Artifact from Incomplete Orbital Fat Suppression on Magnetic Resonance Imaging

Orbital fat has short relaxation times that results in a hyperintense appearance on T1-weighted magnetic resonance imaging (MRI). Fat suppressed T1 MRI sequences are needed to remove the fat signal and better visualize the orbital anatomy, including the optic nerve. Contrast can be used with fat suppressed MRI sequences to identify active inflammation within the orbits. Incomplete fat suppression results in asymmetric artefactual hyperintensity within the orbit and does not represent true pathology. To determine whether asymmetric orbital hyperintensity represents artifact or disease, the clinician must view different slice orientations and correlate imaging with clinical findings.