The targeted audience of this talk are physicians, interested in gaining insights into the different techniques of MR angiography. Advantages of the different approaches will be highlighted in order to enable the audience to select the appropriate approach depending on vessel territory and clinical question.Summary: Contrast enhanced and non-contrast enhanced MR angiography represent the two main methods for delineation of vessels. In contrast enhanced MRA, classically spatial resolution and temporal resolution have to be balanced against each other. View sharing and central read out of k-space have been introduced for subsecond acquisition of high resolution dynamics. This technique has a broad spectrum of clinical applications. In non-contrast MRA the classical approaches time-of-flight and phase contrast angiography suffered from long acquisition time and were prone to flow artifacts in regions with non-laminar flow. Application of balanced steady state free precession with flow sensitive dephasing allows for selective delineation of arteries with high signal intensity and high spatial resolution without flow related artefacts. This technique has already been demonstrated to be of high clinical impact in many vessel territories including the upper and lower extremities.MRA can generally be subdivided into techniques with and without application of contrast media. Contrast enhanced MRA is usually carried out with T1-weighted spoiled gradient echo sequences and central k-space reads out. Methods such as TWIST (time resolved angiography with interleaved stochastic readout) or TRICKS (time resolved imaging of contrast kinetics) allow for subsecond resolution, while spatial resolution is preserved. In general a trade of between time resolution and spatial resolution has to be balanced according to the clinical question. While information regarding contrast is contained in the central part of k-space, information regarding sharpness of vessel borders and small branches is present in the peripheral parts of k-space. View-sharing is a technique , which makes use of the non linearity of information contained in k-space. Usually, first a non-contrast enhanced high resolution frame is obtained. While the contrast bolus travels through the vessel territory the central parts of k-space are read out and imaging reconstruction is performed with data from the non contrast frame and the later obtained frames. Periodically the peripheral parts of k-space are read out and used for image reconstruction. This approach is termed view-sharing and affords for high temporal and spatial resolution. A combination of the standard approach and TWIST has been clinically established for assessment of run of vessels of the lower leg. Nevertheless such techniques display only the vessel lumen, similar to conventional angiography. They should be applied for indications, which otherwise would apply for conventional imaging, such as assessing for vessel occlusion or stenosis, or delineation of the feeding and run of vessels in malformations. If the vessel wall must be delineated, other approaches should be preferred.Time-of-flight and phase contrast angiography are the two classical non-contrast techniques for MRA. Both methods suffered from length of acquisition and artefacts, associated with non laminar flow. More recently alternatives, such as fast spin echo sequences using the high signal intensity of inflowing spins have been adapted for larger vessel territories such as the lower legs. Arterial spin labeling is a technique, that allows for selectively delineation of flow, provided by a given artery. In principle, a pulse is applied for labeling of inflowing blood. Which provides high signal intensity in the imaged region. Selective labeling of carotid arteries provides information regarding potential vessel dominance for intracranial perfusion. The balanced steady state free precession (SSFP) sequence is the sequence with the highest signal intensity due to the use of signal obtained from stimulated echo, spin echo and free-precession decay. This inherent high signal intensity renders this sequence highly suited for non-contrast MRA. By using flow sensitive dephasing, this sequence can be applied for selectively delineation of arterial flow. Acquisition is ECG triggered and one frame is acquired in systole while the other is obtained in diastole. Subtraction of both frames affords for excellent background subtraction and almost zero signal from venous vessels, while the arteries remain bright.