Which approach is most effective at improving the signal-to-noise ratio in MRI?

The most effective approach to improving the signal-to-noise ratio (SNR) in MRI is to increase slice thickness and decrease frequency encoding steps. Increasing slice thickness enhances the SNR because a thicker slice encompasses a larger volume of tissue, which means more protons are available to contribute to the signal. This larger number of protons results in a stronger overall signal, thereby improving the SNR.

Decreasing frequency encoding steps also positively impacts SNR. By reducing the number of steps in the frequency encoding, you allow for more signal to be captured in each step, further enhancing the overall quality of the image. This combination of increasing slice thickness and improving signal capture through fewer encoding steps leads to a more pronounced signal against the background noise.

While other approaches might influence image quality or other factors, they do not directly enhance the SNR as effectively as the significant changes made by increasing slice thickness and optimizing frequency encoding.