In the present study, the adult Omani patients (aged ≥18 years) who had visited the Department of Radiology and Molecular Imaging at the Sultan Qaboos University Hospital, Muscat, Oman, were studied retrospectively using an electronic medical records database (TrakCare Unified Health Information System). All the consecutive patients of either gender aged ≥18 years who had been referred for a CT scan of the brain from 1 January 2019 to 31 March 2019 were included. After applying the inclusion and exclusion criteria, there were 273 Omani patients. Patients with orbital fractures and ocular or facial surgery or deformity were excluded. Additionally, scans with motion artifacts or incomplete coverage of the orbits and those performed for non-Omani patients were also excluded from the study sample.
All the CT scans were performed as per the routine standard protocol for non-enhanced CT of the brain using 64 slice multidetector CT (Siemens Sensation 64, Siemens AG, Munich, Germany) with a kilovoltage peak of 120 kV and tube current modulation. The images and measurements were assessed using the Synapse Radiology PACS, Version 5.7.102 (Synapse® Enterprise Imaging, Fujifilm Worldwide, Tokyo, Japan).
The measurements were performed using the reconstructed thin slices of 1.2 mm in the bone window. A window width/level of 2000/500 mm was used while screening the images. The following measurements were performed for every subject: the interorbital distance, interzygomatic distance (IZD), horizontal orbital diameter and vertical orbital diameter. First, the orientation of the axial images was adjusted according to the Frankfort horizontal plane, which is defined as the line from the highest point of the opening of the external auditory canal to the lower margin of the orbital rim.16 (link) After adjusting the axial plane, the IOD was measured as the minimal distance between the medial orbital walls. The IZD was determined as the maximum distance between the anterior aspects of the zygomatic arches [Figure 1 ]. The horizontal distance of orbit (HDO) was measured as the maximum distance from the anterior lacrimal crest to the lateral orbital wall [Figure 2A ]. The vertical distance of orbit (VDO) was performed in the sagittal plane after adjusting the angulation of the sagittal image along the long axis of the orbit and measured as the maximum distance between the frontal and the maxillary bones [Figure 2B ]. Finally, OI was calculated using the following formula:
Statistical Package for the Social Sciences (SPSS), version 23.0 (IBM Corporation, Armonk, New York, USA) was used to analyse the data. The data were presented as mean and standard deviation. Independent sample t-test was used to determine the associations between the orbital dimensions and gender, while paired t-test was used to determine the laterality difference. The association between the orbital dimensions and age groups were determined using one-way analysis of variance (ANOVA). The differences were considered significant at P value <0.05.
The study was conducted after receiving ethical approval from the Medical Research Ethics Committee at the Sultan Qaboos University Hospital (#SQU-EC/445/2021).
All the CT scans were performed as per the routine standard protocol for non-enhanced CT of the brain using 64 slice multidetector CT (Siemens Sensation 64, Siemens AG, Munich, Germany) with a kilovoltage peak of 120 kV and tube current modulation. The images and measurements were assessed using the Synapse Radiology PACS, Version 5.7.102 (Synapse® Enterprise Imaging, Fujifilm Worldwide, Tokyo, Japan).
The measurements were performed using the reconstructed thin slices of 1.2 mm in the bone window. A window width/level of 2000/500 mm was used while screening the images. The following measurements were performed for every subject: the interorbital distance, interzygomatic distance (IZD), horizontal orbital diameter and vertical orbital diameter. First, the orientation of the axial images was adjusted according to the Frankfort horizontal plane, which is defined as the line from the highest point of the opening of the external auditory canal to the lower margin of the orbital rim.16 (link) After adjusting the axial plane, the IOD was measured as the minimal distance between the medial orbital walls. The IZD was determined as the maximum distance between the anterior aspects of the zygomatic arches [
Statistical Package for the Social Sciences (SPSS), version 23.0 (IBM Corporation, Armonk, New York, USA) was used to analyse the data. The data were presented as mean and standard deviation. Independent sample t-test was used to determine the associations between the orbital dimensions and gender, while paired t-test was used to determine the laterality difference. The association between the orbital dimensions and age groups were determined using one-way analysis of variance (ANOVA). The differences were considered significant at P value <0.05.
The study was conducted after receiving ethical approval from the Medical Research Ethics Committee at the Sultan Qaboos University Hospital (#SQU-EC/445/2021).
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