Assessment of lacrimal glands in thyroid eye disease with diffusion-weighted magnetic resonance imaging

Abstract

Purpose: To assess the lacrimal glands in patients with thyroid eye disease with diffusion-weighted magnetic resonance (MR) imaging.

Material and methods: This study was carried out on 44 consecutive patients (17 males, 27 females, with mean age 36 years) with thyroid eye disease and 20 age- and sex-matched volunteers. They underwent diffusion-weighted MR imaging of the orbit. The apparent diffusion coefficient (ADC) values of the lacrimal glands were calculated and correlated with the clinical activity score (CAS).

Results: The mean ADC of lacrimal glands in thyroid eye disease (1.73 × 10^-3 mm²/s) was significantly higher (p = 0.001) than that of volunteers (1.52 × 10^-3 mm²/s). The cutoff ADC value of lacrimal gland used for differentiation of thyroid eye disease from volunteers was 1.62 × 10^-3 mm²/s with an area under the curve value of 0.95 and an accuracy of 96%. There was significant difference (p = 0.03) in the ADC of the lacrimal glands in patients with active (n = 24) and inactive (n = 20) disease. The cutoff ADC value of the lacrimal gland used to suspect active disease was 1.76 × 10^-3 mm²/s with an area under the curve value of 0.80 and an accuracy of 82%. There was positive correlation between the ADC value of the lacrimal glands and CAS (r = 0.73, p = 0.001).

Conclusions: The ADC of the lacrimal glands is a non-invasive imaging parameter that can be used for diagnosis of thyroid eye disease and to predict the active form of the disease.

Keywords: MR imaging; diffusion; lacrimal gland; thyroid eye disease.

Figure 1

Region of interest (ROI) localisation: apparent diffusion coefficient (ADC) map shows ROI localisation of lacrimal gland

Figure 2

Receiver operating characteristic (ROC) curve: A) The cutoff apparent diffusion coefficient (ADC) value of the lacrimal gland used for differentiation of thyroid eye disease from volunteers is 1.62 × 10–3 mm2/s with AUC of 0.95 and accuracy of 96%. B) The cutoff value of ADC value of the lacrimal gland used to predict active thyroid eye disease is 1.76 × 10–3 mm2/s with AUC of 0.80 and an accuracy of 82%