Magnetic Resonance Imaging (MRI) Practice Test

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Prepare for your MRI Test with flashcards and diverse question types. Each question includes hints and explanations for better understanding. Boost your confidence and ace your exam!

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Which option would yield a lower signal-to-noise ratio?

Increase in TR
Larger FOV
Higher NEX
Increase in TE

The correct answer is: Increase in TE

Increasing the echo time (TE) is known to yield a lower signal-to-noise ratio (SNR). This is because a longer TE corresponds to a longer time between the excitation of the tissue and the measurement of the signal. As time increases, there is more opportunity for the signal to be dispersed and scattered, leading to a reduction in the overall signal that can be detected. Furthermore, noise remains relatively constant during this time, so as the signal diminishes while noise remains, the SNR consequently declines. In contrast, other options tend to enhance the SNR. For instance, increasing the repetition time (TR) generally allows more time for the tissues to relax, thus increasing the available signal. A larger field of view (FOV) can gather more signal from a greater volume of tissue, while a higher number of excitations (NEX) increases the SNR by averaging multiple acquisitions, thereby improving the quality of the signal relative to the noise.