TABLE 2.
Relative SNR for blood and myocardium at 0.55T, and relative blood‐myocardium CNR
| Cartesian | EPI | Spiral in‐out | |||
|---|---|---|---|---|---|
| 1 | √Tsampling | SNR of any tissue | 1.00 | 1.24 | 1.42 |
| 2 | Simulation | Myocardium SNR | 1.00 | 1.26 | 1.45 |
| Blood SNR | 1.00 | 1.25 | 1.44 | ||
| CNR (blood‐myocardium) | 1.00 | 1.24 | 1.43 | ||
| 3 | Phantom measurement | Myocardium SNR | 1.00 | 1.37 | 1.52 |
| Blood SNR | 1.00 | 1.31 | 1.50 | ||
| CNR (blood‐myocardium) | 1.00 | 1.21 | 1.45 | ||
| 4 | In vivo measurement | Myocardium SNR | 1.00 | 1.50 ± 0.14 | 1.79 ± 0.21 |
| Blood SNR | 1.00 | 1.37 ± 0.17 | 1.69 ± 0.16 | ||
| CNR (blood‐myocardium) | 1.00 | 1.21 ± 0.32 | 1.58 ± 0.22 |
Notes: Values are scaled relative to the Cartesian acquisition at 0.55T. (1) SNR estimated using sampling duty cycle only; (2) SNR estimated using Bloch equation simulation; (3) SNR and CNR measured in phantom for materials with T1 and T2 similar to blood and myocardium; and (4) SNR and CNR measured in vivo in 12 healthy volunteers (reported as mean of systole and diastole measurements). CNR, contrast‐to‐noise ratio.