The Application Of Computed Tomographic Dacryocystography In Lacrimal Duct Obstruction

Objective：To evaluate the application of computed tomographic dacryocystography(CT-DCG) in lacrimal duct obstruction.Methods:Fifty patients(one hundred eyes) were undergone the CT-DCG, observedlacrimal duct and its surrounding anatomic structures through CT axial, coronal andsagittal, used CT post-processing techniques to measure the size of the lacrimal sacfrom CT all levels, and analyzed relevant data. For the chronic dacryocystitis patientswith endoscopic endonasal dacryocystorhinostomy, measuring the distance oflacrimal sac top, bottom and middle turbinate axillary plane, guided the incisionlocation, and analyzed the extent consistent of the measurement results andintraoperative exposure of the actual position of lacrimal sac.Result：100eyes of CT-DCG tips,40normal eyes,60lacrimal duct diseases eyes.Lacrimal duct diseases eyes included lacrimal canaliculus obstruction4eyes(6.67%),lacrimal canaliduli obstruction2eyes(3.33%), nasolacrimal duct obstruction54eyes(90%), where chronic dacryocystitis46eyes(76.67%), recurrent dacryocystitis3eyes(5%), lacrimal sac cyst5eyes(8.33%).There was statistical significant difference of lacrimal sac size and maximumapproximate area of all levels between normal eyes and chronic dacryocystitis(p<0.05), and the chronic dacryocystitis was larger than the normal eyes.The average distance between lacrimal sac top and middle turbinate axillaryplane was7.124±2.147mm, the average distance between lacrimal sac bottom andmiddle turbinate axillary plane was4.974±2.344mm. In this study,13cases(16eyes)with chronic dacryocystitis patients received endoscopic endonasal dacryocystorhino-stomy, preoperative measurements obtained by CT-DCG with middle turbinateaxillary basis of lacrimal sac in the position of the lateral nasal wall and intraoperativeexposure of the lacrimal sac was consistent. CT-DCG could display the surrounding anatomic structures of lacrimal duct, that had an important role in the endoscopicendonasal dacryocystorhinostomy.Conclusion:CT-DCG and CT post-processing techniques:①can clarify the specificobstruction part of the lacrimal duct diseases;②can measure the size of the lacrimalsac from CT all levels;③can accurately locate the site of lacrimal sac in theprojection parts of the lateral nasal wall and display the lacrimal duct and itssurrounding anatomic structures, that can guide the endoscopic endonasaldacryocystorhinostomy.