The opacity of mineral ion-loaded bead (DC beads®) on low-keV monochromatic images from dual energy CT and T1-weighted gradient-echo MRI.

PURPOSE: To evaluate the opacity of DC beads® (DCB) loaded with mineral ions on low-keV monochromatic images from dual energy computed tomography (DECT) and T1-weighted gradient-echo (T1-GRE) MRI.

MATERIALS AND

METHODS

Fe2+ or Ca2+-loaded DCBs were prepared by mixing DCBs in 100 mM FeSO4 or CaSO4 solution and scanned by DECT from 10 min to 27 h after mixing. The Hounsfield units (HUs) of sedimented DCBs on 40-keV monochromatic images were measured. Next, we mixed DCBs in 100, 10, 5 and 1 mM FeSO4 solutions, and scanned these solutions from 15 to 120 min after mixing using a 3 T MR scanner. The signal-noise ratios (SNRs) of sedimented DCBs on T1-GRE were measured. Venous blood was scanned to compare with DCBs.

RESULTS

The CT values of DCBs in FeSO4 and CaCl2 solutions gradually increased, and were 113.3 and 43.1 HU at 27 h, respectively; that of blood was 17.8 HU. The SNR of DCB in 1 mM FeSO4 solution increased and achieved equilibrium at 120 min, and was 120.5 and higher than in the other FeSO4 solutions. The SNR of blood was 49.7.

CONCLUSION

Optimally Fe2+-loaded DCBs can be discriminated from venous blood on 40-keV monochromatic images from DECT and T1-GRE.