Feasibility of 7 T 39K/23Na Magnetic Resonance Imaging for assessing muscular ion balance in hypokalemic periodic paralysis

Mathy C, Nagel AM, Türk M, Stuprich C, Gerhalter T, Marty B, Bickelhaupt S, Laun FB, Dörfler A, Uder M, Bäuerle T, Heiß R, Weber MA, Gast L (2025)


Publication Type: Journal article

Publication year: 2025

Journal

DOI: 10.1097/RLI.0000000000001188

Abstract

Objectives Recently introduced potassium-39-(39K)-MRI provides a noninvasive approach to assess typically high intracellular K+-levels and can be combined with sodium-23-(23Na)-MRI. The aim of this study was to evaluate 39K/23Na muscle ion homeostasis in hypokalemic periodic paralysis (HypoPP), a rare muscular ion channelopathy, using 7 T MRI. Materials and Methods Lower legs of patients with HypoPP and healthy controls were prospectively examined between August 2022 and July 2023 (case-control study). Scanning protocol at 3 T included T1-weighted, T2-weighted STIR sequences, a 6-point-Dixon-type gradient echo and a T2-mapping sequence. 39K/23Na data were acquired at 7 T using acquisition-weighted Stack-of-Stars sequences. Apparent tissue 39K/23Na concentrations (aTPC/aTSC) were calculated after correcting for partial-volume and relaxation effects and corrected for proton-density fat-fractions to account for fatty replacement. A 23Na-inversion-recovery (23Na-IR) sequence served to introduce a stronger intracellular weighting. Differences in central tendency between the HypoPP and control groups and correlations were analyzed. Results Thirteen HypoPP-participants and 13 controls were included. Extent of fatty replacement/edema-like changes varied highly with the gastrocnemius medialis muscle most affected. The HypoPP group showed significantly increased aTSC in all 7 analyzed muscles and decreased aTPC in 3 specific muscles. Across all muscles, the mean aTSC was higher in the HypoPP group (median: 33.4 vs 22.5 mM, mean ± SD: 34.3 ± 6.8 vs 21.0 ± 4.8 mM, P < 0.001), whereas the mean aTPC was lower (98.7 vs 109.0 mM, 97.9 ± 12.0 vs 108.7 ± 10.4 mM, P = 0.02). The 23Na-IR signal was strongly correlated with aTSC (r = 0.77, P < 0.001). Conclusions Combined 39K/23Na MRI at 7 T demonstrated alterations of sodium and potassium ion homeostasis in HypoPP. These findings could be helpful for a better pathophysiological understanding of HypoPP and may aid in future studies to assess disease extent or monitor treatment efficacy.

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APA:

Mathy, C., Nagel, A.M., Türk, M., Stuprich, C., Gerhalter, T., Marty, B.,... Gast, L. (2025). Feasibility of 7 T 39K/23Na Magnetic Resonance Imaging for assessing muscular ion balance in hypokalemic periodic paralysis. Investigative Radiology. https://doi.org/10.1097/RLI.0000000000001188

MLA:

Mathy, Claudius, et al. "Feasibility of 7 T 39K/23Na Magnetic Resonance Imaging for assessing muscular ion balance in hypokalemic periodic paralysis." Investigative Radiology (2025).

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