Normal Lacrimal Gland Volumes by Magnetic Resonance Imaging and the Relationship of Lacrimal Gland Volume to Orbital Size.

The aim of this study was to measure volumes of normal lacrimal glands (LGs) using magnetic resonance imaging in African-Americans (AAs) and whites and to evaluate relationships of LG volumes to demographic factors. A retrospective chart review was performed searching for "optic neuropathy" and "optic neuritis," cross-referencing patients who had orbital MRI with and without contrast. Cases were excluded with known history of orbital trauma or surgery, previous diagnoses known to affect LG size, and poor image quality. LGs were outlined in consecutive axial and coronal slices, and volumes were generated using OsiriX software; cross-sectional area of the orbit was measured by outlining the bony orbit in largest axial section. One hundred orbits from 50 patients were included (26 AAs, 24 whites). Mean LG volumes as measured in coronal and axial section were 0.714 and 0.671 cm, respectively; mean orbital area was 10.42 cm. Axial orbital size was found to be highly correlated (P < 0.01) with LG volume. No significant correlation was found with LG volume and age, sex, race, or laterality. This article presents normal values for LG volumes by MRI of AAs and whites. LG volumes were highly correlated with orbital size, a relationship which has not been explored in the recent literature. Such an assessment of LG size relative to patients' orbital dimensions may be more clinically useful than comparison to population-based measures of normal LG volume alone. We found no statistically significant relationship between LG volume and race, sex, age, or laterality.