van Damme W, Reolon M, Pereira N, Wackenheim C
Neuroradiology. 1977 Jun 27;13(4):209-14. doi: 10.1007/BF00344215.
A positive diagnosis of tumors located within the fourth ventricle should be based on specific signs therby excluding other space occupying lesions in the posterior fossa. These are a typical omega form of the hemispheric cerebellar branches on the lateral projection, and an also typical inverted 3 form of the PICA in the semiaxial projection. Alteration of the veins of the lateral recess of the fourth ventricle and of the precentral cerebellar vein are important venous signs. Indirect signs are found in the absence of tonsillar herniation with arterial and venous signs of AP stretching of the cerebellar tonsils.
第四脑室内肿瘤的阳性诊断应基于特定体征，从而排除后颅窝其他占位性病变。这些体征包括侧位片上半球小脑分支典型的欧米伽形，以及半轴位片上小脑后下动脉典型的倒3形。第四脑室侧隐窝静脉和小脑中央前静脉的改变是重要的静脉体征。间接体征表现为不存在扁桃体疝，但有小脑扁桃体动脉和静脉拉伸的体征。
