MR dacryocystography: comparison with dacryoendoscopy in positional diagnosis of nasolacrimal duct obstruction

Purpose To compare the findings of MR dacryocystography with those of dacryoendoscopy and subsequent surgery in patients with nasolacrimal duct obstruction, and to determine the efficacy of MR dacryocystography in the positional diagnosis of nasolacrimal duct obstruction. Materials and methods Thirty-one patients with clinically suspected nasolacrimal duct obstruction who underwent MR dacryocystography and dacryoendoscopy with subsequent surgical procedure were included. MR dacryocystography was performed by using heavily T2-weighted fast spin echo sequence in the coronal and axial planes after the topical administration of normal saline drops into the conjunctival sacs. Results In MR dacryocystography, stenosis/obstruction at the canalicular level was correctly diagnosed in nine patients (100 %). Stenosis/obstruction at the lacrimal sac level was correctly diagnosed in 14 of 16 patients (87.5 %) in MR dacryocystography. Three patients with coexistent stenosis/obstruction at both the canalicular and the lacrimal sac level were misinterpreted as stenosis/obstruction at the canalicular level on MR dacryocystography. The overall accuracy of MR dacryocystography in depicting stenosis/obstruction was 84 %. Conclusions MR dacryocystography after the topical administration of normal saline drops into the conjunctival sacs is a well-tolerated, minimally invasive imaging technique to identify the level of stenosis/obstruction in patients with nasolacrimal duct obstruction before dacryoendoscopy and subsequent surgery.