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Standard CEST protocols

We want to hint that there is a more detailed and growing site for standard protocols based on pulseq here https://github.com/kherz/pulseq-cest

We recommend to follow this site in the future for standardization of protocols.

below you find the old information, which will at some point be removed for the sake of pulseq-cest.

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