McAllister J P, Cohen M I, O'Mara K A, Johnson M H
Department of Anatomy, Temple University School of Medicine, Philadelphia, Pennsylvania.
Neurosurgery. 1991 Sep;29(3):329-40.
Although previous ultrasonographic studies did monitor ventricular enlargement successfully in experimentally-induced models of feline hydrocephalus, the resolution of neuroanatomic detail was relatively poor after placement of a ventriculoperitoneal (VP) shunt because the skull had ossified over the coronal sutures. Therefore, the present study employed magnetic resonance imaging to follow the progression of ventriculomegaly more accurately, as well as to evaluate the compensatory effects of VP shunting. Hydrocephalus was induced in kittens between 7 and 10 days old by injection of kaolin into the cisterna magna. Age-matched controls received similar injections of saline. At 9 to 14 days after the kaolin injection, the hydrocephalic animals received VP shunts. Anesthetized kittens were scanned at various intervals before and after shunt placement and were killed for morphological correlation. The features observed on the magnetic resonance imaging scans were consistent with the gross morphological changes that accompanied ventricular enlargement. The lateral ventricle began to enlarge as early as 1 day after the kaolin injection, and within 3 days, both the occipital and temporal horns, along with the 4th ventricle, showed signs of moderate dilatation. By 5 days, a bilateral communication had been established through the septum pellucidum. Continued expansion of the ventricular system occurred from 6 to 20 days after injection, to the point where the cerebral cortex was reduced to less than 25% of its original thickness. The internal capsule was stretched and edematous, the caudate nucleus was compressed ventrolaterally, and the cerebellar hemispheres were eroded and/or compressed. Animals in which shunts were successfully placed demonstrated a dramatic improvement in behavior, and a reduction of about 50% in the size of the lateral ventricles within 2 days. In some cases, the lateral ventricles became slit-like within 1 week. When they were killed, about half of the animals that received shunts exhibited mild to moderate ventriculomegaly. These results indicate that magnetic resonance imaging is an excellent method for visualizing the morphological changes associated with this animal model, that these alterations occur soon after the onset of hydrocephalus, and that VP shunting can successfully reduce ventriculomegaly.
尽管先前的超声研究确实在实验诱导的猫脑积水模型中成功监测到了脑室扩大，但在放置脑室腹腔（VP）分流管后，由于颅骨在冠状缝处已经骨化，神经解剖细节的分辨率相对较差。因此，本研究采用磁共振成像更准确地跟踪脑室扩大的进展情况，并评估VP分流的代偿作用。通过向7至10日龄的小猫小脑延髓池注射高岭土诱导脑积水。年龄匹配的对照组接受类似的盐水注射。在高岭土注射后9至14天，脑积水动物接受VP分流管植入。在分流管放置前后的不同时间间隔对麻醉的小猫进行扫描，并将其处死以进行形态学对照。磁共振成像扫描观察到的特征与伴随脑室扩大的大体形态变化一致。早在高岭土注射后1天侧脑室就开始扩大，3天内枕角和颞角以及第四脑室都出现了中度扩张的迹象。到5天时，通过透明隔建立了双侧连通。注射后6至20天脑室系统持续扩张，直至大脑皮层厚度减至不到其原始厚度的25%。内囊被拉伸并水肿，尾状核被向腹外侧压缩，小脑半球被侵蚀和/或压缩。成功放置分流管的动物行为有显著改善，侧脑室大小在2天内缩小约50%。在某些情况下，侧脑室在1周内变成裂隙状。处死时，约一半接受分流管植入的动物表现出轻度至中度脑室扩大。这些结果表明，磁共振成像是观察与该动物模型相关形态学变化的极佳方法，这些改变在脑积水发作后很快就会出现，并且VP分流可以成功减轻脑室扩大。
