A method of magnetic resonance imaging of cerebral blood flow uses a pulse sequence of a rapid gradient-echo method, wherein the pulse is an RF pulse having a slice gradient, a read gradient and a phase-encode gradient. The RF pulse is provided with a flip angle of between 45 and 60 degrees, and an additional gradient is added to each of the slice gradient, read gradient and phase-encode gradient, thereby diffusing and refusing proton spin in the cerebral blood flow. Very slight changes in the blood flow in the brain can be imaged and diabetes can be diagnosed by detecting the increase in the blood flow in a specific brain region after systemic administration of insulin.