How does increasing TR affect the signal-to-noise ratio (SNR)?

Increasing the repetition time (TR) in magnetic resonance imaging (MRI) can enhance the signal-to-noise ratio (SNR). TR is the duration of time between successive excitation pulses, and a longer TR allows for more time for longitudinal relaxation, leading to a stronger signal when the next acquisition occurs. This increased signal improves the overall quality of the image, resulting in a higher SNR.

Additionally, a longer TR can also lead to a reduction in the effects of noise since it allows greater time for the system to stabilize between acquisitions. Moreover, when TR is increased, the system can average out noise over multiple signals, further improving SNR. Hence, the relationship between TR and SNR is directly proportional: as TR increases, SNR tends to increase as well, making the chosen answer accurate in this context.