Establishing a Methodology for Ultrasound Evaluation of Pharyngeal Residue in the Pyriform Sinus and Epiglottic Vallecula

Background: Assessing the presence of pharyngeal residue in the pyriform sinus and epiglottic vallecula is important because insufficient pharyngeal clearance is a risk factor for aspiration pneumonia. Improvements in the performance of ultrasound to visualize the pyriform sinus and epiglottic vallecula are needed. The aim of this study was to establish a method to visualize the pyriform sinus and epiglottic vallecula with ultrasound to detect pharyngeal residue.

Methods: We used real-time virtual sonography (ie, a fusion of magnetic resonance imaging and ultrasound imaging) as the scanning method to visualize the pyriform sinus and epiglottic vallecula without residue in 4 healthy individuals. Using established ultrasound methodology and fiberoptic endoscopic evaluation of swallowing, 35 subjects with dysphagia were studied to investigate the performance of ultrasound to detect pharyngeal residue.

Results: The fusion ultrasound images showed that transverse scans at the level of the laryngeal prominence and above the hyoid bone using a linear array transducer can be used to visualize the pyriform sinus and the epiglottic vallecula, respectively. We obtained 238 ultrasound images of the pyriform sinus from 35 subjects and 82 images of epiglottic vallecula from 26 of 35 subjects. The ultrasound images with fiberoptic endoscopic evaluation of swallowing showed that areas of high echogenicity in the pyriform sinus and epiglottic vallecula are related to the presence of pharyngeal residue. The presence of high-echogenicity areas resulted in a sensitivity of 92.0% and specificity of 71.9% for detecting pharyngeal residue in the pyriform sinus and a sensitivity of 86.7% and specificity of 63.6% for detecting pharyngeal residue in the epiglottic vallecula.

Conclusions: Transverse ultrasound scans at the level of the laryngeal prominence and above the hyoid bone enable the visualization of the pyriform sinus, epiglottic vallecula, and pharyngeal residue.