大唾液腺ならびにその周辺領域の疾患に対するＭＲＩ診断の臨床的研究

Abstract

The diagnostic value of magnetic resonance imaging (MRI) for lesions situated in the major salivary glands was clinically discussed in this study. A total of 46 patients with salivary gland disorders treated in our department over the past five years were assessed by mean of MRI, and in 11 patients the findings were compared with the histopathological features of lesions sectioned at the same level postoperatively. In addition, preliminary investigations to introduce a new qualitative diagnostic procedure for estimation of salivary gland function in geriatric patients were attempted. In this investigation, T1 and T2 values, and signal intensity ratios of the submandibular gland were measured in elderly patients complaining of dry mouth and in healthy controls. Likewise, salivary gland function was examined by taste stimulation induced by applying citric acid to the tongue surface just before starting MRI. The results of these trials were as follows:1 MRI clearly demonstrated lesions in the salivary glands.2. The histopathological diagnosis could not be accurately predicted by signal intensity. However, benign tumors showed higher intensity signals than did malignant tumors in T2-weighted images.3. Cystic lesions could be differentiated from tumors by signal intensity.4 Histopathological features of salivary gland tumors corresponded to the MRI signal intensity.5. Relaxation times of T1 and T2, values and signal intensity in each major salivary gland were diminished in elderly patients in a resting condition.6. Only T1 values in healthy subjectives remarkably responded to taste stimulation.These results suggest that MRI is useful and beneficial not only in the qualitative diagnosis of tumors arising from salivary glands but also in the estimation of salivary gland function. MRI should therefore be included in routine diagnostic examinations for salivary gland disorders.