Using amide proton transfer-weighted MRI to non-invasively differentiate mismatch repair deficient and proficient tumors in endometrioid endometrial adenocarcinoma

Insights into Imaging

Table 1 MR imaging parameters details

Parameters	APTw	T1-weighted	T2-weighted	T2-weighted	Diffusion-weighted
Imaging acquisition	3D TSE	TSE	TSE	TSE	EPI
Orientation	Axial	Axial	Axial	Sagittal	Axial
Repetition time/echo time (ms)	7188/5.4	507/8.0	3471/100	3500/100	4656/82
Flip angle (°)	90	90	90	90	90
Field of view (mm²)	300 × 243	240 × 300	400 × 400	260 × 260	300 × 218
Matrix (frequency × phase)	120 × 96	320 × 299	400 × 400	512 × 512	100 × 72
Spatial resolution (mm²)	2.5 × 2.5	0.75 × 1.0	1.0 × 1.0	0.51 × 0.51	3.0 × 3.0
Slice thickness (mm)	5	4	3	3	4
Slice gap (mm)	0	1	0.3	0.3	1
No. of slices	9	40	41	29	25
ETL	158	4	24	32	…
EPI factor	…	…	…	…	55
SENSE factor	2	1.6	3.5	1.5	1.8
b values	…	…	…	…	0,1000
Fat suppression	SPIR	…	…	…	SPAIR
Total image time (min:s)	7:33	3:18	2:36	3:21	1:30

MR = Magnetic resonance; APTw = Amide proton transfer-weighted; TSE = Turbo spin echo; ETL = Echo train length; EPI = Echo planar imaging; SENSE = Sensitivity encoding; SPAIR = Spectral attenuation with inversion recovery; SPIR = Spectral presaturation with inversion recovery. Other key parameters for APTw imaging include 2-s long radiofrequency (RF) pulses at 2-μT power, and 9 acquisitions including 7 different frequency saturation offsets (− 4.3, − 3.5, − 2.7, 2.7, 3.5, 4.3 and − 1560 ppm) and 2 additional acquisitions with echo shifts