Vigen T, Ihle-Hansen H, Lyngbakken MN et al. - Because the pulsatility index (PI) in the middle cerebral artery (MCA) is considered a measure of peripheral vascular resistance, researchers determined whether ultrasound-derived indices of carotid atherosclerosis are associated with MCA PI. Of the 3,706 participants enrolled, 3,154 candidates had adequate transcranial and carotid data. Mean MCA PI was 0.97. The authors discovered that participants in MCA PI's upper quartile had higher pulse pressure, hypertension more often, diabetes mellitus, and a history of coronary artery disease. Overall, ultrasound-derived indices of carotid atherosclerosis were independently linked to MCA PI in a population-based sample of middle-aged adults. MCA PI variation, however, was small, indicating that factors other than atherosclerosis and cardiovascular risk factors may play a significant role in MCA PI.