**First Report of Sublingual Gland Ducts: Visualization by Dynamic MR Sialography and Its Clinical Application**

**Tatsurou Tanaka 1, Masafumi Oda 1, Nao Wakasugi-Sato 1, Takaaki Joujima 1, Yuichi Miyamura 1, Manabu Habu 2, Masaaki Kodama 3, Osamu Takahashi 2, Teppei Sago 4, Shinobu Matsumoto-Takeda 1, Ikuko Nishida 5, Hiroki Tsurushima 6, Yasushi Otani 6, Daigo Yoshiga 6, Masaaki Sasaguri <sup>2</sup> and Yasuhiro Morimoto 1,\***


Received: 30 October 2020; Accepted: 11 November 2020; Published: 16 November 2020

**Abstract:** This study was done to determine whether the sublingual gland ducts could be visualized and/or their function assessed by MR sialography and dynamic MR sialography and to elucidate the clinical significance of the visualization and/or evaluation of the function of sublingual gland ducts by clinical application of these techniques. In 20 adult volunteers, 19 elderly volunteers, and 7 patients with sublingual gland disease, morphological and functional evaluations were done by MR sialography and dynamic MR sialography. Next, four parameters, including the time-dependent changes (change ratio) in the maximum area of the detectable sublingual gland ducts in dynamic MR sialographic images and data were analyzed. Sublingual gland ducts could be accurately visualized in 16 adult volunteers, 12 elderly volunteers, and 5 patients. No significant differences in the four parameters in detectable duct areas of sublingual glands were found among the three groups. In one patient with a ranula, the lesion could be correctly diagnosed as a ranula by MR sialography because the mass was clearly derived from sublingual gland ducts. This is the first report of successful visualization of sublingual gland ducts. In addition, the present study suggests that MR sialography can be more useful in the diagnosis of patients with lesions of sublingual gland ducts.

**Keywords:** MR sialography; dynamic; sublingual gland ducts
