Mihai Georgeta, Nout Yvette S, Tovar C Amy, Miller Brandon A, Schmalbrock Petra, Bresnahan Jacqueline C, Beattie Michael S
Department of Radiology, The Ohio State University, Columbus, Ohio, USA.
J Neurotrauma. 2008 Jan;25(1):1-18. doi: 10.1089/neu.2007.0338.
Magnetic resonance imaging (MRI) should be a powerful tool for characterization of spinal cord pathology in animal models. We evaluated the utility of medium-field MRI for the longitudinal assessment of progression of spinal cord injury (SCI) in a rat model. Thirteen adult rats were subjected to a 6.25 or 25 g-cm unilateral cervical SCI, and underwent MRI and behavioral tests during a 3-week study period. MRI was also performed post-mortem. Quantification of cord swelling, hypointense and hyperintense signal, and lesion length were the most valuable parameters to determine and were highly correlated to behavioral and histopathological measures. Immediately after injury, MRI showed loss of gray matter-white matter differentiation, presence of scattered hyperintense signal and local hypointense signal, and cord swelling in both groups. At 7 days after injury, the spinal cord in the 25 g-cm group was significantly larger than that of the 6.25 g-cm group (p = 0.02). Contrast enhancement of the lesion was seen at 24 h in the 6.25 g-cm group, and at 24 h and 7 days in the 25 g-cm group. The volume of hypointense signal, representing hemorrhage, throughout the lesion region was significantly larger in the 25 g-cm compared to the 6.25 g-cm group at both 14 and 21 days after SCI (p, </= 0.04). The appearance of the scattered hyperintense signal, initially representing edema, at later time points changed to a rim of hyperintense signal surrounding the lesion cavity. Significant correlations were found between cord swelling at 7 days after SCI, and lesion length and gray and white matter sparing as determined by histopathology. Other parameters that were highly correlated with histopathology were quantity of hyperintense and hypointense signal, and in vivo lesion length. Hypointense signal and in vivo lesion length were highly correlated to behavior. Significant correlation was also found between parameters determined by MRI: swelling, hypointense signal, hyperintense signal, and lesion length. MRI is a valuable imaging modality to assess the temporal evolution of SCI and to distinguish different severities of cervical SCI in rats. In future, MRI could be applied as a screening tool to either administer goal-directed therapies, or enable even group distribution, prior to therapeutic intervention for example through quantification and matching of swelling and edema.
磁共振成像（MRI）应该是用于表征动物模型中脊髓病理学的有力工具。我们评估了中场MRI在大鼠模型中对脊髓损伤（SCI）进展进行纵向评估的效用。13只成年大鼠接受了6.25或25 g-cm的单侧颈髓SCI，并在为期3周的研究期间接受了MRI和行为测试。还在死后进行了MRI检查。脊髓肿胀、低信号和高信号以及病变长度的量化是最有价值的参数，并且与行为和组织病理学测量高度相关。损伤后立即，MRI显示两组均出现灰质-白质分化丧失、散在高信号和局部低信号以及脊髓肿胀。损伤后7天，25 g-cm组的脊髓明显大于6.25 g-cm组（p = 0.02）。6.25 g-cm组在24小时时可见病变的对比增强，25 g-cm组在24小时和7天时可见。在SCI后14天和21天，25 g-cm组整个病变区域代表出血 的低信号体积明显大于6.25 g-cm组（p≤0.04）。散在高信号最初代表水肿，在后期时间点变为围绕病变腔的高信号边缘。在SCI后7天的脊髓肿胀与组织病理学确定的病变长度以及灰质和白质保留之间发现了显著相关性。与组织病理学高度相关的其他参数是高信号和低信号的数量以及体内病变长度。低信号和体内病变长度与行为高度相关。在MRI确定的参数之间也发现了显著相关性：肿胀、低信号、高信号和病变长度。MRI是评估SCI的时间演变以及区分大鼠颈髓SCI不同严重程度的有价值的成像方式。未来，MRI可作为一种筛查工具，例如在治疗干预之前通过量化和匹配肿胀和水肿来实施目标导向治疗或实现均匀分组。
