If the blood vessels within the brain are to be imaged for examination, CTA is more effective than MRI for cerebral vascular imaging. CTA is performed by angiographic technique under CT scan through three-dimensional reconstruction, removing the skin, muscle, bone and other structures that do not need to be displayed, and showing only the patient’s vascular structures. CTA is also widely used in clinical practice to examine cerebral vascular CTA, coronary artery CTA, and carotid vascular CTA. CTA images are clear and accurate in diagnosis. CTA images are made by intravenous injection of iodine-containing contrast agent to the patient’s cerebral arterial rings, anterior cerebral arteries, middle cerebral arteries, posterior cerebral arteries, and their major branches, and can provide an important diagnostic basis for occlusive vascular lesions. MRI angiography does not require contrast, and it is not as clear as CTA for small vessels, but MRI can be more advantageous than CTA for brain parenchyma and observation of infarcted brain occupations in the brain.