Magnetic susceptibility anisotropy of myocardium imaged by cardiovascular magnetic resonance reflects the anisotropy of myocardial filament α-helix polypeptide bonds

Table 3 Estimated bulk magnetic susceptibility shift differences due to electrolytes in myocardial tissue

Electrolyte	Molar susceptibility^a (CGS, cm³/mol) [68]	LV concentration^b (CGS, mol/cm³) [49]	RV concentration^b (CGS, mol/cm³) [49]	LV–RV Volume susceptibility^c difference (SI, unitless)
Electrolyte	χ_m × 10⁻⁶	c × 10⁻⁶	c × 10⁻⁶	χ_v, ppb
Ca²⁺	−10.4	0.80 ± 0.10	0.90 ± 0.27	0.01
Cl⁻	−23.4	29.07 ± 2.03	31.53 ± 2.94	0.72
K⁺	−14.9	91.04 ± 4.93	88.78 ± 5.64	−0.42
Mg²⁺	−5.0	10.49 ± 1.49	10.07 ± 1.58	−0.03
Na⁺	−6.8	32.97 ± 1.60	34.94 ± 5.64	0.17

The volume susceptibility differences between the LV and RV walls due to electrolytes are very small compared to the observed susceptibility anisotropy
^aMagnetic susceptibility values for these electrolytes are typically reported in the literature as molar susceptibilities using CGS units
^bCalculated from dog myocardium data and the density of fat-free myocardial tissue, 1.054 g/cm³ [69]
^cConversion from molar to volume susceptibility follows χ_v = χ_m c. Conversion from CGS to SI units follows χ_v(SI) = 4πχ_v(CGS)

ISSN: 1532-429X