Abstract
The macaroni sign of Takayasu’s arteritis and the hypoechoic halo sign of giant cell arteritis are characteristic signs of vasculitis on ultrasonographic images of the head and neck region. The macaroni sign is found in the common carotid artery, and the hypoechoic halo sign is found in the superficial temporal arteries. With both types of arteritis, inflammation of the large blood vessels causes various symptoms. On the other hand, some cases are diagnosed based on abnormal findings on carotid ultrasonography. The ultrasonographic findings in Takayasu’s arteritis include low-intensity lesions around the blood vessels, intima-media complex (IMC) thickening, adventitial ambiguity, constriction, and occlusion. The hypoechoic halo sign seen in giant cell arteritis is due to the presence of low luminance surrounding the circumference of the blood vessel. In addition, various other features, such as thickening of the IMC, expansion/meandering, aneurysm formation, and narrowing/occlusion of the lumen, are recognized.
