The carotid body is a tiny chemoreceptor organ located at the carotid bifurcation that senses the levels of oxygen, carbon dioxide, and pH in the blood. When it detects low oxygen levels, it sends signals to the brain to increase breathing rate and heart rate. While the normal carotid body is too small to be seen on ultrasound, tumors of the carotid body, called paragangliomas or chemodectomas, can grow large enough to be detected as a hypervascular mass at the carotid bifurcation that splays apart the internal and external carotid arteries. These tumors are an important, though rare, finding during carotid ultrasound examinations.
Sonography Term