In most cases, CT can show whether the cancer has metastasized or not, especially on enhanced CT. metastatic lesions often appear as rounded or round-like nodules on CT, with a regular shape, and sometimes there is not only one, but also a large number of metastatic lesions. However, if the metastatic lesion is smaller than 1cm, it is sometimes difficult to be detected on CT, and even if it is detected, it is difficult to distinguish the metastatic tumor from benign tumors. Even if they are detected, it is still difficult to distinguish them from benign tumors. There are other parts of the metastatic tumors, such as intracerebral metastatic tumors, which are difficult to be detected on CT or even enhanced CT. Cranial enhancement MRI can sometimes detect many metastatic tumors that are not seen on cranial CT.