Which technique is most effective for reducing chemical shift artifacts?

• A. Decrease rBW
• B. Increase bandwidth
• C. Increase rBW
• D. Reduce slicethickness

Answer: (C)

The most effective technique for reducing chemical shift artifacts is to increase the receive bandwidth (rBW). Chemical shift artifacts arise due to differences in resonant frequencies of fat and water protons, which can lead to misregistration of fat and water signals in images, particularly at interfaces.

Increasing the receive bandwidth allows for a wider range of frequencies to be captured during imaging, which helps to minimize the differences in frequency between fat and water. By decreasing the bandwidth, you are essentially allowing more significant differences in resonance to affect the resulting image, hence potentially worsening the artifact.

When the receive bandwidth is increased, it shortens the time available for signal acquisition, which leads to a reduction in the chemical shift artifact. This is because the higher bandwidth captures a wider range of frequencies more accurately, ensuring better alignment of fat and water signals, thus improving image clarity and reducing misalignment errors associated with chemical shifts.

While reducing slice thickness might improve spatial resolution, it does not directly address the frequency differences contributing to chemical shift. Similarly, modifying rBW or reducing bandwidth can lead to an increase in these artifacts rather than a reduction. Therefore, increasing bandwidth is the most effective method in this context.