Perfusion imaging is a medical imaging technique used to evaluate blood flow to tissues and organs in the body. This type of imaging is commonly used in the fields of radiology, cardiology, and neurology to assess the function of organs and tissues by measuring the distribution of blood flow. Perfusion imaging can be conducted using a variety of imaging modalities, including magnetic resonance imaging (MRI), computed tomography (CT), and nuclear medicine techniques such as single photon emission computed tomography (SPECT) and positron emission tomography (PET). This imaging technique is useful in diagnosing a variety of conditions, such as stroke, heart disease, and certain types of cancer, as it provides valuable information about tissue viability and function. In addition, perfusion imaging can help guide treatment decisions and monitor the effectiveness of therapies in patients with various medical conditions.