- -term used to denote radiologic examination of nasolacrimal drainage system
- -done by filling the lumina of the canals with radiopaque medium
- -performed in the investigation of abnormalities of the passage as defective development, stenosis and chronic mucosal thickening
Examination Procedure
This preliminary radiograph are taken to evaluate the paranasal sinuses
- Waters
- Caldwell
- Lateral
- to expedite filming after the introduction of contrast medium, injection is carried out with patient seated before a vertical grid device
- patient may however be placed in supine position for introduction of medium and prone position for filming
- after anesthetizing the conjunctiva and puncta, physician dilates the punctum of the canaliculus to be injected
- then inserts the round-tipped lacrimal needle into the canaliculus.
- patency of the canals is tested by irrigating them with normal saline solution and if fund patent, examination is terminated
- immediately following the introduction of the contrast agent and withdrawal of needle, radiographs are taken in rapid succession in Caldwell, waters and lateral position
- same images are repeated at specified intervals to follow the progress of the medium though the channels.
- 7-10 minutes of post injection interval are taken for follow-up radiograph and again 15-20 minutes interval at which the medium will passed through the patient ducts and seen on the floor of the nasal cavity and on pharyngeal mucosa
- collateral side may be injected after the initial filming of the 1st side and its necessary to rotate head slightly (10-15º) away from the film in order to separate the shadow of bilaterally opacified ducts in lateral projection
- exposure factors used for routine paranasal sinus studies are satisfactory for the contrast studies of nasolacrimal duct system