Acoustic reflectometry imaging of the airway

This review deals with time-domain acoustic reflectometry, which is a dynamic, real-time imaging modality that can be used to generate an easily interpretable area-distance profile of a cavity, such as the breathing tube/lower airway system or the esophagus. Without resorting to capnography, the acoustic reflectometry profile allows for instant diagnosis of the site of placement of the breathing tube: tracheal, bronchial, or esophageal. Additional applications include: evaluation of sleep apnea, septal disorders, plus the site and the severity of breathing tube obstruction (kinks, mucus plugs) and of lower airway abnormalities (bronchospasm, pulmonary edema). Other applications of the acoustic reflectometer are discussed.