Fig 1.
Study population.
Fig 2.
A. The measurement of the optic nerve sheath diameter on axial noncontrast CT scan at a point where the ophthalmic vein (thin white arrow) crosses the optic nerve (thick white arrow). B. Coronal images used as reference. The white arrow shows the ophthalmic vein crossing the optic nerve.
Fig 3.
ETD measurement in the same patient as in Fig 1.
ETD is measured from retina to retina on axial images. Usually the largest ETD and the ONSD are located in different horizontal planes and are measured on different slices.
Table 1.
Population demographic characteristics according to study groups.
Fig 4.
Gender distribution in study groups.
A significant female predominance in patients with papilledema (study group 2) comparing to the group without papilledema (study group 1) and control group (76%, 40.5% and 51.1% respectively, p = 0.04).
Table 2.
Median and IQR values of ONSD/ETD index according to clinical groups.
Fig 5.
ONSD/ETD index according to clinical groups with corresponding p-values.
ONSD/ETD index is significantly higher (p<0.001) in patients with papilledema (median 0.24, IQR = 0.22–0.25) compared to patients in with no signs of papilledema (median 0.18, IQR = 0.16–0.19) and control group (median 0.17, IQR = 0.15–0.18). There is no significant difference between the control group and patients with no signs of papilledema (p = 0.052).
Fig 6.
Receiver operator characteristic curve at different thresholds of ONSD/ETD index.