Masaaki Kodama

Various modalities are available for the diagnosis of diseases affecting the oral and maxillofacial regions and the accuracy of diagnosis for many kinds of diseases in oral and maxillofacial regions is readily increasing. In particular, considerable research has focused on the use of magnetic resonance (MR) images for functional evaluation, as well as morphological examination, due to the high spatial resolution of the images, the fast acquisition time, and the image processing techniques associated with the growing computational power and improvements in the MR system. Therefore, we developed and named “Dynamic MR sialography”, a new technique for the functional evaluation of salivary glands using continuous MR sialography pre- and post-citric acid stimulation on the tongue. In the present review, we focused the “Dynamic MR sialography”, and introduce the methods, applications and significances of its technique in the diagnostic process of salivary glands-related diseases. In addition, we review the significance of the prognostic evaluation for the improvement of saliva flow rate after saline solution irrigation treatment.

Background: Recent studies suggest that tonsilloliths are clinically related to halitosis and tonsillar abscess. Based on our empirical knowledge, tonsilloliths are relatively commonly encountered in daily clinical practice. It has been reported that the detection rate of tonsilloliths was under 24% in previous reports, although experience suggests otherwise. The purpose of the study was to evaluate the prevalence and characteristics of tonsilloliths using computed tomography (CT). In addition, the possible causes of low detection rates on panoramic radiographs were evaluated based on comparisons between CT images and panoramic radiographs in order to elucidate the limitations of visualizing the area around the palatine tonsils on panoramic radiographs. Methods: 482 pairs of CT images and panoramic radiographs were retrospectively assessed with respect to the presence and characteristics of tonsilloliths. In addition, the causes in cases of disagreement between the two modalities were analyzed. Results: The detection rate of tonsilloliths was 46.1% using CT scans, unlike previous reports. The characteristics of tonsillolith were dot-like figures with about 300-500 Hounsfield units within the palatine tonsil under the soft palate. The most common length of tonsilloliths was about 3 or 4 mm. As the subjects aged, the detection rate increased gradually. A significant difference in the tonsillolith detection rate was found between the over and under 40-year-old groups (p < 0.0001). However, the detection rate of tonsilloliths was only 7.3% on panoramic radiographs. A significant correlation was observed between the detection rate of tonsilloliths on panoramic radiographs and CT number (Spearman r = 0.429), size, (Spearman r = 0.318), and number of tonsilloliths (Spearman r = 0.333). Conclusion: The present results suggest that tonsilloliths are relatively more common than previously suggested. However, panoramic radiographs detect only a small percentage of palatine tonsilloliths. The low detection rates on panoramic radiographs might be related to the degree of calcification, size, and number of tonsilloliths.

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