[Measurements of ultrasound reflectivity of oculomotor muscles in endocrine orbitopathy]

In the course of Graves' disease (GD) the extraocular muscles become fibrotic after an acute inflammatory stage. Differentiation of these two stages is important for therapy.

First, we examined the eye muscles of 30 healthy volunteers with the 10 MHz-B probe (Ultrascan) Digital B 2000) and then those of 20 patients with GD. The thickness was measured in the longitudinal displayed muscle always with the same gain. The amplitude of the highest inner muscle spikes expressed as a percentage of amplitude of retina-sclera spike provided the internal reflectivity. The stage of GD was determined by clinical signs.

In GD, thickness of inferior and medial rectus was significantly enhanced in both the inflammatory and fibrotic stages, while internal reflectivity was only significantly higher in the latter stage.

Ultrasound discriminates the acute from chronic course of GD in eye muscles and thus provides a very useful tool for making therapeutic decisions.