Fig. 4

Diffusion-weighted images (DWI) were acquired using the diffusion gradient applied perpendicular to the optic nerves (black arrows), at baseline (a, before EAE induction), time 1 (b, onset of ON in the first eye), and time 2 (c, onset of ON in the second eye) from an representative EAE mouse. Optic nerve swelling was seen at time 1 and 2 caused by inflammation associated increase in cellularity and edema. Significantly increased optic nerve volume was seen after ON (d, p < 0.005). The corresponding DBSI-derived axon volume (optic nerve volume × DBSI fiber fraction) suggested a significant axonal loss in optic nerves (e, p < 0.05 and p < 0.005 for time 1 and 2, respectively). DBSI fiber fraction, reflecting effects of axonal loss and dilution effect of axonal density from inflammation, correlated well with visual acuity (f). One asterisk indicates p < 0.05. Double asterisks indicate p < 0.005