Abstract
To assess the malignant potential of the tongue cancer by intraoral ultrasonography (US) and MR imaging (MRI), we examined 57 patients with squamous cell carcinoma of the tongue. Intraoral US using 7. 5M Hz linear microprobe and MR findings on Gd-DTPA enhanced T1-weighten image were examined with respect to the shape, the border, the internal signals, and the depth of invasion, respectively. On the intraoral US, 53 of 57 tumors (93.0%) excepting lesions less than 1 mm of pathologic depth of invasion were detected. On the other hand, tumor detection rate on the MRI was 89.0% . There were significant relationships between US findings and invasion and stromal reaction. Tumors invading diffusely in scchirous stroma exhibited irregular shapes, diffuse borders, and heterogeneous internal signals on the US. In addition, tumors invading 8.0 mm or more on US and MRI had developed neck metastasis in those less than 8.0 mm in the depth of invasion. Thus these US findings provide an useful information to predict the incidence of occult neck metastasis clinically N0 tumors. In conclusion, intraoral US combination with MRI is effective to evaluate tumor extent and its malignant potential. In case of excisional biopsy, particularly, the preoperative intraoral US should be performed routinely.
