Normative Measurements of the Chinese Extraocular Musculature by High-Field Magnetic Resonance Imaging

作者：Shen Sunny; Fong Kee Siew; Wong Hwee Bee; Looi Audrey; Chan Ling Ling; Rootman Jack; Seah Lay Leng^*

来源：Investigative Ophthalmology & Visual Science, 2010, 51(2): 631-636.

DOI：10.1167/iovs.09-3614

PURPOSE. To establish the normal measurements of diameter and cross-sectional area of the Chinese extraocular muscles (EOMs) and optic nerve-sheath complex (ON) as seen on high-field (3-Tesla; 3T) magnetic resonance imaging (MRI).
METHODS. Coronal 3T MRI of the orbit (TR, 700 ms; TE, 15 ms; FOV, 160 mm; matrix, 256 X 256; slice thickness, 1 mm; and slice gap, 0) was performed on 80 normal Chinese volunteers. T1-weighted images were analyzed with computer-assisted segmentation. The diameter and the cross-sectional area of EOMs and the ON were measured from the image plane at the posterior aspect of the globe and at 7 mm behind the globe. The maximum diameter of EOM was measured from their respective reconstructed images.
RESULTS. The normal measurement (mean +/- SD) of diameter at the posterior aspect of the globe: medial rectus (MR), 3.6 +/- 0.4 mm; inferior rectus (IR), 3.7 +/- 0.8 mm; lateral rectus (LR), 2.3 +/- 0.5 mm; superior oblique (SO), 2.4 +/- 0.6 mm; and the ON, 5.4 +/- 0.7 mm. The normal measurement of diameter 7 mm behind the globe: MR, 3.2 +/- 0.6 mm; IR, 3.9 +/- 0.8 mm; LR, 4.0 +/- 0.8 mm; SO, 2.2 +/- 0.7 mm; and ON, 4.2 +/- 0.5 mm. The normal measurement of cross-sectional area at the posterior aspect of the globe: superior muscle group (SMG), 28.2 +/- 6.5 mm(2); MR, 25.5 +/- 3.2 mm(2); IR, 26.9 +/- 7.2 mm(2); LR, 17.3 +/- 3.9 mm(2); SO, 10.5 +/- 3.5 mm(2); and ON, 27.6 +/- 6.1 mm(2). The normal measurement of cross-sectional area 7 mm behind the globe: SMG, 24.1 +/- 6.6 mm(2); MR, 19.1 +/- 4.6 mm(2); IR, 29.5 +/- 6.6 mm(2); LR, 32.3 +/- 6.5 mm(2); SO, 9.7 +/- 3.9 mm(2); and ON, 17.1 +/- 2.9 mm(2). The normal measurement of maximum diameter: SMG, 4.8 +/- 1.1 mm; MR, 5.1 +/- 0.9 mm; IR, 5.4 +/- 1.0 mm; and LR, 4.5 +/- 0.9 mm.
CONCLUSIONS. The Chinese 3T MRI EOMs and ON normative data may be useful in determining pathologic enlargement of the EOMs and ON in various orbital conditions. (ClinicalTrials. gov number, NCT00348413.) (Invest Ophthalmol Vis Sci. 2010; 51: 631-636) DOI: 10.1167/iovs.09-3614

• 出版日期2010-2