Fig. 2From: Giant cell arteritis presenting as bilateral anterior ischemic optic neuropathy: a biopsy-proven case report in Chinese patientThe color duplex ultrasonography showing the right superficial temporal artery of the patient: (a): the accelerating of the blood flow indicate the narrowing of the vessel; (b): the inflammation of the vessel wall as a hypo-echoic concentric ring, which referred as the “halo sign”. The blue arrow indicates the thickening vessel wall; the red arrow indicates the narrowed luminalBack to article page