I-Corps: Intracranial Phonocatheter to Enable Diagnosis of Pulsatile Tinnitus

University Of California-San Francisco, San Francisco CA

Investigators

Abstract

The broader impact/commercial potential of this I-Corps project is the development of a medical device capable of diagnosing Pulsatile Tinnitus (PT) by measuring hemodynamic changes within the brain’s venous outflow tract. Currently, PT evaluation takes 4 - 6 hours and consists of diagnostic cerebral angiography, diagnostic cerebral venography, venous manometry, and balloon occlusion tests all performed essentially without any sedation to provide operators with the best guess of where the sound is originating. Rather than relying on patients to relay to the physician their experience, the proposed device is designed to directly measure pressure fluctuations causing sound and provide a map of sound overlying the patient’s vasculature that physicians will interpret. The proposed technology may obviate painful balloon occlusion tests and venous manometry and shorten procedural time to a more reasonable 30 minutes. Over 3 million Americans are estimated to have PT, and 65% of them suffer from debilitating depression, anxiety, or both. A reliable diagnosis may allow neurointerventional physicians to treat their symptoms and improve outcomes. This I-Corps project is based on the development of a diagnostic microcatheter medical device to diagnose Pulsatile Tinnitus (PT). The proposed device is designed with one or more embedded transducers that can convert the pressure fluctuations of sound generated in blood vessels into electrical signals and provide a map of sound generation directly to the neuroendovascular surgeon in real-time with both visual and audible feedback. Analogous to electrophysiology mapping of the heart, the proposed technology provides physicians with an objective map of pressure waves (correlating to sound production) within the vasculature and enables the diagnosis. Proof of concept has been evaluated using a prototype system with an off-the-shelf microphone chip embedded at its distal tip that is able to directly detect PT sounds using benchtop flow models derived from patient-specific magnetic resonance imaging (MRI) data before and after treatments. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.