Khizar Rana1,2, Valerie Juniat3,4, Aaron Rayan5, Sandy Patel5, Dinesh Selva3,4. 1. Department of Ophthalmology & Visual Sciences, University of Adelaide, North Terrace, Adelaide, South Australia, 5000, Australia. khizar.rana@adelaide.edu.au. 2. South Australian Institute of Ophthalmology, Royal Adelaide Hospital, Port Road, Adelaide, South Australia, 5000, Australia. khizar.rana@adelaide.edu.au. 3. Department of Ophthalmology & Visual Sciences, University of Adelaide, North Terrace, Adelaide, South Australia, 5000, Australia. 4. South Australian Institute of Ophthalmology, Royal Adelaide Hospital, Port Road, Adelaide, South Australia, 5000, Australia. 5. Department of Medical Imaging, Royal Adelaide Hospital, Port Road, Adelaide, South Australia, 5000, Australia.
Abstract
PURPOSE: We describe and compare the normative values of orbital structures in an Australian cohort on T1-weighted MRI and fat-suppressed contrast-enhanced T1-weighted MRI. METHODS: Retrospective review of patients who underwent 3T orbital MRI. The maximum extraocular muscle (EOM) and superior ophthalmic vein (SOV) diameters on normal orbits were recorded. The extraocular muscle diameters were summed to produce the sum of all muscles. RESULTS: The normal measurements (mean ± SD) from 141 orbits that had fat-suppressed contrast-enhanced MRI: medial rectus, 4.1 ± 0.5 mm; lateral rectus (LR), 3.9 ± 0.7 mm; superior muscle group (SMG), 4.5 ± 0.7 mm; inferior rectus (IR), 4.6 ± 0.7 mm; and SOV, 1.8 ± 0.7 mm. The normal measurement from 84 orbits that had T1-weighted MRI: MR, 4.1 ± 0.5 mm; LR, 3.4 ± 0.6 mm; SMG, 4.3 ± 0.7 mm; IR, 4.6 ± 0.7 mm; SOV, 2.0 ± 0.7 mm. Eighty-four orbits had both MRI sequences performed. The LR, SMG and the sum of all muscles were significantly larger on fat-suppressed contrast-enhanced T1-weighted MRI sequence than the T1-weighted sequence (P < 0.01), whereas the SOV was significantly larger on the T1-weighted sequence (P < 0.01). CONCLUSION: These data may aid in diagnosing pathological enlargement of the EOMs and SOV on different scan sequences.
PURPOSE: We describe and compare the normative values of orbital structures in an Australian cohort on T1-weighted MRI and fat-suppressed contrast-enhanced T1-weighted MRI. METHODS: Retrospective review of patients who underwent 3T orbital MRI. The maximum extraocular muscle (EOM) and superior ophthalmic vein (SOV) diameters on normal orbits were recorded. The extraocular muscle diameters were summed to produce the sum of all muscles. RESULTS: The normal measurements (mean ± SD) from 141 orbits that had fat-suppressed contrast-enhanced MRI: medial rectus, 4.1 ± 0.5 mm; lateral rectus (LR), 3.9 ± 0.7 mm; superior muscle group (SMG), 4.5 ± 0.7 mm; inferior rectus (IR), 4.6 ± 0.7 mm; and SOV, 1.8 ± 0.7 mm. The normal measurement from 84 orbits that had T1-weighted MRI: MR, 4.1 ± 0.5 mm; LR, 3.4 ± 0.6 mm; SMG, 4.3 ± 0.7 mm; IR, 4.6 ± 0.7 mm; SOV, 2.0 ± 0.7 mm. Eighty-four orbits had both MRI sequences performed. The LR, SMG and the sum of all muscles were significantly larger on fat-suppressed contrast-enhanced T1-weighted MRI sequence than the T1-weighted sequence (P < 0.01), whereas the SOV was significantly larger on the T1-weighted sequence (P < 0.01). CONCLUSION: These data may aid in diagnosing pathological enlargement of the EOMs and SOV on different scan sequences.
Authors: Christopher R Adam; Carol L Shields; Justin Gutman; H Joon Kim; Brent Hayek; John W Shore; Alexandra Braunstein; Flora Levin; Bryan J Winn; Ivan Vrcek; Ronald Mancini; Craig Linden; Christina Choe; Mithra Gonzalez; David Altschul; Santiago Ortega-Gutierrez; Srinivasan Paramasivam; Johanna T Fifi; Alejandro Berenstein; Vikram Durairaj; Roman Shinder Journal: Ophthalmic Plast Reconstr Surg Date: 2018 Jan/Feb Impact factor: 1.746