Table 2.

APT imaging technique of the included studies using MTR asymmetry (at 3.5 ppm) on MRI systems.

Author (year)	Hardware	Pulse sequence
		RF saturationapproach	RF saturationparameters		Readout	Acquisitionprotocol
Jiang S S et al. (2019) (11)	Philips Achieva 3.0 T	Pulse train	tp = 200 ms, td = 10 ms, n = 4, DCsat = 95%, Tsat = 830 ms, B1 = 2 μT	3D-GRASE		Z-spectrum
Liu J et al. (2020) (19)	GE, Discovery MR750 3.0 T	Pulse train	tp = 400 ms, td = 0 ms, n = 3, DCsat = 100%, Tsat = 1.2 s, B1 = 1.5 μT	Single-slice, SE-EPI		Z-spectrum
Ma B et al. (2016) (15)	Philips Achieva 3.0 T	Pulse train	tp = 200 ms, td = 10 ms, n = 4, DCsat = 95%, Tsat = 830 ms, B1 = 2 μT	3D-GRASE		Z-spectrum
Paprottka K J et al. (2021) (17)	Philips Achieva or Ingenia 3.0 T	Time-interleaved pTX	tp = 50 ms, td = 0 ms, n = 40, DCsat = 100%, Tsat = 2 s, B1 = 2 μT	3D-FSE		6-offset
Park K J et al. (2016) (16)	Philips Achieva 3.0 T	Time-interleaved pTX	tp = 70 ms, td = 70 ms, n = 30, DCsat = 50%, Tsat = 4.2 s, B1 = 1 μT	3D-GRE		Z-spectrum
Park Y W et al. (2021) (18)	Philips Achieva or Ingenia 3.0 T	Pulse train	tp = 200 ms, td = 0 ms, n = 4, DCsat = 100%, Tsat = 800 ms, B1 = 2 μT		3D-GRASE	6-offset

pTX, parallel transmit; t_p, individual pulse element duration in a pulse train; t_d, interpulse delay; n, number of pulse element-delay repetitions; DCsat, saturation duty cycle (= t_p/[t_p + t_d]); Tsat, total RF saturation time; B1, RF saturation field strength.

Z-spectrum, normalized water saturation signal (S_sat/S₀) as a function of frequency offset relative to the water resonance, where S_sat and S₀ are water signal intensities with and without RF saturation, respectively; 6-offset, APT MRI saturation at the saturation frequency offsets ( ± 3.0, ± 3.5, ± 4.0 ppm) from water and without saturation, for example.

SE, spin-echo acquisition; FSE, fast spin echo; EPI, echo planar imaging; GRE, gradient echo; GRASE, gradient and spin-echo acquisition.