2004 Volume 8 Issue 1 Pages 26-38
When a bolus is formed and maintained during swallowing，the oral cavity and pharynx cavity are interrupted by the contact of the tongue and the palate．Dysphagia is often induced with this interrupting dysfunction．There are many methods of evaluating the tongue surface shape in forming a bolus by two-dimensional measurements，but it is too difficult to evaluate the whole tongue shape．In this paper，standardization using a three-dimensional ultrasound system was researched to clarify the involvement of dysphagia in the defectiveness and/or dysfunction of the tongue and the palate．Characteristic changes of tongue shape in holding water on its surface were examined according to the volume of water bolus．The subjects were six healthy adult males (average age 26.0 years old)．The operation of the ultrasound probe was standardized by using an electronic motor to improve the image accuracy before evaluating the tongue shape．An aluminum marker was stuck on the tongue surface as a reference．A certain volume of water was held in the mouth，and a three-dimensional image of the tongue shape was scanned by the probe from the submandible．Measurement of the tongue and the palate contact was done in three directions (width，rear length，and depth) with the reference marker．It was suggested that the least distortion was achieved for probe settings of rotation radius of 20 cm，rotational speed of 1.6°/s and frequency of 6.0 MHz for tongue imaging．Using 3-D US，the tongue surface shape and its changes could be measured objectively，and most of the objects corresponded to a change in the volume of bolus by three-dimensionally changing the tongue surface shape．This three-dimensional tongue shape observation with forming a bolus is effective for evaluating and diagnosing not only abnormal forms of the tongue but also functional disorders．
