Two patients (68 and 71 years, both female) with sight threatening, active Graves orbitopathy but low clinical activity score underwent MRI scans before and after intravenous corticosteroid treatment. Two MRI techniques, short-term inversion recovery and nonechoplanar diffusion-weighted imaging, were used. Apparent diffusion coefficient values reduced in patient 1 who had successful medical treatment and remained elevated in patient 2 who had an inadequate treatment response. Nonechoplanar diffusion-weighted imaging provided a quantitative measure of treatment response by calculation of the apparent diffusion coefficient. The novel use of nonechoplanar diffusion-weighted imaging for monitoring treatment response in Graves orbitopathy is illustrated but requires further validation.