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standard_cest_protocols

# Standard CEST protocols

B1 definitions here are the flip angle equivalent (pure FA), thus the average B1 of a single saturation pulse. This also means that the flip angle of each saturation pulse is directly given by FA = B1·γ·t_p

t_p = duration of a single saturation pulse, t_sat = total time of the saturation pulse train

## 3T APT

### APTw_1 : APT-weighted, low DC, t_sat=1.8s (//GLINT//)

• pulse shape = Gaussian
• B1 = 2.22 µT
• n = 20
• t_p = 50 ms
• t_d = 40 ms
• ⇒ DC = 0.55 and t_sat = n*(t_p+t_d) = 1.8 s
• T_rec = 2.4/12 s (saturated/M0)

total acquisition time (depends on the readout) : approximately 3min24s for snapshot-GRE

### APTw_2 : APT-weighted, low DC, t_sat=0.8s (//HDAPTTRIO//)

• pulse shape = RECT
• B1 = 2 µT
• n = 5
• t_p = 100 ms
• t_d = 72 ms
• ⇒ DC = 0.58 and t_sat = n*(t_p+t_d) = 860 ms
• T_rec = 2 s
• measurements= 17

Δω [ppm] = -300, 4, -3.75, -3.75, -3.5, -3.5, -3.25, -3.25, -3, 3, 3.25, 3.25, 3.5, 3.5 3.75, 3.75, 4

### APTw_3 : APT-weighted, high DC, t_sat=0.8s (//HDAPT//)

• pulse shape = RECT
• B1 = 2 µT
• n = 8
• t_p = 100 ms
• t_d = 5 ms
• ⇒ DC = 0.95 and t_sat = n*(t_p+t_d) = 840 ms
• T_rec = 2 s
• measurements= 17

Δω [ppm] = -300, 4, -3.75, -3.75, -3.5, -3.5, -3.25, -3.25, -3, 3, 3.25, 3.25, 3.5, 3.5 3.75, 3.75, 4

## 3T Multi-Pool (MP) - low power - selective amide and NOE protocols

### MP_1 : low DC (//GLINT//)

• pulse shape = Gaussian
• B1 = 0.6 µT (first scan), B1 = 0.9 µT (second scan)
• n = 80
• t_p = 20.48 ms
• t_d = 20 ms
• ⇒ DC = 0.5 and t_sat = n*(t_p+t_d) = 3.2 s
• T_rec = 0 ms
• measurements = 54

Δω [ppm] = [ -300, -100, -50, -40, -30, -20, -10, -9.5, -9,-8.5,-8,-7.5,-7,-6.5,-6,-5.5,-5,-4.5,-4,-3.5,-3,-2.5,-2,-1.5,-1,-0.5,-0.25,0,0.25,0.5,1,1.5,2,2.5,3,3.5,4,4.5,5,5.5,6,6.5,7,7.5, 8,8.5,9,9.5,10,20,30,40,50,100 ]

total acquisition time (depends on the readout) : approximately 5min20s for snapshot-GRE

### MP_2 : high DC (//HD//)

• pulse shape = Gaussian
• B1 = 0.6 µT (first scan), B1 = 0.9 µT (second scan)
• n = 148
• t_p = 20 ms
• t_d = 5 ms
• ⇒ DC = 0.8 and t_sat = n*(t_p+t_d) = 3.7 s
• T_rec = 0/12 s (saturated/M0)
• measurements = 57

Δω [ppm] = 250, 200, 150, 110, 80, 60, 45, 35, 28, 22, 17, 13, 10, 7.5, 6, 5, 4.5, 4, 3.5, 3, 2.5, 2, 1.5, 1.2, 0.9, 0.7, 0.5, 0.3, 0, −0.3, −0.5, −0.7, −0.9, −1.2, −1.5, −2, −2.5, −3, −3.5, −4, −4.5, −5, −6, −7.5, −10, −13, −17, −22, −28, −35, −45, −60, −80, −110, −150, −200, −250

total acquisition time (depends on the readout) : approximately 7min34s per B1 for snapshot-GRE

## 7T Multi-Pool (MP) - low power - selective amide and NOE protocols

### MP_1 (//GUFI TH2//)

• pulse shape = Gaussian
• B1 = 0.6 µT (first scan), B1 = 0.9 µT (second scan)
• n = 120
• t_p = 15ms
• t_d = 10 ms
• ⇒ DC = 0.6 and t_sat = n*(t_p+t_d) = 3.0 s
• T_rec = 0/12 s (saturated/M0)
• measurements = 56

Δω [ppm] = [-300 -100 -50 -20 -12 -9 -7.25 -6.25 -5.5 -4.7 -4 -3.3 -2.7 -2 -1.7 -1.5 -1.1 -0.9 -0.6 -0.4 0 0.4 0.6 0.95 1.1 1.25 1.4 1.55 1.7 1.85 2 2.15 2.3 2.45 2.6 2.75 2.9 3.05 3.2 3.35 3.5 3.65 3.8 3.95 4.1 4.25 4.4 4.7 5.25 6.25 8 12 20 50 100 -300 ]

total acquisition time (depends on the readout) : approximately 6:40s per B1 for snapshot-GRE