You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is Below what values of cerebral blood flow, Ischemia occurs in the brain? and explain in detail?
Cerebral blood flow <20 mL/100 g tissue per minute cause Ischemia without infarction unless prolonged for several hours or days. Transient ischemic attack - Patient may experience only transient symptoms, if blood flow is restored to ischemic tissue before significant infarction develops. Normal cerebral blood flow (CBF) - 50-55 mL/100 g/min.