Evaluation of extraocular muscles in the edematous phase of Graves ophthalmopathy on contrast-enhanced fat-suppressed magnetic resonance imaging.

摘要

OBJECTIVE: Extraocular muscles (EOMs) reveal characteristic contrast-enhancement patterns on magnetic resonance (MR) imaging due to their rich vascular supply. The objective of this study was to evaluate contrast-enhancement patterns of EOMs in patients with edematous phase of Graves ophthalmopathy (GO) using contrast-enhanced fat-suppressed MR imaging in comparison with normal volunteers. METHODS: EOMs of 15 patients with edematous phase of GO and those of 15 normal volunteers were evaluated using coronal T1-weighted MR images with fat suppression before and after intravenous administration of gadolinium. The image sequence was a fast spin-echo with chemical shift selective fat saturation. The degree of contrast enhancement for EOMs and temporal muscles (TMs) was assessed via a 4-step grading system and by 2 reviewers. RESULTS: There were statistically significant differences for the degrees of contrast enhancement in all EOMs between the patients with GO and normal volunteers. The degrees of contrastenhancement for all EOMs were significantly decreased in patients with edematous phase of GO. CONCLUSIONS: The microcirculation within the EOMs tends to be impaired during the progress of disease, and the MR imaging pattern gives a semiquantitative measurement of the microcirculatory impairment of the EOMs during the edematous phase of the disease.