Contribution of MRI for 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 fo r problems in patients with an assumed permeable outflow system who develop epiphora. Patients and methods : A prospective study of nine patients, including 2 as ymptomatic controls was conducted. The magnetic resonance protocol included , gadolinium instillation into the conjunctival cul-de-sac, 3D gradient-ech o T1-weighted acquisition, 2 mm thick images passing throught the nasolacri mal 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 la crimal transit time of a median 100 seconds. Three distinct events were ind ividualized: gadolinium arrival in the lacrimal sac (t1), at the extremity of the bony portion of the lacrimal duct (te), and the extremity of the muc osal portion of the duct (t3). Patients with an assumed permeable outflow s ystem who had epiphora show results intermediary between passed dye and tot al blocage of the dye within the lacrimal sac. Conclusion : The study of the lacrimal outflow system using this new magnet ic resonance imaging protocol contributes to the physiological study of tea r evacuation and could be useful for quantitative assessement of lacrimal s tenosis, particularly interesting for therapeutic guidance.