Stroke is devastating and a common cause of death. Early recognition and treatment of stroke reduces the risk of death and disability. The initial screening CT initiates the pathway of care for the patient hence it is important for frontline doctors to appreciate the subtle changes that occur in a brain CT scan in stroke. Prompt recognition of stroke is covered extensively in this chapter because of the eminently treatable nature of this disease. In addition, the subtle changes in density in ischemic stroke are clearly discussed while emphasizing and illustrating the time dependent nature of this observation. Although outside the scope of this book, the uses of CT angiogram to further investigate these patients (advanced imaging) is mentioned for the curious reader.