Blood flow noise transducer for detecting intracranial vascular deformations

Abstract

A transducer using PVDF film, which is placed on the eyelid, has been designed to measure intracranial blood flow noise, called “bruit”, as a screening test for detecting intracranial vascular deformations such as aneurysms, stenosis, and malformations. First, the mechanical impedance of the eye was measured. Then, the transducer performance on the eye was evaluated in terms of sensitivity versus frequency while varying the parameters of the transducer components. The prototype transducer fabricated had a sensitivity of −76dB(0dB=1V/(dyn/cm²)) at frequencies of up to around 1, 000Hz. It was successfully used in a neurosurgical clinic to measure the bruit signals, and was proved to be effective for detecting cerebral aneurysms and stenosis.