Which of the following best describes a FSE sequence?

A fast spin echo (FSE) sequence is characterized by the generation of multiple spin echoes in quick succession. This method is advantageous in clinical MRI because it significantly reduces acquisition time while maintaining high-quality images. In an FSE sequence, after an initial 90° pulse, a series of 180° refocusing pulses are applied, creating a train of spin echoes. The echoes are acquired as they are produced, allowing for multiple slices to be generated rapidly.

This method improves efficiency in imaging, particularly for sequences that require high-resolution images without extensive time in the scanner. The train of spin echoes also enhances the signal-to-noise ratio and allows for greater flexibility in adjusting imaging parameters to achieve optimal results. Thus, the description of a fast spin echo sequence as generating a train of spin echoes captures the essence of how this technique operates and its advantages in MRI applications.