So an acute subdural hematoma causes symptoms within 2 days.

急性硬膜下血肿通常在2天内出现症状。

On a CT scan, an acute subdural hematoma shows up as a hyperdense mass, meaning that it looks more white than the surrounding healthy brain tissue.

在CT上，急性硬膜下血肿为高密度区域：也就是说那块区域比旁边的正常脑组织亮度更高。