Diagnostic value of high-frequency ultrasound for submandibular gland sialolithiasis

The purpose of the study was to evaluate the diagnostic value of combined use of linear-array and intracavity high-frequency transducers in submandibular gland sialolithiasis. This retrospective study involved 77 cases with surgically confirmed submandibular gland sialolithiasis. All patients underwent high-frequency ultrasound with linear-array and intracavity transducers before surgery. Submandibular gland size, shape, echogenicity, blood supply, duct dilation, and other sonographic characteristics were carefully analyzed. Using linear-array high-frequency transducer, among the 77 cases with submandibular gland sialolithiasis, 63 cases were correctly diagnosed before operation, 13 cases had missed diagnoses and 1 case was wrongly diagnosed, resulting in an accurate diagnosis rate of 81.8% (63/77). However, using linear-array together with intracavity transducer, 72 cases were correctly diagnosed before operation, 4 cases had missed diagnoses and 1 case was wrongly diagnosed, resulting in an accurate diagnosis rate of 93.5% (72/77). According to location, submandibular gland sialolithiasis was divided into four types: type I, intra-gland stones only; type II, hilum or gland-duct junction stones, with or without intra-gland stones; type III, extra-gland stones (stones in the main duct), with or without intra-gland stones; and type IV, intraductal stones at mouth floor close to the ductal opening. Among 17 cases of type III sialolithiasis, 9 were detected by linear transducer and another 7 were detected by additional use of intracavitary transducer under the chin. Two cases of type IV sialolithiasis were detected by putting intracavity transducer under the chin, whereas they were not detected using linear transducer. In conclusion, combined use of linear-array and intracavity high-frequency transducers enables scanning from multiple directions, which leads to improved visualization and high accuracy in detecting submandibular gland sialolithiasis.