3 Tesla Sodium Inversion Recovery Magnetic Resonance Imaging Allows for Improved Visualization of Intracellular Sodium Content Changes in Muscular Channelopathies

    loading  Checking for direct PDF access through Ovid



To implement different sodium (23Na)-magnetic resonance imaging (MRI) contrasts at 3 Tesla and to evaluate if a weighting toward intracellular sodium can be achieved, using 2 rare muscular channelopathies as model diseases.

Materials and Methods:

Both lower legs of 6 patients with hypokalemic periodic paralysis (HypoPP), 5 patients with paramyotonia congenita (PC), and 5 healthy volunteers were examined on a 3 Tesla system with 3 different 23Na-MRI pulse sequences. HypoPP and PC are rare muscle diseases, which are well characterized by elevated myoplasmic sodium at rest and after cooling, respectively. Intra- and interindividual comparisons were performed before and after provocation of one lower leg muscle. Three different 23Na-MRI sequences were applied: (i) The total tissue sodium concentration was measured using a spin-density sequence (23Na-TSC). (ii) A T1-contrast was applied to assess whether the known changes of the intracellular sodium concentration can be visualized by T1-weighting (23Na-T1). (iii) An inversion recovery (23Na-IR) sequence was used to utmost suppress the sodium signal from extracellular or vasogenic edema. Furthermore, a potential influence of the temperature dependency of the sodium relaxation times was considered. Additionally, 1H-MRI was performed to examine potential lipomatous or edematous changes.


In HypoPP, all 23Na sequences showed significantly (P < 0.05) higher signal intensities compared with PC patients and healthy subjects. In muscles of PC patients, provocation induced a significant (P = 0.0007) increase (>20%) in the muscular 23Na-IR signal and a corresponding decrease of muscle strength. Additionally, a tendency to higher 23Na-T1 (P = 0.07) and 23Na-TSC (P = 0.07) signal intensities was observed. Provocation revealed no significant changes in 1H-MRI. In volunteers and in the contralateral, not cooled lower leg, there were no significant signal intensity changes after provocation. Furthermore, the 23Na-IR sequence allows for a suppression of signal emanating from intravascular sodium and vasogenic edema.


Our results indicate that the 23Na-IR sequence allows for a weighting toward intracellular sodium. The combined application of the 23Na-TSC and the 23Na-IR sequence enables an improved analysis of pathophysiological changes that occur in muscles of patients with muscular channelopathies.

Related Topics

    loading  Loading Related Articles