Mechanism of Cerebral Aneurysm Bruits: Resonance of Parent Artery and Aneurysm

Cerebral aneurysms have distinct sounds that peak at a frequency between 260–660Hz, very different from the spectrum without aneurysms [1]. While this phenomenon has been known for years, the exact cause of bruits is not known. Figure 1 shows the spectrums of sounds from a healthy subject and a 65-year-old patient with a 16mm aneurysm at the paraclinoid segment of the internal carotid artery using a digital electronic stethoscope. The healthy subject has a peak at 96Hz, and the spectrum for the aneurysm patient peaks at 403 Hz.