title: Helical computed tomographic dacryocystography and its role in the diagnosis and management of lacrimal drainage system blocks and medial canthal masses.
abstract: OBJECTIVE
  To study the indications, technique and diagnostic utility of helical computed tomographic dacryocystography (CTDCG).
  
  
  METHODS
  Retrospective analysis of 13 patients who underwent CTDCG with subsequent surgical intervention, during the period January 2003 to December 2005, was done. Axial plain computed tomography (CT) scan was performed, followed by administration of water-soluble contrast in the conjunctival cul de sac or by cannulation of the lacrimal passages. Thin-slice helical CT with two-dimensional (2D) and three-dimensional (3D) coronal and sagittal reformation was done.
  
  
  RESULTS
  Four patients were males and 9 were females. Age range was 5 to 62 years. Seven patients presented with watering and 6 patients with a medial canthal mass. Three patients had history of trauma. CTDCG was performed by instillation technique in 10 patients and by cannulation in 3 patients. CTDCG showed mass lesion displacing the sac in 5 cases, nasolacrimal duct obstruction in 6 cases and mucocele in 2 cases. Based on the findings on CTDCG, 5 patients underwent mass excision, 7 underwent dacryocystorhinostomy and 1 patient underwent primary silicone tube intubation.
  
  
  CONCLUSIONS
  Helical CTDCG is a safe and useful diagnostic tool for the lacrimal surgeon. Instillation technique is a physiological and convenient method, and cannulation is needed only in cases where adequate visualization is not achieved.
authors.affiliation: Medical Research Foundation, Chennai, India.
authors.forename: Priti
authors.initials: P
authors.lastname: Udhay
authors.forename: Olma Veena
authors.initials: OV
authors.lastname: Noronha
authors.forename: Ravindra E
authors.initials: RE
authors.lastname: Mohan
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D003287:Contrast Media; D005260:Female; D006801:Humans; D007765:Lacrimal Apparatus / Q000000981:diagnostic imaging*; D007767:Lacrimal Duct Obstruction / Q000000981:diagnostic imaging* / Q000209:etiology / Q000628:therapy; D008297:Male; D008875:Middle Aged; D036542:Tomography, Spiral Computed
chemical_list: D003287:Contrast Media