SUMMARY

Dacryocystography remains as one of the most important exams in the evaluation of the excretory lacrimal ducts. Its technology, however, has not changed much since it was first used. Dacryocystography with digital subtraction (DCGDS) is done with a computer controlled X-ray device. The selected images are subjected to a digital subtraction technique where the overlapped structures of the skull are removed, thus, obtaining much purer images of the excretory lacrimal ducts. These images are rich in detail and far better than the ones obtained with the conventional technique (DCG). It also allows to dynamically observe the flow of the contrast medium as soon as the exam begins, a from the canaliculli to the kinetic progression of the contrast along the excretory lacrimal ducts. In this work, DCGDS was done in 19 patients (12 female and 7 male) with ages ranging from 8 months to 51 years. In order to inject the contrast (Hypaque 75%) two Butterfly 23G were adapted as lacrimal cannulae. They were both previously prepared by cutting the two wings and removing the needles tip. A Y type connection attached to extension tubes allowed us to connect the two cannulae to a syringe, thus making it possible a bilateral and simultaneous injection of hydrosoluble contrast medium.

The DCGDS technology brings significant advantages over the traditional DCG. Its usage is recommended for special cases whenever the equipment is available.

Key words: Lacrimal apparatus; Digital subtraction dacryocystography; Image processing computer-assisted