Correlation Between Optical Coherence Tomography and Magnetic Resonance Imaging of Rectus Muscle Thickness Measurements in Graves' Ophthalmopathy.

Purpose: To assess the correlation between optical coherence tomography (OCT) and magnetic resonance imaging (MRI) measurements of extraocular rectus muscle thickness in patients with Graves' ophthalmopathy.

Methods: This was a cross-sectional observational study conducted in 62 eyes of 31 patients with Graves' ophthalmopathy. The disease phase was inactive in 20 patients and active in the remaining 11. The OCT measurements obtained were: medial rectus thickness at 7.2 and 9.2 mm from the limbus and lateral rectus thickness at 8.5 mm from the limbus. MRI measurements were maximum transversal diameter (T-MRI), craniocaudal diameter (CC-MRI), and muscle area (A-MRI).

Results: For the whole patient cohort, correlation emerged between the OCT-MR and T-MRI measurements (R = 0.428 to 0.576; P ≤ .002), A-MRI (R = 0.562 to 0.674; P < .001), and CC-MRI (R = 0.286 to 0.293; P ≤ .046). In patients with clinically active Graves' ophthalmopathy, correlations with T-MRI (R = 0.576 to 0.604; P ≤ .010) and A-MRI (R = 0.678 to 0.706; P < .001) were higher. No correlations were detected between OCT and MRI measurements of lateral rectus thickness (P ≥ .177), regardless of disease phase.

Conclusions: The correlations observed suggest OCT could be a complementary assessment or screening method to detect thickening of the anterior portion of the medial rectus muscle in patients with Graves' ophthalmopathy, which may be especially useful when MRI is not available. [J Pediatr Ophthalmol Strabismus. 2019;56(5):319-326.].