Axial MRA 3-D reformatted image of the brain. Axial MRA 3-D reformatted image visualizes the intracranial arterial system. Right ICA appears attenuated in caliber (red arrows) involving its cavernous, clinoid, and supraclinoid segments. Subtle marginal irregularities (white arrow) are also noted in bilateral MCA and ACA. The right posterior communicating artery appears hypo-plastic (normal anatomical variant).ICA - internal carotid artery; MCA - middle cerebral artery; ACA - anterior cerebral artery