Zhang Gui-Xiang, Li Kang-An, Zhao Jing-Long, Zhang Feng, Hu Yun-Sheng, Li Yu-Jie
Department of Radiology, Shanghai Jiaotong University, Affilliated First Hospital, Shanghai 200080, China.
Zhonghua Yi Xue Za Zhi. 2008 Dec 23;88(47):3369-73.
To establish a rabbit model of cerebral spinal flow metastasis, to analyze the growth rate of tumor, and to investigate the value of MRI in monitoring the biology of tumor compared with pathology.
Twenty-four New Zealand white rabbits were inoculated with suspension of VX(2) tumor cells in the subarachnoid space via the foramen magnum (experimental group), and 6 rabbits were inoculated with normal saline (control group). MRI examination, including non-enhanced T(1)WI, T(2)WI, and FLAIR sequences and then T(1)WI, FLAIR after dynamic contrast enhanced with Gd-DTPA were done 7 approximately 22 days after inoculation with a 3-day interval. The rabbits were killed after the last MRI scan with their spinal cords, spinal meninges, and tumor taken out to undergo microscopy.
(1) MRI plain scan showed that in the experimental group 2 nodi in the medulla and 1 nodes in the cervical spinal cord were found with low signal on T(1)WI and high signal on T(2)WI; and FLAIR imaging showed local lesions with medial signal in 6 rabbits (25%). And no abnormal signs were seen in the control group. (2) MRI enhancement showed that in the experimental group the images of 15 rabbit models were enhanced markedly with irregular thickening of meninges or nodules at the subarachnoid space on T(1)WI, positive signs were confirmed on FLAIR sequence in 16 of the 24 rabbits, and positive signs were noted on DCE-MRI scanning in 18 of the 24 rabbits (75%). In the control group 5 of the 6 rabbits were negative in images. Microscopy showed thickened of meninges and spinal meninges in 20 of the 24 rabbits of the experimental group and spinal cord metastasis in 22 rabbits. No pathological changes were seen in the control group. Statistics showed a CSF metastasis rate of 91.67%. There were significant difference between the plain scan and T(1)WI with enhancement (P < 0.01) and between FLAIR scan and FLAIR enhancement scans. There was a significant difference between T(1)WI and FLAIR enhancement and pathological findings (P < 0.05). There was no significant difference between DCE-MRI method and pathological results (P > 0.05).
Gd-DTPA enhanced MRI scan sequences has a high sensitivity and specificity and can be used in monitoring the growth of CSF metastasis. There is a disparity between the MRI signs and pathological findings. It is a key that to improve the spatial resolution of machine and to investigate the best method for detecting early metastasis.
建立兔脑脊髓液转移瘤模型，分析肿瘤生长速率，并探讨磁共振成像（MRI）与病理学相比在监测肿瘤生物学特性方面的价值。
24只新西兰白兔经枕骨大孔在蛛网膜下腔接种VX(2)肿瘤细胞悬液（实验组），6只接种生理盐水（对照组）。接种后7至22天，每隔3天进行MRI检查，包括平扫T(1)WI、T(2)WI及FLAIR序列，然后用钆喷酸葡胺（Gd-DTPA）进行动态增强扫描后的T(1)WI、FLAIR成像。最后一次MRI扫描后处死兔子，取出脊髓、脊膜及肿瘤进行显微镜检查。
（1）MRI平扫显示，实验组延髓发现2个结节，颈髓发现1个结节，T(1)WI呈低信号，T(2)WI呈高信号；FLAIR成像显示6只兔子（25%）局部病灶呈中等信号。对照组未见异常征象。（2）MRI增强扫描显示，实验组15只兔模型图像明显强化，T(1)WI可见脑膜不规则增厚或蛛网膜下腔结节，24只兔子中16只在FLAIR序列上有阳性表现，24只兔子中18只（75%）在DCE-MRI扫描中有阳性表现。对照组6只兔子中有5只图像为阴性。显微镜检查显示，实验组24只兔子中有20只脑膜和脊膜增厚，22只发生脊髓转移。对照组未见病理改变。统计学显示脑脊液转移率为91.67%。平扫与增强T(1)WI之间（P < 0.01）以及FLAIR扫描与FLAIR增强扫描之间差异有统计学意义。T(1)WI和FLAIR增强与病理结果之间差异有统计学意义（P < 0.05）。DCE-MRI方法与病理结果之间差异无统计学意义（P > 0.05）。
Gd-DTPA增强MRI扫描序列具有较高的敏感性和特异性，可用于监测脑脊液转移瘤的生长。MRI征象与病理结果存在差异。提高机器空间分辨率并探索检测早期转移的最佳方法是关键。
