Evaluation of epiphora by topical contrast-enhanced CT and MR dacryocystography: which one to choose?

Topical CTD and MRD are non-invasive techniques that can visualize the degree and level of obstruction in the NLDS than conventional invasive cannulation dacryocystography. CTD is useful in visualizing the point of obstruction and smaller drainage structures. However, it is a source of ionizing radiation to the lens. The benefit of MRD is that it requires no contrast or radiation; however, it is poor in depicting the bone anatomy and smaller drainage structures. Finally, saline was better tolerated by patients than topical contrast.