Magnetic resonance imaging based arterial spin labeling is a technique to measure renal blood flow. Renal perfusion measurement is an important tool to analyze renal function and to detect acute kidney injury. The perfusion measurement is based on two data acquisitions, one with a global inversion prepulse followed by one with a slice selective prepulse (FAIR). The prepulses lead to a labeling of blood water spins. In contrast to the global inversion prepulse, the slice selective inversion prepulse only labels the blood water spins inside the kidney but not the inflowing blood water spins. Subtraction of both images therefore reflects the local perfusion. A third image without the FAIR preparation pulse is measured to normalize the signal intensifiers on each patients.