Tóm tắt
Background: Measurements of extraocular muscle diameter may be useful in diagnosis and as an outcome indicator in the assessment of treatment options in thyroid-associated ophthalmopathy. Racial differences are known to account for craniofacial variations and orbital sizes.
Objective: To determine the normal diameters of extra-ocular muscles using computed tomography in a homogeneous, group of hospital patients in a tertiary hospital in Nigeria.
Material and Method: The maximum diameters of extra-ocular muscles were measured for 182 normal patients on thin slice reconstructed coronal computed tomography images. The effects of age and sex were determined.
Result: Normal ranges for the diameters (mean + 2 SDs) of extraocular muscles were 4.5 + 1.2 mm for medial rectus, 4.9 + 2.1 mm for lateral rectus, 4.8 + 1.6 mm for inferior rectus and 4.0 + 1.5 mm for the superior group. The mean diameter of the extra-ocular muscles of male patients was not significantly larger than that of female patients (p > 0.05). There was a small but positive correlation between age and diameter of each extra-ocular muscle except in the left medial rectus and right lateral rectus muscles (P<0.05).
Conclusion: These normative values may serve as radiological reference values in the assessment of changes in size and suspected enlargement of the extraocular muscles in Nigerian patients. They may also be extrapolated to other Black African patients, until population studies become available.
Keywords: Extra-ocular muscle, Normal measurement, Computed tomography
Résumé
Introduction : Les mesures de diamètre du muscle extra oculaire peuvent être utiles dans le diagnostic et comme un indicateur du résultat dans la répartition des options de traitement de l’ophthalmopathie associée à la thyroïde. Les différences raciale sont connues a expliquer les variations cranio-faciales et dimensions orbitales.
Objective: Pour déterminer les diamètres normaux des muscles extra oculaires en utilisant la tomographie supputée dans un groupe homogène de patients d’hôpital d’un hôpital tertiaire au Nigeria.
Matériel et Méthode: Les diamètres maximum des muscles extra oculaires étaient mesurés pour 182 patients normaux sur des tranches légères reconstruites des images coronales de tomographie supputée. Les effets de l’âge et du sexe étaient déterminés.
Résultats: Les rangs normaux pour les diamètres (moyenne + 2SDs) des muscles extra oculaires étaient 4,5 + 1,2 mm pour le rictus médial, 4,9 + 2,1 pour le rictus latéral, 4,8 + 1,6 pour le rictus inferieur et 4,0 + 1,5 pour le groupe supérieur. Parmi les patients, le diamètre moyen des muscles extra oculaires des hommes n’était de manière significatif plus large que celui des femmes (p>0,05). Il y avait une petite mais positive corrélation entre l’âge et le diamètre de chaque muscle extra oculaire hormis dans les muscles du rictus médial gauche et du rictus latéral droit (p<0,05).
Conclusion: Ces valeurs normatives peuvent servir de valeurs référentielles radiologiques dans la répartition des changements en dimension et agrandissement soupçonné des muscles extra oculaires des patients nigérians. Elles peuvent aussi être extrapolées aux autres patients Africain Noir, jusqu’à ce que des études basées sur la population deviennent disponible.
Mots clés : Muscle extra oculaire, Mesure normal, Tomographie supputée
Correspondence: Dr. Olufunmilola A. Ogun, Department of Ophthalmology, College of Medicine, University of Ibadan, Ibadan, Nigeria. E-mail: olufunmiogun@gmail.com
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