This includes lesions intrinsic to the nerve, such as an optic nerve glioma, or extrinsic to the nerve resulting in mass effect, such as an optic nerve sheath meningioma. The differential diagnosis varies based on the age of the patient. MRI MRI provides excellent soft-tissue resolution of structures within the orbit, including the globe, muscles, tendons, nerves, and vascular structures. MRI of the orbits without and with contrast is the preferred modality in evaluating soft-tissue pathology within and around the orbit, particularly in mass characterization, optic nerve pathology, and assessing disease within the globe and orbit [1,7,58]. If contrast cannot be given, a noncontrast orbit MR may still provide useful information. If there is a significant intracranial component, additional MRI of the brain without and with contrast may be indicated to evaluate for intracranial spread of disease. CT CT is superior to MRI for foreign body assessment, calcification detection, and osseous evaluation [43]. Orbital CT is complementary to MRI in evaluating patients with ocular, orbital, and skull base neoplasms. In patients presenting with clinical suspicion for an intraorbital mass lesion, orbital CT with contrast may be complementary to MRI in providing additional information about adjacent bone involvement, including bone erosion, sclerosis, or periosteal reaction that may not be readily seen with MRI [2,7]. If contrast cannot be given, a noncontrast orbit CT may still add useful information. CT imaging of the head with contrast may also be appropriate if more extensive skull or skull-base involvement is suspected. Precontrast and postcontrast orbital imaging is typically not necessary in evaluating these patients as the precontrast images do not add significant diagnostic information in this scenario. CTA, MRA, Arteriography CTA or MRA are complementary and may be added to routine CT or MRI scans if there is a suspicion for an intraorbital vascular lesion [35,36].
Orbits Vision and Visual Loss. This includes lesions intrinsic to the nerve, such as an optic nerve glioma, or extrinsic to the nerve resulting in mass effect, such as an optic nerve sheath meningioma. The differential diagnosis varies based on the age of the patient. MRI MRI provides excellent soft-tissue resolution of structures within the orbit, including the globe, muscles, tendons, nerves, and vascular structures. MRI of the orbits without and with contrast is the preferred modality in evaluating soft-tissue pathology within and around the orbit, particularly in mass characterization, optic nerve pathology, and assessing disease within the globe and orbit [1,7,58]. If contrast cannot be given, a noncontrast orbit MR may still provide useful information. If there is a significant intracranial component, additional MRI of the brain without and with contrast may be indicated to evaluate for intracranial spread of disease. CT CT is superior to MRI for foreign body assessment, calcification detection, and osseous evaluation [43]. Orbital CT is complementary to MRI in evaluating patients with ocular, orbital, and skull base neoplasms. In patients presenting with clinical suspicion for an intraorbital mass lesion, orbital CT with contrast may be complementary to MRI in providing additional information about adjacent bone involvement, including bone erosion, sclerosis, or periosteal reaction that may not be readily seen with MRI [2,7]. If contrast cannot be given, a noncontrast orbit CT may still add useful information. CT imaging of the head with contrast may also be appropriate if more extensive skull or skull-base involvement is suspected. Precontrast and postcontrast orbital imaging is typically not necessary in evaluating these patients as the precontrast images do not add significant diagnostic information in this scenario. CTA, MRA, Arteriography CTA or MRA are complementary and may be added to routine CT or MRI scans if there is a suspicion for an intraorbital vascular lesion [35,36].