Cerebral Ischemia occurs when cerebral blood flow is less than:

Answer is B (20 m1/100g / minute): Cerebral blood flow < 20 ml / 100g tissue per minute causes cerebral ischemia without infarction (Harrison 's 18 th /3271) Critical Cerebral Blood Flow Effects * 5 20 mU100 gm/minute * Cerebral Ischemia without infarction (Reversible unless prolongedfOr several hours or days) * Clinical syndrome of TIA * Consciousness is usually lost as the brain tissue loses the capacity to make neurotransmitter substances and coma ensues * Damage is Reversible * 16-18 ml / 100 gm / minute * Cerebral Infarction within one hour * 10 ml / 100 gm / minute * Cerebral Infarction within several minutes * Membrane integrity is lost * Biochemical cascade of neuronal destruction becomes irreversible * Zero ml / 100 gm / minute * Death of Brain tissue within 4 - 6 minutes