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23Na MRI: Inter-reader reproducibility of Normal Fibroglandular Sodium Concentration Measurements at 3T

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Arponen, Otso 
McLean, Mary 
Nanaa, Muzna 
Manavaki, Roido 


Purpose: To study the reproducibility of sodium-23 Magnetic Resonance Imaging (23Na MRI) measurements in healthy volunteers’ breast tissue. Methods: Using a dual-tuned bilateral 23Na/1H breast coil at 3T MRI, high-resolution 23Na MRI 3D cones sequences were used to quantify total and fluid-attenuated sodium concentration (TSC and FASC, respectively). B1-corrected TSC and FASC maps were created. Two readers manually measured TSC mean, minimum and maximum and mean FASC concentrations using two sampling methods (large (LROI) and small (SROI) regions of interest encompassing fibroglandular tissue (FGT) and the highest signal area at the level of the nipple, respectively). The reproducibility of the measurements and correlations between density, age and FGT apparent diffusion coefficient (ADC) values were evaluated.

Results: Nine healthy volunteers were included. The inter-reader reproducibility of TSC and FASC using SROIs and LROIs was excellent (intra-class coefficient range: 0.945 -0.979, P < 0.001), except for the minimum TSC LROI measurements (P = 0.369). The mean/minimum LROI TSC and mean LROI FASC values were lower than the respective SROI values (P < 0.001); the maximum LROI TSC values were higher than the SROI TSC values (P = 0.09). TSC correlated inversely with age and FGT ADCs. The mean and maximum FGT TSC and FASC concentrations were higher in dense breasts in comparison to non-dense breasts (P < 0.05).

Conclusions: The chosen sampling method and the selected descriptive value affect the measured TSC and FASC concentrations, although the inter-reader reproducibility of the measurements is in general excellent.



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European radiology experimental

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This work was funded by Cancer Research UK (A25922). The authors would also like to acknowledge the National Institute of Health Research (NIHR) Cambridge Biomedical Research Centre (BRC-1215-20014). OA is the recipient of grants from the Osk. Huttunen Foundation, Sigrid Jusélius Foundation, Relander Foundation, Finnish Medical Foundation, Cancer Foundation Finland, and Orion Research Foundation. The funders had no role in the design of this study, its execution, analyses, interpretation of the data, or the decision to publish the results.