Considerable advances have been made in the application of a new use of duplex Doppler imaging to analyze the motion of the hyoid bone during swallowing. Using this technique, we provide both real-time, two-dimensional B-mode scans and a spectrum of Doppler-Shift frequencies of a moving object (the hyoid bone). Because the Doppler-Shift spectrum delineates the velocity distribution of the hyoid bone and its muscular attachments, a trajectory of hyoid motion can be calculated. Additionally, we found that velocity spectra displayed the patterns of motion characteristic of hyoid movement. Velocity information permits calculation of durational measures of an entire oropharyngeal swallow. Validation of the ultrasound duplex Doppler technique was completed on two normal swallowers. Minimal variation was found within normal subjects, thus giving highly reliable data to use in future studies of abnormal subjects. Our efforts in using noninvasive, real-time ultrasound imaging to reconstruct the tongue have been highly successful. Considerable progress has been made in developing techniques to automate the three-dimensional ultrasound imaging and reconstruction procedure. Modifications were made during the ultrasound video image digitizing and contour tracing processes. Advanced contour tracing procedures are being used as well. We used a position sensor to locate the ultrasound transducer during image acquisition to enable three- dimensional registration of the two-dimensional images. Tongue surface configurations have been reconstructed at rest, during bolus containment in the oral phase of swallowing, and during articulation of sustained vowels. This procedure will be applied to reconstruction of tumor sites in future investigations in our laboratory.
