How do GRE images differ from SE images regarding blood flow?

GRE (Gradient Echo) images demonstrate flow-related enhancement due to their unique imaging sequence, which utilizes variations in magnetic field gradients to create contrast. This enhancement occurs because blood flow results in different precession frequencies in moving spins compared to stationary spins, which can lead to increased signal intensity in areas with high flow. As a result, GRE images can highlight dynamic processes like blood circulation more effectively than SE (Spin Echo) images.

In contrast, SE imaging relies on the properties of the spins returning to equilibrium after excitation and tends to provide better anatomical detail and tissue characterization, but does not specifically highlight flow as effectively. Therefore, while both imaging techniques have their respective advantages, the distinct flow-related enhancement observed in GRE images makes them particularly useful in vascular studies and other applications where blood flow dynamics are relevant.