Final answer:
To improve the SNR in an MRI with a short scan time, increasing the number of excitations (NEX) will lead to a clearer image as it allows for more signal averages.
Step-by-step explanation:
For an MRI with a low Signal-to-Noise Ratio (SNR) and a short scan time of approximately 2 minutes, an increase in number of excitations (NEX) will help increase the overall image SNR. This is because the SNR increases with the square root of the number of signal averages. More averages mean more data is being collected, which can be averaged out to increase the SNR, thus leading to a clearer image. For example, in magnetic resonance imaging (MRI), increasing the radiofrequency power can enhance the signal strength and improve the SNR of the resulting image. This can be achieved by increasing the number of averages or using higher coil sensitivity.
By increasing the signal strength, it becomes easier to distinguish the desired signal from the noise, leading to a clearer image with better SNR.