Objectives: Dacryographies and CT dacryographies are usually performed after catheterization of a lacrimal canaliculus. We evaluated the quality of opacification on CT scan after simple instillation of contrast medium, without any catheterization.
Patients and methods: 39 patients (78 nasolacrimal ducts) were examined for lacrimal pathways obstruction by CT scan after instillation of diluted contrast medium. Additional CT scan imaging was performed after catheterization when the first study did not provide adequate opacification.
Results: CT dacryography after instillation is a well tolerated technique. In our study, it allowed detection of all pathologic lacrimal ducts; 7 normal lacrimal pathways (after catheterization) were not opacified after instillation (false positives). The sensitivity of the method was 100%, its specificity 84%.
Conclusion: CT dacryography after instillation is a physiologic, simple and sensitive method to evaluate lacrimal obstruction. We propose it as a first step, catheterization being used only in the absence of opacification after instillation.