Table 2. Summary of the cross-sectional age-corrected QSM observations. Statistical significance measured with Wilcoxon rank sum test (one-tailed).

ROI	QSM (ppb)			Baseline ALS vs. control subjects
	Control subjects, mean ± SEM	Baseline ALS, mean ± SEM		P value	Cohen’s d
Left primary motor area (anterior)	27.8±0.9	29.6±1.0		0.12	0.57
Right primary motor area (anterior)	29.7±1.1	33.0±0.9		0.02*	0.92
Left primary motor area (posterior)	27.0±0.8	30.2±1.2		0.02*	0.9
Right primary motor area (posterior)	28.3±0.8	30.3±1.1		0.09	0.58
Left pre-motor area	23.1±0.6	24.4±0.8		0.23	0.50
Right pre-motor area	23.2±0.5	24.6±1.0		0.09	0.47

QSM, quantitative susceptibility mapping; ALS, amyotrophic lateral sclerosis; SEM, standard error of the mean; ROI, region of interest.