[Contribution of MRI in the dynamic study of the lacrimal outflow system].

PURPOSE

To evaluate a new magnetic resonance imaging protocol for dynamic study of the lacrimal outflow system and to use this protocol to search for problems in patients with an assumed permeable outflow system who develop epiphora.

PATIENTS AND METHODS

A prospective study of nine patients, including 2 asymptomatic controls was conducted. The magnetic resonance protocol included, gadolinium instillation into the conjunctival cul-de-sac, 3D gradient-echo T1-weighted acquisition, 2 mm thick images passing through the nasolacrimal duct, dynamic acquisition after gadolinium instillation for timing dye progression through the outflow system.

RESULTS

Similar results were obtained for the two control subjects with lacrimal transit time of a median 100 seconds. Three distinct events were individualized gadolinium arrival in the lacrimal sac (t1), at the extremity of the bony portion of the lacrimal duct (té), and the extremity of the mucosal portion of the duct (t3). Patients with an assumed permeable outflow system who had epiphora show results intermediary between passed dye and total blockage of the dye within the lacrimal sac.

CONCLUSION

The study of the lacrimal outflow system using this new magnetic resonance imaging protocol contributes to the physiological study of tear evacuation and could be useful for quantitative assessment of lacrimal stenosis, particularly interesting for therapeutic guidance.