title: Using 1 MHz pulse-echo ultrasound externally applied to detect mastoid effusion: cadaver experiments.
abstract: The objective of this study is to explore the feasibility of using ultrasound to detect mastoid effusion (ME). In the past, ultrasound has been used to measure middle ear effusion (MEE) by injecting water into the external ear canal to measure echoes from the tympanic membrane, which is uncomfortable for the patient. It has been shown that air cells in the mastoid of patients with MEE are filled with fluid, which implies that ME could be a useful indicator of MEE. This study suggests using ultrasound to detect ME as a potentially noninvasive approach for MEE detection. In vitro experiments were performed on ten cadaver samples of the human ear. A single-element 1 MHz transducer was used to measure the mastoid of each cadaver before and after injecting water into the mastoid. The experimental results showed that the relative amplitudes of ultrasonic signals differed significantly between before (0.24 ± 0.09, mean ± standard deviation) and after (0.15 ± 0.03) the water injection (p<0.05, t-test), demonstrating that the ultrasonic reflection can be used to detect ME. The location of the human mastoid under the skin behind the ear allows external measurements, and hence ultrasound-based ME detection may be an alternative, noninvasive diagnostic approach to detecting MEE in the future, providing an examination that avoids discomfort.
authors.affiliation: Department of Otolaryngology - Head and Neck Surgery, Chang Gung Memorial Hospital, Chang Gung University, Taoyuan, Taiwan.
authors.forename: Chin-Kuo
authors.initials: CK
authors.lastname: Chen
authors.forename: Yung-Liang
authors.initials: YL
authors.lastname: Wan
authors.forename: Po-Hsiang
authors.initials: PH
authors.lastname: Tsui
authors.forename: Wen-Ta
authors.initials: WT
authors.lastname: Chiu
authors.forename: Fang
authors.initials: F
authors.lastname: Jui
mesh_terms: D002102:Cadaver; D004867:Equipment Design; D005240:Feasibility Studies; D006801:Humans; D008416:Mastoid / Q000000981:diagnostic imaging*; D010034:Otitis Media with Effusion / Q000000981:diagnostic imaging*; D014159:Transducers; D014463:Ultrasonography; D014867:Water
chemical_list: D014867:Water