Normal anatomy and lesions of the lacrimal sac and duct: evaluated by dacryocystography, computed tomography, and MR imaging.

Diseases of the lacrimal system are optimally evaluated by dacryocystography, CT, MR imaging, and nuclear scintigraphy. Dacryocystography is selected to define the lumen of the lacrimal drainage system in inflammatory disease (dacryocystitis), dacryoceles, dacryoliths, and developmental abnormalities. Dacryocystography provides supplemental information in benign and malignant tumors, principally to differentiate an intrinsic lesion from an extrinsic lesion. CT is indicated for delineation of palpable mass lesions such as cysts, benign and malignant tumors, and diseases, especially in the paranasal sinuses, affecting the lacrimal apparatus secondarily. MR imaging has limited application but is useful to differentiate fluid from solid masses within the sac and to define tumor extension from the sac into the duct and anatomic regions outside the sac and duct. MR imaging with gadolinium enhancement should be used in suspected tumors and to separate a cyst from a solid mass. Radiologic methods fail to identify the histopathology of benign and malignant tumors. Nuclear scintigraphy is helpful in patients with epiphora with no demonstrable anatomic abnormality on dacryocystography.