Correlation between optic nerve sheath diameter measured on imaging with acute pathologies found on computed tomography of trauma patients.

PURPOSE: To evaluate the correlation between optic nerve sheath diameter (ONSD) measurement with signs of increased intracranial pressure (ICP) found on computed tomography (CT) in trauma patients.

MATERIALS AND

METHODS

271 consecutive head CT trauma scans performed at our trauma center were retrospectively reviewed for ONSD and CT findings. Measurement of ONSD was made at CT and, when available, with ultrasonography (US). Imaging signs of increased ICP were assessed. Association between ONSD and signs of ICP were analyzed.

RESULTS

The mean ONSD on axial CT images, optic-nerve axial plane and US was 4.70 ± 0.59 mm, 4.78 ± 0.59 mm, and 3.16 ± 0.50 mm, respectively. The ONSD measured at CT was significantly higher than that measured by US(p < 0.01). No difference of ONSD measured at CT between axial and optic-nerve axial planes. Patients with CT evidence of increased ICP had significantly higher ONSD than those without imaging abnormalities (p = 0.0001-0.0064). The ONSD cutoff points for suggesting increased ICP were 4.8 mm (60.5 % sensitivity, 61.2 % specificity, 20.4 % PPV, 90.4 % NPV) at CT and 3.15 mm (97.4 % sensitivity, 13.8 % specificity, 15.7 % PPV, 97 % NPV) at US.

CONCLUSION

There was a significant association between ONSD and imaging signs of increased ICP in CT with a high NPV. No difference of ONSD measurement at CT between normal and optic-nerve axial planes was observed, whereas there was a significant difference between diameter obtained at CT and US.