PWI stands for Magnetic Resonance Perfusion Imaging. The clinical application of this method is still limited and it is currently used only as a semi-quantitative means of clinical and basic research on hemodynamics. This technique involves the rapid injection of contrast into the peripheral veins and the detection of the target organ using a fast MR imaging sequence with high temporal resolution to obtain hemodynamic information reflecting the tissue. Nowadays, this technique is also applied only to the study of cerebral ischemic lesions, the blood supply to brain tumors, the study of myocardial ischemia, and renal and hepatic perfusion.