Figure 4 :(a,b) Left vertebral angiogram (AP and lateral view, May 2007): Pre-embolization angiogram of the right occipital arteriovenous malformation, supplied by right parietoccipital artery and calcarine artery; (c,d): Post-embolization angiogram (May 2007) with Glubran 2, blood flow of the CAVM decreased obviously, which could make it safer for the surgery