Click on image to view larger version.
Fig 4. Sagittal in vivo MR imaging scans of contused rat spinal cord and corresponding histology. In vivo MR imaging in adult rats at 2 and 8 weeks after thoracic contusion injury displays signal intensity changes, which parallel the ex vivo MR imaging data (2D multisection gradient-echo; A–C, section thickness, 311 µm; FOV, 30 x 30 mm; in-plane resolution, 117 x 117 µm; TE, 4.4 milliseconds; TR, 
200 milliseconds, depending on heart rate; D–F, section thickness, 300 µm; FOV, 40 x 25 mm; in-plane resolution, 156 x 98 µm; TE, 3.7 milliseconds; TR, 200 milliseconds, depending on heart rate). Scale bar A–F, 5 mm; G–O, 1 mm. Consecutive sagittal MR images are shown at 2 weeks (A–C) and 8 weeks (D–F) postinjury with corresponding histologic Nissl (G–I) and Prussian-blue (J–L) –stained sections, and sections processed for ED1 immunohistochemistry (macrophages, monocytes; M–O), all from the same animal. Arrows in A and B highlight the site of the impact. Hypointensities along ascending and descending axon projections in the dorsal columns (B and E) correlate with hemosiderin deposits (K) rather than macrophage/monocyte infiltration (O; respective areas are indicated by arrowheads). These changes increase from 2 weeks (C) until 8 weeks (G) postinjury. The clear reduction in cord diameter over time (B vs E and C vs F) corresponds to the atrophy seen in histologic sections (G–O).
