Table 1:

Protocols of MR image acquisition

Protocol	MRI system	RF coil	TR (ms)	TE (ms)	TI (ms)	Voxel size (mm)	Flip angle
1	Trio	Quadrature knee	2500	4.38	1100	0.5 × 0.5 × 0.5	12
2	TimTrio	Quadrature knee (Tim)	2500	3.86	1100	0.5 × 0.5 × 0.5	12
3	Trio	8-Channel knee array	2500	4.38	1100	0.5 × 0.5 × 0.5	12
4	TrioTim	15-Channel knee array	2500	3.86	1100	0.5 × 0.5 × 0.5	12

RF, Radiofrequency. As indicated in the table, the ONPRC MRI system was upgraded throughout the study and different RF coils were used to enhance the signal-to-noise ratio. The parameters of MR image acquisition were adjusted accordingly.