Postmastoidectomy Effusion Measurement Using a Delay-Line Ultrasound Transducer

Abstract

Mastoidectomy is a surgical procedure for removing mastoid air cells and has been used widely to establish drainage and cleaning infections from the mastoid bone. Computed tomography (CT) and magnetic resonance imaging (MRI) are the primary instruments used to clinically detect mastoid effusion following surgery. This study examines the feasibility of ultrasonography to detect postsurgical mastoid effusion. In vitro ultrasound measurements were conducted on 10 cadavers. For each sample, mastoidectomy was performed, and saline and whole blood samples were injected into the surgical mastoid cavity to simulate different effusion properties. A 2.25-MHz delay-line ultrasound transducer was used to obtain ultrasound backscattered data from the mastoid. The data were used to analyze echo intensity and the backscattered statistics by estimating the scaling and Nakagami parameters of the Nakagami distribution model. The results show that the scaling and Nakagami parameters can successfully detect mastoid effusion. Specifically, the Nakagami parameter is capable of characterizing the mastoid effusion properties. This indicates that ultrasound measurement based on a combination of delay-line transducer and Nakagami parameter estimation is a potential real-time diagnostic tool for evaluating mastoid effusion following mastoidectomy without radiation exposure.

Ultrasound characterization of the mastoid for detecting middle ear effusion: A preliminary clinical validation

“…The transducer was driven by a high-voltage excitation signal generated from a pulser and thus the excitation signal and backscattered echo from the mastoid may overlap during data acquisition, complicating the observation of the behaviors of the backscattered signals from the mastoid air cells. Under this condition, a delay-line transducer is highly suitable for mastoid measurements 42 . Delay-line transducers are of a single-element type, specifically designed to incorporate a short piece of plastic or epoxy material in front of the transducer surface.…”