MR angiography using fast imaging techniques

The use of fast imaging techniques provides new information about blood flow, by calculation of dynamic parameters. Using ECG-triggered gradient echo sequences, a section is imaged at various trigger delay times. Different flow velocities at several delay times lead to images with varying intensities within the vessels. According to the actual hear rate, 25-32 delay times may be sampled during one measurement. By processing the whole window of a temporal series, new flow-sensitive images are generated (e.g., by calculating the standard deviation pixel by pixel). Varying components of the arteries are extracted, while stationary tissue is eliminated. The high temporal resolution obtained with fast imaging techniques allows the display of flow phenomena in vessels in the form of MR imaging movies