ABSTRACT
Objective To evaluate the clinical value of susceptibility?weighted imaging(SWI) in detecting intramedullary hemorrhage of traumatic acute spinal cord injury. Methods From October 2012 to December 2014, 37 TSCI (traumatic spinal cord injuries) patients undergone the MRI scans including routine MRI and SWI were enrolled. Further according to ASIA classification standard, all patients were evaluated as ASIA A (n=4), ASIA B (n=4), ASIA C (n=19) and ASIA D (n=10). Referring to axial T2WI images at the same slice, the manifestations of hemorrhage in amplitude image, phase image and SWI were evaluated. At the slice with maximal size of hemorrhage area and its neighboring slices, the hemorrhage regions were manually drawn; and the total area was automatically calculated. The number of hemorrhage lesions was defined as the number of hemorrhage lesions at single slice × slice number. One?way ANOVA was used to compare the differences among different grading ASIA in terms of hemorrhage area and number. Meanwhile, the relations between hemorrhage area and ASIA grade; hemorrhage number and ASIA grade were evaluated by Spearman rank correlation. Results The hemorrhage was detected by SWI in 15 patients, including 4 ASIA A, 4 ASIA B, 7 ASIA C. Hemorrhage represents as isointense in T1WI and a slightly low signal intensity or isointense in the center companied by high intensity at circus in T2WI. In magnitude image and SWI hemorrhage appears as low signal intensity and low signal intensity in the center companied by high intensity at circus in phase image. In detecting the hemorrhage, SWI (98 lesions were detected) was 5.4 times of T2WI (19 lesion were detected). As for the number of hemorrhage, significant differences were found among ASIA grading A, B and C (grading A:22.5 ± 1.3, grading B:19.5 ± 1.3, grading C:4.0 ± 1.1;F=38.720, P<0.01); Further the pairwise comparison showed statistical significance (P<0.05); besides, the number of hemorrhage lesions closely related with the ASIA grade (r=0.864, P<0.01). For the hemorrhage area, the calculated results of grading ASIA A, B and C were (23.5 ± 0.6), (21.8 ± 1.9), (3.9 ± 0.7) mm2, respectively; there were significant differences among the different ASIA grades (F=29.987, P<0.001);furthermore the hemorrhage area also showed closely relation with the ASIA grade (r=0.778, P<0.01). Conclusions SWI is more sensitive in detecting the hemorrhage in traumatic acute spinal cord injury. The more number and area of bleeding area suggest the more severe of the damage level.