What term describes the process where only half of the views of k-space are filled in the frequency axis?

The term that describes the process where only half of the views of k-space are filled in the frequency axis is partial or fractional echo. This technique is employed in MRI to reduce scan time or to improve temporal resolution by capturing only a portion of the k-space data, particularly in sequences like Fast Spin Echo.

In a typical MRI acquisition, k-space is filled fully for each image, but using this method allows clinicians to reconstruct images while only acquiring a fraction of the total data required. This can lead to improved patient throughput and reduced motion artifacts, as it shortens the time the patient must remain still during the scan.

Other terms mentioned are related but do not specifically capture the essence of filling only half of the k-space. For example, parallel imaging involves using multiple coils to accelerate data acquisition but fills k-space in a different manner, aiming primarily at reducing scan time through spatial encoding. Anti-aliasing is a technique used to minimize image artifacts related to undersampling but does not describe the process of filling k-space. Half Fourier refers to a technique more specifically related to using half of the k-space data for image reconstruction, which can introduce specific considerations about image quality. Partial echo generally relates to acquiring only a part of the signal in each TR but