Salivary Glands PDF

Salivary Glands ‫ ضياء الحمزاوي‬.‫د‬ Anatomy of Salivary Glands 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 major salivary glands in the decreasing order of thei...

Salivary Glands ‫ ضياء الحمزاوي‬.‫د‬ Anatomy of Salivary Glands 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 major 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. Imaging modalities Commonly used imaging methods include: 1. plain radiography 2. conventional sialography. 3. high-resolution ultrasonography (HRUS) is being increasingly used for targeted salivary gland imaging. 4. cross-sectional imaging techniques such as computed tomography (CT) and magnetic resonance imaging (MRI) have revolutionized the imaging of salivary glands. 5. Nuclear imaging  Radiography Projection images, whether (1) intraoral occlusal images or (2) extraoral panoramic images, are helpful in identifying calcified sialoliths. (1) (2) High resolution Ultrasonography It is the easiest and best imaging modality to evaluate the submandibular glands and to differentiate between benign and malignant tumours and to see stones. High-resolution ultrasonography image of the parotid gland demonstrating an echo-free mass with well-defined margins, which is typical of a cystic mass Multi-Detector CT (MDCT) MDCT, displayed in both bone and soft-tissue windows, is useful in evaluating not only the salivary glands but also the structures surrounding them. This is especially true when the images are acquired after intravenous administration of a contrast agent that renders glandular tissues hyperdense relative to the surrounding fat and muscle. Useful to see stones, infection, and tumours. MRI MRI is the best imaging method of choice for assessment of space- occupying lesions / tumours (cyst and neoplasms) of the salivary glands because of its superior soft-tissue contrast  Sialography Sialography is the only imaging technique that can assess both the morphology of the parotid and submandibular glands and function. The primary indication for sialography is chronic inflammatory conditions, especially when obstruction is suspected Types: 1. The technique involves infusion of the gland ductal system with an iodinated contrast agent, and then imaging the gland with projection imaging, fluoroscopy, MDCT, or cone beam computed tomography (CB CT). 2. MRI may be combined with sialography, but in these cases the patients' own saliva is used as a contrast agent and the imaging is done using heavily weighted T2 protocols.  Radiographic sialography CT Sialography MRI Sialography Nuclear medicine Nuclear medicine examinations are functional examinations of the salivary glands. This modality takes advantage of the selective uptake of specific radiopharmaceuticals such as technetium 99m (99mTc)- pertechnetate (TPT) by the salivary glands when injected intravenously. This is followed by administration of a sialagogue (stimulation) evaluate the secretory capacity of the salivary glands. 1. Which of the following imaging modalities is most suitable for assessing space-occupying lesions in the salivary glands? A) Plain radiography B) High-resolution ultrasonography (HRUS) C) Multi-Detector CT (MDCT) D) MRI Answer: D) MRI 2. What is the primary indication for performing sialography? A) Detecting salivary gland neoplasms B) Assessing chronic inflammatory conditions C) Identifying salivary ductal stones D) Evaluating space-occupying lesions Answer: B) Assessing chronic inflammatory conditions 3. Which salivary gland is best evaluated using high-resolution ultrasonography (HRUS)? A) Parotid gland B) Submandibular gland C) Sublingual gland D) Minor salivary glands Answer: B) Submandibular gland 4. Technetium-99m (99mTc)-pertechnetate is primarily used in nuclear medicine imaging of the salivary glands to: A) Visualize the morphology of salivary ducts B) Assess the secretory function of the glands C) Detect calcifications in the gland D) Diagnose acute infections Answer: B) Assess the secretory function of the glands 5. Which of the following is true regarding conventional sialography? A) It uses plain radiography for imaging B) It is the imaging modality of choice for salivary gland tumors C) It involves the infusion of a gland ductal system with an iodinated contrast agent D) It provides superior soft-tissue contrast Answer: C) It involves the infusion of a gland ductal system with an iodinated contrast agent