title: Cone-Beam Computed Tomography (CBCT) dacryocystography for imaging of the nasolacrimal duct system.
abstract: OBJECTIVE
  To evaluate the usefulness and safety of cone-beam computed tomography (CBCT) dacryocystography in detecting lesions, identifying coexisting soft-tissue changes and determining treatment options in patients with epiphora.
  
  
  METHODS
  Unilateral digital subtraction dacryocystography and CBCT dacryocystography were carried out on 45 patients. Stenoses and occlusions were identified and coexisting changes such as septal deviation and dacryoliths were noted. The diameter of the bony lacrimal duct of affected and unaffected side was measured and related to the clinically evident epiphora. An attempt was made to base the subsequent therapeutic planning on the CBCT dacryocystographic findings. Additionally, the radiation dose levels for CBCT dacryocystography in comparison to those of multislice computed tomography (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 in parts of the lacrimal outflow system. The minimal bony diameter of the side with epiphora was significantly decreased compared to the unaffected side. Coexisting soft-tissue changes did not correlate significantly with the clinical sign of epiphora. Eight patients showed no underlying reason for the epiphora and were treated conservatively. A total of eleven patients received interventional therapy for their stenosis and 23 patients had to be treated surgically. A further three patients received medical treatment for infection, before surgery and interventional therapy, respectively, were carried out. Dose levels for CBCT imaging remained far below those of MSCT.
  
  
  CONCLUSIONS
  CBCT dacryocystography is a safe and time-efficient modality for assessing the nasolacrimal duct system in patients with epiphora. CBCT dacryocystography provides detailed images of the nasolacrimal drainage system, surrounding soft tissue, and bony structures in one diagnostic tour. It allows clear measurement of the bony nasolacrimal duct and displays information beyond that of the drainage lumen, improving the planning of therapeutic interventional and surgical procedures.
authors: Department of Radiology, University Hospital Bonn, Germany. kai.wilhelm@ukb.uni-bonn.de
authors: Kai E
authors: KE
authors: Wilhelm
authors: Heike
authors: H
authors: Rudorf
authors: Susanne
authors: S
authors: Greschus
authors: Stefan
authors: S
authors: Garbe
authors: Marcel
authors: M
authors: Lüssem
authors: Thomas
authors: T
authors: Lischka
authors: Hans H
authors: HH
authors: Schild
authors: Andreas O H
authors: AO
authors: Gerstner
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D054893:Cone-Beam Computed Tomography / Q000379:methods*; D003238:Connective Tissue / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007766:Lacrimal Apparatus Diseases / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D009301:Nasolacrimal Duct / Q000002:abnormalities* / Q000000981:diagnostic imaging*; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity