Application and accuracy of spiral CT in the measurement of orbital volume

Objective To investigate the application and accuracy of spiral CT in the measurement of orbital volume. Methods A total of 32 non-ophthalmic patients (64 eyes) admitted to our hospital from September 2016 to October 2018 were selected. Volume Rendering (VR) imaging was performed on the bilateral orbits of all the patients, and the VR detection value level was used as the gold standard for comparison. At the same time, 32 cases and 64 eyes were reconstructed at different thickness/spacing: 2 mm/2 mm, 2 mm/4 mm, 2 mm/5 mm, 3 mm/3 mm and 3 mm/5 mm parameters by spiral CT, and the images were taken screenshots. The measurement level and error rate range of orbital volume of 64 eyes in different thickness/width conditions; Accuracy of orbital volume detection in 64 eyes under different thickness/width conditions. Results During VR detection, the average orbital volume value was (22.9±2.6) cm³. At 2 mm/2 mm, the orbital volume value detected was (22.4±2.3) cm³, which had no significant difference with VR detection value (P>0.05). There was statistically significant difference between orbital volume value level and VR detection value under other thickness/interval parameters (all P<0.05). To take the error rate <5% as the criterion of accuracy evaluation; under the condition of 2 mm/2 mm, the accuracy rate reached 100.0%, followed by 2 mm/4 mm,with the accuracy rate of 89.1%, and the lowest was 3 mm/5 mm, with the accuracy rate of 10.9%. The difference between groups was statistically significant (all P<0.05). Conclusion Spiral CT was used to measure orbital volume when the thickness/interval was set to 2 mm/2 mm, with the minimum error rate. The level of orbital volume can be accurately and objectively measured, and the changes, outcomes and curative effects of related diseases can be evaluated by referring to its level.