The role of ultrasound in evaluating salivary glands swellings

Abstract
Background
Viral infection is the most common cause of salivary gland swelling as mumps which mainly affects the parotid glands. Sialolithiasis is another cause of obstruction of the salivary duct. A tumor is another cause of swelling. Around 70% of salivary gland tumors arise from the parotid glands. Benign lesions represent 57% of these tumors. Three to 5% of all tumors affecting the head and neck are represented in the salivary gland. Ultrasonography is considered a basic diagnostic tool in all salivary gland swellings. Our study is to evaluate the role of ultrasound in the evaluation of salivary glands swellings in comparison with a computed tomography scan.

Results
A total of 80 patients aged more than 1 year old with swellings affecting the salivary glands were collected from the out-patient clinic during the period from February 2020 to February 2021. All patients underwent ultrasonography and computed tomography examination of the neck. All submandibular gland lesions presented with sialolithiasis (40 cases) (100%), and 20 cases (50%) of parotid gland swellings presented as inflammation without stone (16 cases (40%) of acute inflammation and 4 cases (10%) with recurrent inflammation), while 4 patients only presented as sialolithiasis. Neoplastic lesions were diagnosed in 16 cases of the parotid gland group. Stones less than 3 mm were detected only by computed tomography in 5 patients (12.5%) of the submandibular group. Twenty-eight cases (70%) with stones ranged in size between 3 and 6 mm. Only 11 cases (27.5%) with stones ranged in size more than 6 mm. Of the 16 parotid swellings diagnosed with neoplastic lesions, 14 parotid cases (87%) showed well-defined margins by computed tomography and ultrasonography.

Conclusions
Sonography is the basic diagnostic tool in salivary glands swellings. Ultrasonography should be the initial imaging modality. Only in special cases, such as stones that could not be detected by ultrasonography or a neoplastic lesion in a deep location, or bone infiltration, computed tomography neck should be performed.