Which pair of TE and TR would indicate that both TE and TR are long, typical of T2 weighting?

Which pair of TE and TR would indicate that both TE and TR are long, typical of T2 weighting?

• A. TE: 60 TR: 600
• B. TE: 25 TR: 1500
• C. TE: 170 TR: 1250
• D. TE: 300 TR: 1000

Answer: (D)

The main idea is that TE and TR determine image weighting: long TE and long TR together maximize T2 weighting. A long echo time means the signal is measured after more T2 decay has occurred, so tissues with different T2 times diverge more in signal. A long repetition time allows spins to partially or fully recover between pulses, reducing T1 influence and letting T2 differences dominate the image contrast. So the option that has both parameters described as long will yield a T2-weighted appearance. The other options mix short TE or short TR, which introduces T1 or proton-density weighting rather than pure T2.

The main idea is that TE and TR determine image weighting: long TE and long TR together maximize T2 weighting. A long echo time means the signal is measured after more T2 decay has occurred, so tissues with different T2 times diverge more in signal. A long repetition time allows spins to partially or fully recover between pulses, reducing T1 influence and letting T2 differences dominate the image contrast. So the option that has both parameters described as long will yield a T2-weighted appearance. The other options mix short TE or short TR, which introduces T1 or proton-density weighting rather than pure T2.