Watery eye following patent external DCR: an MR dacryocystography study

To examine patients with persistent watery epiphora following patent external dacryocystorhinostomy (DCR) with magnetic resonance imaging dacryocystography (MR-DCG).

Patients with unobstructed nasolacrimal irrigation following external DCR were included. Five patients with watery epiphora constituted the study group (SG). Five patients without epiphora constituted the control group (CG). All patients underwent MR-DCG following the instillation of artificial tears in the conjunctival fornix. The osteotomy site was identified in T1-weighted coronal images. Lacrimal flow was assessed with modified T2-weighted (True Fast Imaging Steady State Pulse, "TrueFISP") coronal images before and 10 min after repeated blinking. Signal intensities at three regions of interest (ROIs), corresponding to the eyeball (ROI-1), conjunctival sac (ROI-2), and anastomotic site (ROI-3) were measured.

Differences in the diameter of both osseous and soft tissue ostia between SG and CG were statistically not significant. A post-blink increase in signal intensity at ROI-3 was noted in both groups, whereas differences in signal intensity for ROI-1 and ROI-2 were statistically not significant. The post-blink signal intensity increase in ROI-3 was significantly more pronounced in the CG, compared with the SG.

The fact that signal intensity increase at ROI-3 was less pronounced in the SG, compared with CG, implies a compromised "lacrimal pump" mechanism in the former group. The methodology presented may be used for the evaluation of post-DCR epiphora.