What is the imaging modality of choice when orbital cellulitis is suspected?

What is the imaging modality of choice when orbital cellulitis is suspected?

• A. Ultrasound of the orbits
• B. Orbital CT
• C. MRI of the orbits
• D. Plain radiographs of the orbits

Answer: (B)

In suspected orbital cellulitis, quickly confirming infection and outlining its extent is essential to prevent vision loss and guide treatment. A contrast-enhanced CT scan of the orbits and sinuses is preferred because it rapidly shows both orbital involvement and sinus disease, helps distinguish orbital cellulitis from preseptal cellulitis, and can reveal important complications such as subperiosteal or intraorbital abscess, as well as bony wall involvement. This information is crucial for deciding on medical therapy versus surgical drainage and for assessing risk of intracranial spread. While MRI offers superior soft-tissue detail and is useful when intracranial extension or optic nerve involvement is suspected, it is slower, less accessible emergently, and not as practical in unstable patients. Ultrasound has limited utility for deep orbital processes due to bone, and plain radiographs are insensitive for orbital infections. Therefore, contrast-enhanced orbital CT best fulfills the needs of rapid, comprehensive evaluation in this setting.

In suspected orbital cellulitis, quickly confirming infection and outlining its extent is essential to prevent vision loss and guide treatment. A contrast-enhanced CT scan of the orbits and sinuses is preferred because it rapidly shows both orbital involvement and sinus disease, helps distinguish orbital cellulitis from preseptal cellulitis, and can reveal important complications such as subperiosteal or intraorbital abscess, as well as bony wall involvement. This information is crucial for deciding on medical therapy versus surgical drainage and for assessing risk of intracranial spread. While MRI offers superior soft-tissue detail and is useful when intracranial extension or optic nerve involvement is suspected, it is slower, less accessible emergently, and not as practical in unstable patients. Ultrasound has limited utility for deep orbital processes due to bone, and plain radiographs are insensitive for orbital infections. Therefore, contrast-enhanced orbital CT best fulfills the needs of rapid, comprehensive evaluation in this setting.