Abstract
As gray-scale ultrasonographic examination has the advantages of being noninvasive, rapid and easily repeated, this method can be a valuable diagnostic aid for oral lesions. Generally, ultrasonographic examination of oral lesions has been carried out by placing a transducer on the subjects' facial skin, since the oral cavity is too small to insert the transducer. Using this extraoral approach, it is difficult to obtain data from the tongue edge, palate and gingiva because the air space in the oral cavity is a deterrent to acoustic transmission.
To resolve these problems, an intraoral transducer has been newly developed and employed clinically in the examination of oral lesions. This transducer is characterized by a pulsed 2-9MHz ultrasonic beam and a 3cm long linear array of 26 piezoelectric crystals. Phantom examination revealed that this system has capability of 3cm focus, 1mm axial resolution and 2mm lateral resolution.
It can be inserted into the oral cavity with a water bag or agar used as a coupling agent, and placed securely against the oral mucosa, allowing ultrasound images of many areas in the oral cavity to be easily observed.
Clinical application of this technique to oral lesions can distinguish between cystic, solid and complex characteristics of the lesions, and also yield size, shape, location and relationship to adjacent structures. To a cleft palate, the width of bony cleft is measured. These ultrasonic patterns are similar to the findings of excised materials and surgical exploration.
These results suggest that intraoral ultrasound scanning can be useful for the diagnosis of the oral lesions.
