Cerebral contusion injury on CT shows localized cerebral edema with low density, which ranges from several centimeters to the whole cerebral hemisphere or cerebellar hemisphere, and the medulla and the cortex can be involved, and it is round, oval, or irregular, with clear boundary. Small hemorrhagic foci appear as scattered punctate high-density shadows in low-density areas. Due to edema and small hemorrhagic foci, the ventricles on the diseased side may be shifted to the contralateral side by compression, and the ventricles on the diseased side may become smaller or even completely occluded if the lesion is larger in scope. If the edema and hemorrhage foci of mild cerebral contusion injury are gradually absorbed, the above CT manifestations may also gradually disappear, and when cysts are formed by necrosis and liquefaction, the low-density area will persist for a long time, and the CT value will be close to that of cerebrospinal fluid, and the edge of the area will be smooth and neat, and the multiple cerebral contusion injuries as well as concomitant intracerebral and extracerebral hematomas will be clearly displayed on CT images, and CT is more superior than MRI to the display of subacute and chronic cerebral contusion injuries.