Hypervascular tumor. Hypervascular tumor. Right carotid artery angiogram shows displacement of the branches of the middle cerebral artery. The tumor blush is indicated by the arrows.fig 2. Hypovascular tumor. Right carotid artery angiogram shows no tumor blush. The mass effect exerted by the tumor causes displacement of the insular branches of the middle cerebral artery as they enter the Sylvian triangle Kira L. Chow et al. AJNR Am J Neuroradiol 2000;21:471-478 ©2000 by American Society of Neuroradiology