Calculated CT volumes of lacrimal glands in normal Caucasian orbits.

INTRODUCTION: The objective was to describe the range of normal volumes for the lacrimal gland calculated from CT. METHODS: A retrospective review with institutional review board approval of 293 CT scans of 586 orbits was performed. Patients were included if they were Caucasian and aged 18 years or older. Orbits were excluded if there was a disease or trauma. OsiriX software was used to outline the lacrimal gland in consecutive axial slices and to calculate the volume. Inter-rater agreement was assessed in a subset of 30 randomly selected orbits by observers of different levels of training using the intraclass correlation coefficient (ICC). RESULTS: Two hundred sixty orbits of 187 patients were included. The mean volume of the lacrimal gland was 0.696 cm2 in right orbits (SD = 0.261) and 0.649 cm2 in left orbits (SD = 0.231), with no significant difference between right and left (p= 0.125). The mean volume was 0.680 cm2 in men (SD = 0.241) and 0.662 cm2 in women (SD = 0.260), with no significant difference between men and women (p = 0.564). There was an inverse relationship between gland volume and age (Pearson r= -0.428 right orbits and -0.469 left orbits). Of the 73 bilateral patients, right and left orbits correlated well (Pearson r = 0.712). Agreement was good among the observers (ICC = 0.727). CONCLUSIONS: This is the first study to report the range of normal volume for Caucasian lacrimal glands measured on CT scans. The volume of the lacrimal gland decreases with age, and there is no gender or laterality difference.