Comparison of the inadequacies of ultrasonography and computed tomography in the diagnosis of sialolithiasis

Abstract

This study aimed to determine the value of either ultrasonography and computed tomography (CT) alone or both for diagnosing salivary gland stones. Based on their clinical findings and physical examination, 188 patients with salivary stones were included. Initially, an ultrasound was performed, and then a non-contrast-enhanced thin-sliced CT scan was done. The study included 161 patients with suspected submandibular gland (SMG) sialolithiasis and 27 with parotid gland (PG) sialolithiasis. Among the SMG cases, stones were confirmed in 130 patients through interventional sialoendoscopy. Sixteen of the stones were detected by CT scan only and were not seen in the previous ultrasound examination. After the second follow-up ultrasound, which was conducted after reviewing the CT scans, 9 of them were identified. Five patients with distal stones and ductal dilation on ultrasound were confirmed to have sialolithiasis. In 5 patients with stones detected on ultrasound but not on CT, dental filling artifacts were identified as the cause. For PG cases, stones were observed in 18 out of 19 patients with suspected sialolithiasis based on ultrasound and CT findings. Three patients with positive CT findings but negative ultrasound showed stones during sialendoscopy. During an ultrasound examination, palpating the floor of the mouth with the other hand’s index finger can help identify stones obscured by the shadow of the mandible, thereby enhancing the test’s accuracy. Patients with dental fillings, implants, and permanent dentures should not be referred for a CT scan to avoid unnecessary exposure to ionizing radiation. They also cause significant metallic artifacts in the field of interest. In these cases, ultrasound should be considered. To minimize the effects of ionizing radiation, it is recommended to create limited field requests for the target, focusing solely on the submandibular and PGs.