Computer tomography of the lacrimal drainage system and lacrimal pathway obstruction

Objective To observe the CT manifestations of the normal lacrimal drainage system and lacrimal pathway obstruction.Methods CT pictures of 32 cases with normal lacrimal drainage, and 19 cases with lacrimal pathway obstruction were reviewed and analyzed.Results Of the 32 cases with normal drainage, 78.1% of the lacrimal sac could be identified, and 21.9% could not be identified. All nasolacrimal ducts could be clearly displayed with axial computer tomography. Gas may be present in normal lacrimal sacs and ducts that had been identified, or soft tissue may be present in the images. High density mass and the expansion of the lacrimal sac and nasolacrimal duct were observed in four CT pictures of neoplasia. Higher tissue density and bony pieces in the lacrimal sac area, fractures and obstruction of the nasolacrimal duct were found in 9 cases with trauma. Thickened soft tissue and higher density in the lacrimal sac area and nasolacrimal duct opacity were seen in 6 cases with dacryocystitis and sinusitis.Conclusion Axial computer tomography can display a majority of the lacrimal sacs and all nasolacrimal ducts. Normal lacrimal sacs and ducts may have air or soft tissue present in the image. Neoplasia, trauma and inflammation of the lacrimal sac and nasolacrimal duct can be clearly displayed with CT scans.