What is the result of increasing the transmit bandwidth in MRI?

Increasing the transmit bandwidth in MRI leads to a decreased signal-to-noise ratio (SNR). This phenomenon occurs because a wider bandwidth allows a broader range of frequencies to be transmitted during the imaging process. While this can provide benefits such as reducing chemical shift artifacts and improving time efficiency, it also results in a lower SNR.

The SNR is affected due to the inclusion of noise along with the desired signal over the expanded bandwidth. As you incorporate a wider range of frequencies, the contribution of noise becomes more pronounced relative to the actual signal being received. This ultimately diminishes the clarity and quality of the images produced.

Other aspects of image quality, such as spatial resolution and image contrast, are generally more positively influenced by adjustments to other parameters (like voxel size or contrast agents), rather than bandwidth alone. Increased slice thickness can occur if other parameters are not optimized, but the direct effect of increased bandwidth is primarily seen in the SNR, as noted.