Radiological measurements of lacrimal gland in thyroid eye disease

Lacrimal gland enlargement is a common feature of thyroid eye disease (TED) and has been positively correlated with the clinical activity score. Although lacrimal gland volume is the preferred measure of lacrimal gland size, its calculation is not clinically translatable due to the expertise, time and advanced software required. The aim of our study is to determine whether the lacrimal gland volume in patients with TED undergoing magnetic resonance imaging (MRI) can be estimated using simpler lacrimal gland linear and area measurements.

A retrospective review of 102 orbits (51 patients) with TED who underwent orbital MRI was conducted. The maximum length, width, and area of the lacrimal gland were measured in axial and coronal sections. Lacrimal gland volume was calculated by using a manual segmentation technique on all consecutive axial slices on commercially available software, OsiriX. All quantitative measurements were correlated with the lacrimal gland volume.

Mean age of participants was 59 ± 16 years, and 67% (n = 34) were females. With multivariate analyses, combined lacrimal gland axial and coronal areas strongly correlated with volume (r = 0.843, p < 0.01). Strong univariate predictors of volume included axial area (r = 0.704, p < 0.01) and coronal area (r = 0.722, p < 0.01), while moderate predictors included axial length (r = 0.523, p < 0.01), axial width (r = 0.521, p < 0.01), coronal length (r = 0.450, p < 0.01), and coronal width (r = 0.649, p < 0.01).

In patients with thyroid eye disease, lacrimal gland volume can be estimated using axial and coronal areas, which is simpler and more time efficient than calculating volumes.