目的：本文目的是对后颅窝囊肿的ＣＴ－ＭＲ影像学的诊断作用进行评价。材料与方法：１２例后颅窝囊肿的ＣＴ和ＭＲ影像表现进行了分析，探讨了其与临床表现和类型的相关性。结果：本组病例包含Ｄａｎｄｙ－Ｗａｌｋｅｒ囊肿（５例）、蛛网膜囊肿（３例）和巨枕大池（４例），ＣＴ和ＭＲ都可提供无创性检测手段。结论：ＣＴ和ＭＲ二者对后颅窝囊肿的诊断均有效，但在显示病变的性状、大小和轮廓方面，ＭＲ比ＣＴ稍胜一筹 Objective: The purpose of this article is to evaluate the diagnostic role of CT-MR imaging in posterior fossa cysts. Materials and Methods: CT and MR images of 12 cases of posterior fossa cysts were analyzed and their correlation with clinical manifestations and types was explored. Results: This group of patients included Dandy-Walker cysts (5 cases), arachnoid cysts (3 cases), and giant occipital plexus (4 cases). Both CT and MR could provide non-invasive detection methods. Conclusion: Both CT and MR are effective in the diagnosis of posterior fossa cyst, but MR is better than CT in showing the character, size and contour of the lesion.