Digital Subtraction Dacryocystography

Abstract

Dacryocystography (DCG) is a modality where the lacrimal drainage system is injected with a radiopaque dye and roentgenograms are obtained to study obstructions or filling defects. However, the plain X-ray DCG has a poor resolution and lacrimal system is not highlighted for a detailed study. Digital subtraction DCG or DS-DCG was first described by Galloway et al. in 1984 [1]. Digital subtraction dacryocystography is currently the most favored among conventional X-ray techniques. As the name reflects, this technique can subtract background images and noises to give clear contrast-filled lacrimal images for study. Its other advantages include reduced radiation exposure as compared to conventional techniques, ability to digitally manipulate the image contrast and brightness, and cinematic view helping with understanding the flow dynamics. DCG is a useful modality to study the anatomical abnormalities of the lacrimal system like stenosis, obstructions, and diverticula and to detect dacryolithiasis [1–5].