Effects of iodinated contrast on various magnetic resonance imaging sequences and field strength: Implications for characterization of hemorrhagic transformation in acute stroke therapy

Effects of contrast agents on relaxation properties of 31P metabolites

“…While iopamidol is a widely used CT contrast agent not typically used in MRI, it has slow clearance kinetics, and hence, can still be present in the body 24 hours after a contrast enhanced CT scan. We have observed significant shortening of both T 1 and T 2 relaxation times in saline and PBS solutions, which is in good agreement with literature 12,14,28 . However, these effects are highly concentration dependent, with negligible impact in tissues when the contrast agent is diluted 13,29 .…”

“…We have observed significant shortening of both T 1 and T 2 relaxation times in saline and PBS solutions, which is in good agreement with literature. 12,14,28 However, these effects are highly concentration dependent, with negligible impact in tissues when the contrast agent is diluted. 13,29 Our results support this hypothesis, as after adding the prescribed clinical dose of Iopamidol (~2% concentration of contrast agent), it was not possible to observe any effect on the blood 1 H relaxation times.…”

Signal Intensity and Volume of Pituitary and Thyroid Glands in Preterm and Term Infants

“…Between 30 to 42 gestational weeks, there is a progressive increase in iodine, T4 and T3 contents, and thyroid gland hormone reserves increases 3‐ to 4‐fold 1,25 . Abundant thyroglobulin and iodine in the colloid cysts of the thyroid gland may contribute to T 1 ‐shortening effects 26‐28 . The increase in T mean /cord and T max /cord seen in this study may represent an increase in protein and iodine concentrations in thyroid gland.…”

Variable MR and pathologic patterns of hemorrhage after iodinated contrast infusion in MCA occlusion/reperfusion model

“…In a test-tube phantom analysis before embarking on this study, we documented a T2-shortening (T2 hypointensity) effect of iodixanol and iopamidol. This hypointensity was more conspicuous on T2-WI than GRE at both 1.5 and 3.0 T 17. Thus, whereas HT is characterized by GRE hypointensity or susceptibility effect,18 IRCM may be distinguished from HT owing to its less conspicuous GRE hypointensity/susceptibility.…”

“…Class II signal (T2 hypointensity with no GRE hypointensity), supporting IRCM deposition rather than hemorrhagic changes, was more common in the IRCM group than with saline. Although many potential explanations for observed differences in HT between IRCM subgroups have been previously entertained (eg, osmolality, coagulative, blood–brain barrier disruption, hydrodynamic/viscosity,20–22 and/or molecular size differences),10 23 24 the influence of IRCM use on the amount and type of HT with reperfusion remains incompletely understood 17 25–27. The findings here suggest less HT in the iodixanol subgroup, possibly related to larger molecular size and less leakage across the blood–brain barrier, or may also reflect a hydrodynamic effect of its viscous macromolecular properties.…”