颅内诸多疾病经增强扫描呈环形病灶。环形病灶是指病变周边出现环状高密度影，环内密度较低，且低密度最大径不小于环壁的平均厚度。目前较常见的疾病有胶质瘤、转移瘤、结核、脑脓肿、脑囊虫等。以上疾病可致脑部CT中所表现的环形病灶形态多种多样，表现不一，环壁厚薄不等， Many intracranial diseases were enhanced scan ring lesions. Annular lesions refers to the appearance of ring-shaped high-density lesions around the ring, the lower the density, and the maximum density of less than the average thickness of the ring wall. Currently more common diseases are glioma, metastases, tuberculosis, brain abscess, cerebral cysticercosis and so on. The above diseases can cause brain lesions in the performance of CT showed a variety of annular lesions, varying performance, ranging from ring thickness,