Real-Time and Spatial Quantifi cation Using Contrast-Enhanced Ultrasonography of Spinal Cord Perfusion During Experimental Spinal Cord Injury

Study Design. Experimental study in male Wistar rats. Objective. To quantify temporal and spatial changes simultaneously in spinal cord blood flow and hemorrhage during the first hour after spinal cord injury (SCI), using contrast-enhanced ultrasonography (CEU). Summary of Background Data. Post-traumatic ischemia and hemorrhage worsen the primary lesions induced by SCI. Previous studies did not simultaneously assess temporal and spatial changes in spinal cord blood flow. Methods. SCI was induced at Th10 in 12 animals, which were compared with 11 sham-operated controls. Spinal cord blood flow was measured in 7 adjacent regions of interest and in the sum of these 7 regions. Blood flow was quantified using CEU with intravenous microbubble injection. Spinal cord hemorrhage was measured on conventional B-mode sonogram slices. Results. CEU allowed us to measure the temporal and spatial changes in spinal cord blood flow in both groups. In the SCI group, spinal cord blood flow was significantly decreased in the global region of interest (P = 0.0016), at the impact site (epicenter), and in the 4 regions surrounding the epicenter, compared with the sham group. The blood flow decrease was maximum at the epicenter. No statistically significant differences between the sham groups were found for the most rostral and caudal regions of interest. Hemorrhage size increased significantly with time (P < 0.0001), from 30.3 mm(2) (+/- 2) after 5 minutes to 39.6 mm(2) (+/- 2.3) after 60 minutes. Conclusion. CEU seems reliable for quantifying temporal and spatial changes in spinal cord blood flow. After SCI, bleeding occurs in the spinal cord parenchyma and increases significantly throughout the first hour.