A ultrasonic study was performed in 71 patients with various jaw diseases (benign and malignant tumors, cysts, fractures) using 3.5-MHz electronic scan and 5-MHz or 7.5-MHz arc scan in immersion method.
The results are summarized below.
Ultrasonograms can delineate not only soft tissues (skin, subcutaneous tissue, muscle tissue) but also jaw bones; however, only strong echoes from the surface can be obtained in the case of jaw.
The inside of bone is delineated in jaw diseases with destructed or thinned cortical bones. These internal echoes can be classified into three types as follows.
1. Cystic pattern: Anechoic pattern
2. Solid pattern: Echoic pattern
3. Mixed pattern: Anechoic and echoic patterns
Benign bone tumors and cysts in general demonstrated a bulging cortical margin distinct from the surrounding tissues. The internal echoes usually varied in cases of benign bone tumors, but those of bone cysts were of cystic pattern except for a solid pattern observed in one case due to the acoustic structure of the cyst contents.
Most of malignant tumors showed a solid pattern with irregular and/ or unclear margin. When a tumor invaded the surrounding tissues, the pattern there become hypoechogenic.
In the case of fracture, a displacement and separation of bone fragment was noted while the surrounding tissues showed a hypoechoic pattern with slightly well defined margin due to the degeneration of tissue. The postoperative course was objectively followed with time lapse by serial ultrasonic examination.
The ultrasonic examination is a valuable additional tool, providing important informations on jaw diseases.
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