Brown M S, Kornfeld M, Mun-Bryce S, Sibbitt R R, Rosenberg G A
Center for Noninvasive Diagnosis, University of New Mexico School of Medicine, Albuquerque 87131.
J Neuroimaging. 1995 Jan;5(1):23-33. doi: 10.1111/jon19955123.
Complex changes in the appearance of blood on magnetic resonance images (MRIs) complicate interpretation of intracerebral hemorrhage. In this study serial MRIs of intracerebral hemorrhage were obtained at 1.5 T, using a recently developed model for brain hemorrhage, and the MRI findings were compared with histological findings. Hemorrhages were induced in 24 adult rats by the stereotactic injection of 0.5 unit of bacterial collagenase into the caudate/putamen. Initially, there was hypointensity seen on both T1- and T2-weighted images. Conversion to hyperintensity began on both T1- and T2-weighted images around 10 hours, when red blood cell lysis was observed histologically. By 24 hours, complete conversion to marked hyperintensity had occurred. Calculated T2 values increased twofold to fivefold after lysis, indicating that T2 effects dominate the conversion to hyperintensity seen after red blood cell lysis. At 24 hours there was a rim of intact red blood cells around the lesion, which was hypointense on MRI at a time when iron stains were negative. Fresh blood appears hypointense on T1- and T2-weighted images both at the early stages of a bleed and at later stages when rebleeding occurs. Collagenase-induced hemorrhage is a useful animal model to follow the evolution of paramagnetic effects of blood on MRI.
磁共振成像（MRI）中血液外观的复杂变化使脑内出血的解读变得复杂。在本研究中，使用最近开发的脑出血模型，在1.5T条件下获取脑内出血的系列MRI图像，并将MRI结果与组织学结果进行比较。通过向24只成年大鼠的尾状核/壳核立体定向注射0.5单位细菌胶原酶诱导出血。最初，在T1加权和T2加权图像上均可见低信号。在组织学观察到红细胞溶解时，T1加权和T2加权图像上大约在10小时开始转变为高信号。到24小时时，已完全转变为明显的高信号。红细胞溶解后计算得到的T2值增加了两倍到五倍，表明T2效应主导了红细胞溶解后所见的向高信号的转变。在24小时时，病变周围有一圈完整的红细胞，此时铁染色为阴性，而在MRI上该区域呈低信号。无论是在出血的早期还是在后期再出血时，新鲜血液在T1加权和T2加权图像上均呈低信号。胶原酶诱导的出血是一种有用的动物模型，可用于追踪血液顺磁效应在MRI上的演变过程。
