Extraocular muscles in Graves ophthalmopathy: usefulness of T2 relaxation time measurements.

Abstract

To determine if T2 relaxation time measurements with magnetic resonance (MR) imaging in patients with Graves ophthalmopathy (GO) can predict response to therapy. Studied were 84 patients with GO, 27 with Graves disease without ophthalmopathy (GD), and 12 control subjects without Graves disease. T2 times of extraocular muscles and retrobulbar fat tissue were measured. Twenty-five patients with GO were treated with systemic corticosteroids and retroorbital radiation therapy. T2 relaxation times of muscles in patients with GD were the same as those in controls but were longer in patients with GO (P < .05). T2 times of fat in all patients were the same as those of the controls. The predicted probability of response to treatment increased with increased mean T2 relaxation times of extraocular muscles prior to therapy. Of the 25 patients with combined therapy, only those with particularly prolonged T2 relaxation times showed impressive response. T2 relaxation time measurements with MR allow noninvasive detection of acute muscle inflammation and predict which patients with GO will likely benefit from antiinflammatory therapy.