Noninvasive Bolus Transit Detection in Cervical Esophagus Utilizing Ultrasound Characteristics

This pilot study aims to identify characteristic A-mode ultrasound features relevant to noninvasive detection of esophageal bolus transit in the proximal esophagus. Ultrasound signals at a lateral neck site were obtained via a single-element ultrasonic transducer with synchronous videofluoroscopic swallowing studies images of swallows of differing viscosities in 21 adult dysphagia outpatients. Characteristic ultrasound features were extracted to differentiate a bolus-filled from a collapsed esophagus. From 21 subjects, 412 swallows exhibited 4 reproducible waveform patterns associated with bolus transit as displayed in a heatmap: (1) Strong Reflectors; (2) Echo Shifts; (3) Distal Acoustic Enhancement; and (4) Speckling: One or more of these features were observed in the swallow series for all 21 subjects. Distinct acoustic waveform features acquired by single-element ultrasonic transducers can identify bolus transit through the cervical esophagus.