Magnetic Resonance Imaging (MRI) Practice Test

What is it called when only half of the views of k-space are filled in the frequency axis?

1. Full echo

2. Partial or fractional echo

3. Complete k-space acquisition

4. Expanded k-space utilization

The correct answer is: Partial or fractional echo

When only half of the views of k-space are filled in the frequency axis, the term used is "partial or fractional echo." In MRI, k-space represents the frequency and phase information of an image. It can be understood as an array that contains the raw data collected from the MRI scan, which is then transformed into the final image through mathematical processing. By only filling half of the k-space, a partial or fractional echo acquisition technique allows for faster imaging by reducing the total time required for data collection. This approach can also result in lower image quality compared to full k-space acquisition, leading to potential trade-offs between scan time and the fidelity of the image produced. Utilizing a partial echo means that certain image characteristics may change, influencing factors like signal-to-noise ratio and spatial resolution. Thus, while this method can be beneficial in terms of efficiency, MRI technologists need to balance these factors based on the diagnostic requirements of the scan.