Features of bacterial orbital cellulitis on MRI imaging
Reviewed by Su Young

This multi-centre retrospective study from Australia and the UK examined the quantitative and qualitive parameters of magnetic resonance imaging (MRI) imaging in bacterial orbital cellulitis. Twenty MRI scans from 20 patients with pre-septal and orbital fat involvement (mean age: 40.8 ±24.3 years, M:F = 15:5) between 2011 and 2022 were analysed. Three (15%) paediatric (<18 years) cases were included. The extraocular muscles (EOM) were affected in 19 cases, with the superior muscle complex (18/19, 94.7%) most commonly affected. Mean enlargement ratio (1.30, range: 1.04–1.82) was greatest for the medial rectus on axial views on T1 and fat-suppressed contrast-enhanced T1. Optic peri-neuritis was present in 11 (55.0%) patients, whilst two (9.5%) cases had optic neuritis. A greater degree of proptosis was observed in patients with optic neuropathy and those who underwent surgical intervention compared to those without (p=0.002 and p=0.002, respectively). Adjacent paranasal sinus disease was observed in 15 (75%) patients, and intracranial extension was noted 12 (60%) patients, with one case of superior sagittal sinus thrombosis. To conclude, the authors report that simple quantitative parameters, such as proptosis and EOM measurements, correlate with high-risk clinical features and may have utility in predicting clinical course. For eye practitioners, an understanding of MRI prognostic features for orbital cellulitis will guide early treatment escalation in this rare but potentially deadly disease.

Qualitative and quantitative magnetic resonance imaging in bacterial orbital cellulitis.
Ang T, Tong JY, Patel S, et al.
SEMINARS IN OPHTHALMOLOGY
2024;39(8):628–33.