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Dacryoscintigraphy (DSG), also known as lacrimal scintigraphy, is a nuclear medicine technique for imaging the lacrimal apparatus. It is used to identify obstructions, for example in the lacrimal duct , nasal cavity or nasolacrimal duct .
The lacrimal apparatus is the physiological system containing the orbital structures for tear production and drainage. [1]It consists of: The lacrimal gland, which secretes the tears, and its excretory ducts, which convey the fluid to the surface of the eye; it is a j-shaped serous gland located in lacrimal fossa.
Involutional stenosis is probably the most common cause of nasolacrimal duct obstruction in older people. It affects women twice as frequently as men. Although the inciting event in this process is unknown, clinicopathologic study suggests that compression of the lumen of the nasolacrimal duct is caused by inflammatory infiltrates and edema.
The lacrimal gland is a compound tubuloacinar gland, it is made up of many lobules separated by connective tissue, each lobule contains many acini.The acini composed of large serous cells which, produce a watery serous secretion, serous cells are filled with lightly stained secretory granules and surrounded by well-developed myoepithelial cells and a sparse, vascular stroma.
The lacrimal papilla is an elevation in the inner side of the eyelid, at the edge of the lacrimal lake. [10] The lacrimal canaliculi open into the papilla. [10] The opening of each canaliculus is the lacrimal punctum. From the punctum, tears will enter the lacrimal sac, [2] then on to the nasolacrimal duct, and finally into the nasal cavity. [10]
The lacrimal sac or lachrymal sac [1] is the upper dilated end of the nasolacrimal duct, [2] and is lodged in a deep groove formed by the lacrimal bone and frontal process of the maxilla. It connects the lacrimal canaliculi , which drain tears from the eye's surface, and the nasolacrimal duct , which conveys this fluid into the nasal cavity. [ 3 ]
Causes of epiphora are any that cause either overproduction of tears or decreased drainage of tears, resulting in tearing onto the cheek. [2] This can be due to ocular irritation and inflammation (including trichiasis and entropion) or an obstructed tear outflow tract, which is divided according to its anatomical location (i.e., ectropion, punctal, canalicular or nasolacrimal duct obstruction).
Haemolacria can manifest as tears ranging from merely red-tinged to appearing to be entirely made of blood, [1] and may also be indicative of a tumor in the lacrimal apparatus. It is most often provoked by local factors such as bacterial conjunctivitis, environmental damage or injuries. [2]