Table 4.

Sodium measurements from nine healthy participants using large and small ROIs and their association with breast density groups (≤ 50% (n = 10 breasts) and > 50% (n = 8 breasts))

	Reader 1a			Reader 2a
	Non-dense breasts	Dense breasts	p-value	Non-dense breasts	Dense breasts	p-value
Large ROI measurements
Mean TSC (mmol/L)	46.1 ± 12.2	67.6 ± 12.7	0.002	49.8 ± 11.1	73.7 ± 14.0	< 0.001
Min. TSC (mmol/L)	19.3 ± 7.7	21.8 ± 3.3	0.696	29.3 ± 6.5	31.6 ± 10.9	0.574
Max. TSC (mmol/L)	68.2 ± 16.1	100.4 ± 16.3	< 0.001	68.8 ± 16.9	99.4 ± 16.0	0.001
Mean FASC (mmol/L)	14.0 ± 5.8	21.2 ± 5.5	0.017	15.5 ± 5.8	23.2 ± 7.0	0.020
Small ROI measurements
Mean TSC (mmol/L)	61.1 ± 14.8	93.4 ± 14.7	< 0.001	63.9 ± 15.0	92.2 ± 15.3	0.001
Min. TSC (mmol/L)	54.1 ± 14.5	86.3 ± 16.5	< 0.001	58.0 ± 13.0	86.9 ± 15.6	< 0.001
Max. TSC (mmol/L)	67.5 ± 16.2	98.9 ± 14.9	< 0.001	68.6 ± 16.6	96.4 ± 16.0	0.003
Mean FASC (mmol/L)	21.1 ± 8.8	30.3 ± 11.2	0.067	20.0 ± 8.4	31.5 ± 8.9	0.012

FASC Fluid-attenuated sodium concentration, ROI Region of interest, TSC Total sodium concentration

Data are given as mean ± standard deviation. The p-value denotes the statistical difference between non-dense and dense breasts

^aThe phantom’s signal intensity and B₁ measurement measured by Reader 1 was used to minimise the effect of differences caused by phantom ROI placement that contributes to B₁-corrected measurements