Cone-Beam Computed Tomography (CBCT) Dacryocystography for Imaging of the Nasolacrimal Duct System

Purpose:To evaluate the usefulness and safety of cone-beam computed tomography (CBCT) dacryocystography in detectinglesions, identifying coexisting soft-tissue changes and determining treatment options in patients with epiphora.Patients and Methods:Unilateral digital subtraction dacryocystography and CBCT dacryocystography were carried out on45 patients. Stenoses and occlusions were identified and coexisting changes such as septal deviation and dacryoliths werenoted. The diameter of the bony lacrimal duct of affected and unaffected side was measured and related to the clinicallyevident epiphora. An attempt was made to base the subsequent therapeutic planning on the CBCT dacryocystographicfindings. Additionally, the radiation dose levels for CBCT dacryocystography in comparison to those of multislice computedtomography (MSCT) were evaluated in a standardized head-neck Rando-Alderson phantom.Results:Nasolacrimal duct obstructions were present in 37/45 patients, 18 with a stenosis and 19 with an occlusion inparts of the lacrimal outflow system. The minimal bony diameter of the side with epiphora was significantly decreasedcompared to the unaffected side. Coexisting soft-tissue changes did not correlate significantly with the clinical sign ofepiphora. Eight patients showed no underlying reason for the epiphora and were treated conservatively. A total of elevenpatients received interventional therapy for their stenosis and 23 patients had to be treated surgically. A further threepatients received medical treatment for infection, before surgery and interventional therapy, respectively, were carriedout. Dose levels for CBCT imaging remained far below those of MSCT.Conclusion:CBCT dacryocystography is a safe and time-efficient modality for assessing the nasolacrimal duct system inpatients with epiphora. CBCT dacryocystography provides detailed images of the nasolacrimal drainage system, surroundingsoft tissue, and bony structures in one diagnostic tour. It allows clear measurement of the bony nasolacrimal duct anddisplays information beyond that of the drainage lumen, improving the planning of therapeutic interventional and surgicalprocedures.