Table 2.

Technical characteristics of the studies included in the R2^* meta-analysis.

References	Magnetic field	MRI machine	Method	ROIs drew in	No. echoes	Voxel size
Ordidge et al. (22)	3 T	Magnex Scientific Ltd.	T2*	T2* weighted	6	N/A
Graham et al. (9)	1.5 T	Marconi Medical Systems	R2*	T2 weighted	6	0.9 × 0.9 × 2.5
Martin et al. (28)	3 T	Magnex Scientific Ltd.	R2*	T2* weighted	6	2.3 × 2.3 × 5.0
Baudrexel et al. (32)	3 T	Siemens	T2*	T1 map	8	1.0 × 1.0 × 2.0
Péran et al. (29)	3 T	Siemens	R2*	T2* weighted	6	1.8 × 1.8 × 1.8
Focke et al. (37)	3 T	Siemens	R2*	T1 MPRAGE + MT	5	1.7 × 1.7 × 1.7
Du et al. (20)	3 T	Siemens	R2*	T2 weighted	6	1.0 × 1.0 × 1.0
Bunzeck et al. (33)	3 T	Siemens	R2*	MT	6	1.0 × 1.0 × 1.0
Rossi et al. (23)	3 T	Siemens	R2*	T2* map	5	0.6 × 0.6 × 4.0
Ulla et al. (13)	1.5 T	Siemens	R2*	T2* weighted	6	2.2 × 2.2 × 2.5
Lewis et al. (38)	3 T	Siemens	R2*	T2 weighted	6	1.0 × 1.0 × 1.0
Barbosa et al. (39)	3 T	Philips	R2*	QSM	4	0.5 × 0.5 × 2.0
He et al. (31)	3 T	GE	R2*	QSM	8	0.5 × 0.5 × 2.0
Murakami et al. (40)	3 T	GE	R2*	R2* map	11	1.5 × 2.5 × 1.5
Pyatigorskaya et al. (8)	3 T	Siemens	R2*	T2 weighted	6	2.0 × 2.0 × 2.0
Reimão et al. (26)	3 T	Philips	T2*	Spin-echo T1 neuromelanin sensitive	7	1.2 × 0.9 × 4.0
Wieler et al. (41)	3 T	Magnex Scientific Ltd.	R2*	T2* weighted	6	2.3 × 2.3 × 5.0
Guan et al. (30)	3 T	GE	R2*	QSM	8	0.8 × 0.8 × 2.8
Hopes et al. (10)	3 T	Philips	R2*	T2* weighted	15	2.0 × 2.0 × 2.0
Isaias et al. (12)	3 T	Philips	R2*	T2* weighted	2	1 × 1 × 1
Langkammer et al. (42)	3 T	Siemens	R2*	QSM	6	0.9 × 0.9 × 2.0
Du et al. (21)	3 T	Siemens	R2*	T2 weighted	8	0.9 × 0.9 × 2.0
Langley et al. (13)	3 T	Siemens	R2*	T2* weighted	6	0.5 × 0.5 × 1
Pesch et al. (16)	3 T	Philips	R2*	3D T1 weighted	N/A	1.5 × 1.5 × 1.5
Ghassaban et al. (44)	3 T	GE	R2*	QSM	N/A	0.86 × 0.86 × 1
Arribarat et al. (11)	3 T	Siemens	R2*	T2 weighted	6	1.8 × 1.8 × 1.8
Li et al. (14)	3 T	Siemens	R2*	QSM	8	0.63 × 0.63 × 2.0