In a pulse sequence diagram, what function does Gy serve?

In a pulse sequence diagram, Gy serves as the component responsible for phase encoding. This process involves the application of a gradient magnetic field along the y-axis (Gy), which helps to impart a phase shift to the spins in the imaging region. By varying the Gy field strength during the sequence, different areas of the image will experience unique phase shifts based on their spatial location.

Phase encoding is crucial for spatial localization of the signals in magnetic resonance imaging (MRI). It allows for the differentiation of tissues based on their spatial position, which is essential when reconstructing images from the collected data. Each pixel in the final image corresponds to a specific combination of frequency and phase encoding, enabling detailed and accurate visual representation of the anatomy being imaged.

The other options, while relevant to various functions in pulse sequences, do not represent the specific role of Gy. Slice selection, for instance, typically involves the application of a gradient along the z-axis (Gz) to isolate a particular slice of tissue. Frequency modulation relates to the manipulation of the frequency of the radiofrequency (RF) pulses, and timing synchronization pertains to managing the timing between different components of the sequence. However, the unique role of Gy in imparting phase information establishes its clear function in phase encoding