Although CT imaging of the orbits is preferred, CT imaging of the head may be appropriate if an intracranial abnormality is suspected. Precontrast and postcontrast imaging of the orbits is typically not necessary in evaluating these patients as the precontrast images do not add significant diagnostic information in this scenario. Radiography Orbital or skull radiographs are insufficient to detect pathology in patients presenting with proptosis and have primarily been supplanted by CT. Summary of Recommendations Orbital trauma is best assessed with a noncontrast orbit CT and/or noncontrast CT of the head, which are often complementary. Orbital asymmetry, exophthalmos, or enophthalmos can be evaluated with contrast-enhanced orbit CT or contrast-enhanced orbit MRI, which are often complementary. Contrast-enhanced CT or contrast-enhanced MRI are both appropriate in evaluating orbital cellulitis, uveitis, or scleritis, with CT often performed first during the initial assessment. Optic neuritis is best assessed with a contrast-enhanced MRI of the orbits and contrast-enhanced MRI of the head, which are often performed in conjunction with one another. Although there are references that report on studies with design limitations, 4 well-designed or good-quality studies provide good evidence. Appropriateness Category Names and Definitions Relative Radiation Level Information Potential adverse health effects associated with radiation exposure are an important factor to consider when selecting the appropriate imaging procedure. Because there is a wide range of radiation exposures associated with different diagnostic procedures, a relative radiation level (RRL) indication has been included for each imaging examination. The RRLs are based on effective dose, which is a radiation dose quantity that is used to estimate population total radiation risk associated with an imaging procedure. Patients in the pediatric age group are at Orbits, Vision and Visual Loss
Orbits Vision and Visual Loss. Although CT imaging of the orbits is preferred, CT imaging of the head may be appropriate if an intracranial abnormality is suspected. Precontrast and postcontrast imaging of the orbits is typically not necessary in evaluating these patients as the precontrast images do not add significant diagnostic information in this scenario. Radiography Orbital or skull radiographs are insufficient to detect pathology in patients presenting with proptosis and have primarily been supplanted by CT. Summary of Recommendations Orbital trauma is best assessed with a noncontrast orbit CT and/or noncontrast CT of the head, which are often complementary. Orbital asymmetry, exophthalmos, or enophthalmos can be evaluated with contrast-enhanced orbit CT or contrast-enhanced orbit MRI, which are often complementary. Contrast-enhanced CT or contrast-enhanced MRI are both appropriate in evaluating orbital cellulitis, uveitis, or scleritis, with CT often performed first during the initial assessment. Optic neuritis is best assessed with a contrast-enhanced MRI of the orbits and contrast-enhanced MRI of the head, which are often performed in conjunction with one another. Although there are references that report on studies with design limitations, 4 well-designed or good-quality studies provide good evidence. Appropriateness Category Names and Definitions Relative Radiation Level Information Potential adverse health effects associated with radiation exposure are an important factor to consider when selecting the appropriate imaging procedure. Because there is a wide range of radiation exposures associated with different diagnostic procedures, a relative radiation level (RRL) indication has been included for each imaging examination. The RRLs are based on effective dose, which is a radiation dose quantity that is used to estimate population total radiation risk associated with an imaging procedure. Patients in the pediatric age group are at Orbits, Vision and Visual Loss