Carotid artery stenosis a physician detects a carotid bruit, or murmur, over the carotid artery by listening through a stethoscope during a physical exam. For people with symptoms, the American Heart Association recommends initial screening using ultrasound (see diagnosis below). Carotid artery stenosis is usually diagnosed by color flow duplex ultrasound scan of the carotid arteries in the neck. This involves no radiation, no needles and no contrast agents that may cause allergic reactions. This test has good sensitivity and specificity. Typically duplex ultrasound scan is the only investigation required for decision making in carotid stenosis as it is widely available and rapidly
Carotid body may involve mitochondrial oxygen sensors and the haem-containing cytochromes that undergo reversible one-electron reduction during oxidative-phosphorylation. Haem reversibly binds O with an affinity similar to that of the carotid body, suggesting that haem containing proteins may have a role in O, potentially this could be one of the complexes involved in oxidative-phosphorylation. This leads to increases in reactive oxygen species and rises in intracellular Ca. However, whether hypoxia leads to an increase or decrease in reactive oxygen species is unknown. The role of reactive oxygen species in hypoxia sensing is also under question. The oxygen dependent enzyme haem-oxidase has also