Pictorial essay: Salivary gland imaging

Abstract

Salivary glands are the first organs of digestion secreting their digestive juices into the oral cavity. Parotid, submandibular, and sublingual glands are the major paired salivary glands in the decreasing order of their size. In addition, multiple small minor salivary glands are noted randomly distributed in the upper aerodigestive tract, including paranasal sinuses and parapharyngeal spaces. The imaging is directed to the major salivary glands. Commonly used imaging methods include plain radiography and conventional sialography. Recently, high-resolution ultrasonography (HRUS) is being increasingly used for targeted salivary gland imaging. However, the advent of cross-sectional imaging techniques such as computed tomography (CT) and magnetic resonance imaging (MRI) have revolutionized the imaging of salivary glands. This article illustrates the role of imaging in evaluating the variegated disease pattern of the major salivary glands.

Practical Imaging of the Parotid Gland

“…In approximately 10%-20% of the general population, an accessory parotid gland is also present, extending anteriorly along the main parotid duct (Stensen duct), superficial to the masseter muscle. 2 A normal parotid gland contains both adipose and glandular tissue in variable proportions, resulting in a multivariate appearance on crosssectional imaging 3 (Fig 1). Several branches of the external carotid artery supply blood to the parotid gland; venous drainage occurs via the internal jugular vein.…”

The Role of Magnetic Resonance Imaging and Magnetic Resonance Sialography in the Diagnosis of Various Salivary Gland Disorders: An Interobserver Agreement

“…Imaging techniques of the salivary glands include plain radiography, sialography, ultrasonography, computed tomography, magnetic resonance imaging (MRI), and salivary gland scintigraphy [2][3][4]. MRI has several advantages over other diagnostic imaging procedures because it offers excellent soft tissue contrast resolution, no ionizing radiation is involved, and direct multiplanar imaging is possible without reorienting the patient [5].…”

MR Sialography and Conventional Sialography in Salivary Gland and Duct Pathologies: A Comparative Study

“…In chronic stages, the gland may be normal or small in size with decreased echogenicity and vascularity and heteroechoic pattern. (7,6) On CT and MR imaging, sialadenitis appears as moderate-to-intensely enhancing, diffusely enlarged salivary gland with or without abscess formation. Intraparenchymal and regional lymphadenopathy may be present.…”

“…The differential diagnosis for abscess include superinfected HIV related cysts, suppurative parotid lymph nodes and cystic degeneration of neoplasms with or without superimposed infection. (6,10,8,9) The most common cause of acute sialadenitis is infection. This is most commonly due to pathogens ascending from the oral cavity due to decreased salivary flow in conditions like prior infections, dehydration, surgery, irradiation and obstructing lesions such as stones or tumours.…”

“…Plain radiographs were obtained in standard antero-posterior and lateraloblique projections to detect radiopaque sialoliths. (1,5,6) Secretagogue-like fresh lemon was used before the commencement of the study, so that the intraoral opening of the parotid and submandibular ducts could be visualised well. After identifying the opening, lacrimal dilators are used to dilate it to facilitate cannulation.…”