Postmastoidectomy effusion measurement using a delay-line ultrasound transducer: cadaver experiments

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.