Signal-to-noise ratio (SNR) in MRI can be improved by: a. Increasing

1.	Signal-to-noise ratio (SNR) in MRI can be improved by: a. Increasing the tip angle in gradient-echo sequences above the Ernst angle b. Increasing the receiver bandwidth c. Using surface coils d. Using spin–echo sequences instead of gradient-recalled echo (GRE) e. Increasing the echo time (TE)
Answer» a. False. The Ernst angle is the flip angle at which the signal is maximal for a given T₁ and repetition time (TR). Increasing the flip angle above this value would lead to a decrease in signal. b. False. SNR is inversely proportional to the square root of the bandwidth. A larger bandwidth increases the detected noise. c. True. This reduces the volume of tissue from which noise is detected. d. True. In general, spin echo gives higher signal than GRE. e. False. As the TE increases, more T₂ decay occurs resulting in a smaller signal.

Signal-to-noise ratio (SNR) in MRI can be improved by: a. Increasing the tip angle in gradient-echo sequences above the Ernst angle b. Increasing the receiver bandwidth c. Using surface coils d. Using spin–echo sequences instead of gradient-recalled echo (GRE) e. Increasing the echo time (TE)

Answer»

a. False. The Ernst angle is the flip angle at which the signal is maximal for a given T₁ and repetition time (TR). Increasing the flip angle above this value would lead to a decrease in signal.

b. False. SNR is inversely proportional to the square root of the bandwidth. A larger bandwidth increases the detected noise.

c. True. This reduces the volume of tissue from which noise is detected.

d. True. In general, spin echo gives higher signal than GRE.

e. False. As the TE increases, more T₂ decay occurs resulting in a smaller signal.

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