Orbital Imaging

CT is often the first imaging method of choice in suspected orbital pathology due to wide availability. Pre- and post-contrast T1-weighted (T1w) and T2-weighted (T2w) images with and without fat suppression are the main structural MRI sequences used in orbital imaging. Functional methods include diffusion-weighted-imaging (DWI) and perfusion imaging techniques with or without intravenous contrast-administration. Restricted diffusion is commonly found in ischemia and in highly cellular lesions such as lymphoma and meningioma. Positron emission tomography (PET) can be used for evaluating systemic disease, such as malignancy, sarcoidosis or IgG4-related disease. Lymphoma can often be distinguished from inflammatory disease based on DWI-derived ADC values.