Table 1.
Comparison of the CEST-MRF determined L-Arg concentrations, amine proton chemical exchange rates and water T1 relaxation times with the known concentrations, QUESP measured exchange rates, and variable TR (VTR) measured T1 relaxation times, respectively, for the various L-Arg phantoms. The mean ±standard deviation was calculated for the ROI drawn around each vial.
| pH | [L-Arg] (mM) | kex (Hz) | Water T1 (ms) | |||
|---|---|---|---|---|---|---|
|
| ||||||
| known | MRF | QUESP | MRF | VTR | MRF | |
| 4.05 | 25 | 26.1±6.7 | 193.9±57.0 | 156.2±44.5 | 2492.8±51.8 | 2709.2±143.9 |
| 4.08 | 50 | 49.4±7.0 | 183.7±21.7 | 170.7±23.9 | 2802.9±60.0 | 2885.7±154.3 |
| 4.01 | 100 | 84.0±9.6 | 200.4±30.4 | 196.2±21.4 | 2628.3±52.6 | 2949±152.0 |
| 4.04 | 50 | 51.7±6.8 | 204.5±31.1 | 200.4±29.4 | 2669.7±55.7 | 2809.6±141.6 |
| 4.46 | 50 | 53.1±5.2 | 281.8±28.9 | 268.5±31.5 | 2608.3±50.2 | 2847.6±159.1 |
| 4.99 | 50 | 50.3±3.2 | 444.3±33.0 | 446.0±34.3 | 2854.1±58.7 | 2919.5176.2 |
| 5.05 | 25 | 26.9±2.7 | 384.2±61.1 | 375.5±53.6 | 2551.9±51.73 | 2500±0 |
| 5.02 | 50 | 55.1±3.4 | 420.9±45.3 | 392.4±39.5 | 2757.9±59.1 | 2507.7±34.6 |
| 5.02 | 100 | 110.0±6.4 | 437.8±82.7 | 424.5±30.7 | 2573.6±48.1 | 2721±197.3 |
| 4.99 | 50 | 50.4±2.9 | 444.1±86.7 | 491.5±40.9 | 2825.7±52.1 | 3073.2±244.6 |
| 5.43 | 50 | 62.7±3.6 | 670.0±120.8 | 692.6±50.6 | 2594.5±50.1 | 3117.4±229.3 |
| 5.96 | 50 | 57.9±3.4 | 1066.8±148.7 | 1219.4±65.0 | 2621.6±48.2 | 3164.4±222.3 |