Chapter 15 Lacrimal system and salivary glands
Digital Subtraction and CT Dacryocystography
Dacryocystography allows visualization of the lacrimal system by direct injection of contrast into the cannalicus of the eyelid. It may be combined with CT imaging performed immediately after lacrimal system contrast injection. CT imaging gives additional diagnostic information, particularly about adjacent structures.1
Technique
1. The lacrimal sac is massaged to express its contents prior to injection of the contrast medium. The lower eyelid is everted to locate the lower canaliculus at the medial end of the lid. The lower canaliculus is dilated and the cannula or catheter is inserted. The lower lid should be drawn laterally during insertion to straighten the bend in the canaliculus, and so avoid perforation by the cannula.
Aftercare
A protective eye patch for 30–60 min may be necessary in view of the local anaesthetic used.
