FIG. 4.

Magnetization transfer magnetic resonance imaging (MT-MRI) is a noninvasive technique that can be used to quantify pathological changes in the injured cervical cord in vivo. (A) Mid-sagittal section of an uninjured cord pseudocolored to represent magnetization transfer ratios (MTRs). (B) Mid-sagittal section through the injury epicenter at 2 weeks post-injury. (C) Mid-sagittal section through the injury epicenter at 4 weeks post-injury. (D) Mid-sagittal section through the injury epicenter at 8 weeks post-injury. (E) Quantification of MTR over the recovery period shows a significant difference in MTR between three different regions in the injured cord (epicenter, rim of WM surrounding the epicenter, and WM distal to the injury), but no significant difference in the MTR of any of these regions over time (two-way analysis of variance with Tukey's post-hoc test; n=3 in each time point postinjury; p<0.05). Single asterisks indicate when MTR is significantly different from epicenter. Two asterisks indicate a significant difference between the rim of WM surrounding the epicenter and distal WM. Δ indicates that, at 4 weeks postinjury, there was a significant difference between the MTRs of WM in the injured (yellow bar) and uninjured cord (gray bar); n=3 in uninjured group; t-test; p=0.033). WM, white matter; SCI, spinal cord injury. Color image is available online at www.liebertpub.com/neu