebral arteriovenous malformations (AVMs) are abnormal vessels, connecting cerebral arteries and veins. They form a bundle which is called nidus. Rupture of an AVM leads to intracranial hemorrhage often causing neurological impairment or even death. As treatment can be associated with high rates of morbidity and mortality, AVMs still remain a considerable challenge for neurosurgeons. For smaller AVMs, a well-established treatment option is non-invasive Gamma Knife radiosurgery (GKRS). GKRS uses radiation to obliterate the AVM nidus hence, eliminating the risk of hemorrhage. However, after Gamma Knife radiosurgery, occlusion of the AVM nidus takes about two years. To evaluate treatment success after GKRS, invasive digital subtraction angiography (DSA) is still the gold standard. For this procedure, patients have to undergo puncture of the femoral artery for application of a contrast media to receive adequate imaging of the cerebral arteries. In recent literature it has been discussed whether sufficient evaluation of treatment is possible with non-invasive magnetic resonance imaging (MRI). At present, it is unclear whether this method could replace the current invasive gold standard for treatment evaluation. To investigate on this issue, a few studies have compared the two methods however, only retrospective data exist. Thus, the investigators are conducting this prospective study including 50 patients with cerebral AVMs treated with GRKS to evaluate the sensitivity for nidus obliteration of MRI using DSA as a reference.