Which of the following does NOT yield a higher signal-to-noise ratio?

The correct answer is based on an understanding of how different imaging parameters affect the signal-to-noise ratio (SNR) in MRI. Increasing the echo time (TE) typically leads to a lower SNR. This is primarily because a longer TE allows more time for T2 decay to occur, which decreases the overall signal detected by the MRI system. T2 decay refers to the loss of signal intensity due to the spin-spin interactions of the protons in the tissue, which means that the longer you wait to measure the signal after excitation, the less signal remains.

On the other hand, increasing the repetition time (TR), enlarging the field of view (FOV), and increasing the number of excitations (NEX) all contribute positively to SNR. Increasing TR allows more time for recovery of the longitudinal magnetization before the next excitation, resulting in a stronger signal. A larger FOV encompasses a broader range of tissue, increasing the amount of signal collected. Higher NEX essentially means that multiple signals are acquired and averaged, which enhances the SNR by reducing random noise.

Thus, understanding these principles of MRI imaging helps clarify why an increase in TE actually detracts from the SNR, making it the correct answer for the question.