Normative Measurement of Orbital Structures in Computed Tomography

Authors

  • Damodar Rokka Departement of Radiology, National Trauma Center, National Academy of Medical Sciences (NAMS), Kathmandu
  • Sharma Poudel Department of Radiology, Maharajgunj Medical Campus, Tribhuvan University Teaching Hospital, Institute of Medicine, Kathmandu
  • Prakash Kayastha Department of Radiology, Maharajgunj Medical Campus, Tribhuvan University Teaching Hospital, Institute of Medicine, Kathmandu
  • Sundar Suwal Department of Radiology, Maharajgunj Medical Campus, Tribhuvan University Teaching Hospital, Institute of Medicine, Kathmandu
  • Sudil Poudyal Department of Radiology, Chitwan Medical College, Chitwan
  • Saroj Chhetry Department of Radiology, Sahid Gangalal National Heart Center, Kathmandu
  • Benu Lohani Department of Radiology, Maharajgunj Medical Campus, Tribhuvan University Teaching Hospital, Institute of Medicine, Kathmandu
  • Shantalall Shrestha Department of Radiology, Maharajgunj Medical Campus, Tribhuvan University Teaching Hospital, Institute of Medicine, Kathmandu
  • Rakesh Karn Department of Radiology, Grande International Hospital, Kathmandu

Keywords:

CT, measurements, orbit

Abstract

Introduction
Normal orbital dimensions are important for diagnosing orbital pathologies. Computed tomography (CT) of the orbit is an important modality offering high accuracy for precise measurements of orbit. The study was disbursed to ascertain criteria for the normative values of the various orbital dimensions using computed tomography in patients visiting Tribhuvan University Teaching Hospital, Kathmandu.

Methods
Orbital volume, ocular diameter, length of the interzygomatic line (IZL), the distance of the posterior extent of the globe from the interzygomatic line, globe position, diameters of extraocular muscles (medial, lateral, superior group, and inferior rectus) and lens density were measured in each eye of 172 patients undergoing CT examination of paranasal sinuses. The correlations with age and sex were also analyzed.

Results
Mean values (mean±SD) of orbital volume, ocular diameter, IZL, globe position and lens density were 24.54±2.57 cm3, 2.44±0.22 cm, 94.3±6.2 mm, 12.3±2.4 mm and 141.43±16.62 HU respectively. Mean diameters of extraocular muscles were 3.67± 0.52 mm, 3.36± 0.50 mm, 3.74±0.42 mm and 3.87±0.38 mm for medial rectus, lateral rectus, inferior rectus and the superior group respectively. There was no significant age and gender difference in most of the measurements. There was significant positive correlation of age with lens density, orbital volume and ocular diameter (p<0.05).

Conclusion
Normative data of different orbital measurements were obtained. The present result may help radiologists and ophthalmologists to accurately assess various orbital parameters, particularly in Nepalese populations.

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Published

2021-07-20

How to Cite

Rokka, D., Poudel, S., Kayastha, P., Suwal, S., Poudyal, S., Chhetry, S., Lohani, B., Shrestha, S., & Karn, R. (2021). Normative Measurement of Orbital Structures in Computed Tomography. Journal of Institute of Medicine Nepal, 42(3), 42–46. Retrieved from http://www.jiomnepal.com.np/index.php/jiomnepal/article/view/44