Table 1.

Error propagation due to uncertainty on ${\text{C}}_{\text{EC}}$ and ECV of muscle. On the left side the mean ${\text{C}}_{\text{IC}}$ in an ROI containing the lesion (Patient 1 in Fig. 5) is reported for different values of ${\text{C}}_{\text{EC}}$. On the right side mean ECV and ${\text{C}}_{\text{IC}}$ in the lesion are reported for different values of the muscle ECV. In the last row the mean uncertainty, defined as mean percentage variation relative to the central values, is reported. The values of ${\text{C}}_{\text{EC}}$ and muscle ECV we used in our method and the corresponding mean ${\text{C}}_{\text{IC}}$ and ECV in the lesion are highlighted in bold. Notations are: ${\text{C}}_{\text{EC}}$ extracellular sodium concentration, ${\text{C}}_{\text{IC}}$ intracellular sodium concentration, ECV extracellular volume fraction.

	Input	Output	Input	Output
	$C_{\mathit{EC}}$ (mM)	Lesion $C_{\mathit{IC}}$ (mM)	Muscle ECV	Lesion ECV	Lesion $C_{\mathit{IC}}$ (mM)
	130	30.6	0.10	0.25	33.5
	135	28.8	0.11	0.28	30.5
	140	26.8	0.12	0.30	26.8
	145	24.8	0.13	0.33	23.0
	150	22.9	0.14	0.35	19.3
Mean uncertainty	± 7%	± 14%	± 17%	± 17%	± 26%