Noninvasive physiologic vascular studies play an important role in the diagnosis and characterization in peripheral arterial disease (PAD) of the lower extremity. These studies evaluate the physiologic parameters of blood flow through segmental arterial pressures, Doppler waveforms, and pulse volume recordings. Collectively, they comprise a powerful toolset for defining the functionality of the arterial system, localizing the site of disease, and providing prognostic data. This technology has been widely adopted by diverse medical specialty practitioners, including radiologists, surgeons, cardiologists, and primary care providers. The use of these studies increased substantially between 2000 and 2010. Although they do not employ imaging, they remain a critical component for a comprehensive radiologic vascular laboratory. A strong presence of radiology in the diagnosis of PAD adds value in that radiologists have shifted to noninvasive alternatives to diagnostic catheter angiography (DCA), such as computed tomography (CT) and magnetic resonance (MR) angiography, which provide a more efficient, less-expensive, and lower-risk alternative. Other specialties have increased the use of DCA during the same period. The authors provide a review of the relevant anatomy and physiology of PAD as well as the associated clinical implications. In addition, guidelines for interpreting the ankle-brachial index, segmental pressures, Doppler waveforms, and pulse volume recordings are reviewed as well as potential limitations of these studies. Noninvasive physiologic vascular studies are provided here for review with associated correlating angiographic, CT, and/or MR findings covering the segmental distribution of PAD as well as select nonatherosclerotic diagnoses. ©RSNA, 2016.