Cerebral blood supply deficiency is a disease caused by insufficient blood flow to the brain from various causes, resulting in brain dysfunction, mostly seen in lesions of the cerebral vessels themselves. There are four visual examination methods that can detect the status of blood vessels: 1. Ultrasonography. This includes cervical vascular ultrasound and TCD examination, which can detect the diameter of cerebral blood vessels, the velocity of blood flow, the presence of plaques in the vessels, as well as the stability and instability of plaques through echo. 2, CTA examination. By playing contrast agent, the whole cerebral blood vessels are visualized by CT machine to detect the state of cerebral blood vessels.3.MRA, also called nuclear magnetic angiography. DSA, also called whole brain angiography, is a minimally invasive test that can detect not only the presence of plaque and stenosis, but also the compensatory blood supply to brain tissue from other vessels. In addition, patients with inadequate blood supply to the brain also need to undergo electrocardiogram and cardiac ultrasound to rule out cardiogenic diseases causing inadequate blood supply to the brain and to see if the heart has arrhythmias, coronary artery disease, cardiomyopathy, heart failure and other cardiac disorders. These tests are the tests to be done for insufficient blood supply to the brain, which can clearly detect the lesions and find out the causes of insufficient blood supply to the brain.