Feasibility of complementary spatial modulation of magnetization tagging in the rat heart after manganese injection

Abstract

It has been shown that manganese-enhanced MRI (MEMRI) can safely depict the myocardial area at risk in models of coronary occlusion-reperfusion for at least 2 h after reperfusion. To achieve this, a solution of MnCl(2) is injected during coronary occlusion. In this model, the regional function quantification deficit of the stunning phase cannot be assessed before contrast injection using MR tagging. The relaxation effects of manganese (which remains in normal cardiac myocytes for several hours) may alter the tags by increasing tag fading and hence the quality of strain measurement. Therefore, we evaluated the feasibility of cardiac MR tagging after manganese injection in normal rats. Six normal Sprague-Dawley rats were imaged in vivo using complementary spatial modulation of magnetization (C-SPAMM) at 1.5 T, before and 15 min after intraperitoneal injection of MnCl(2) solution (~17.5 micromol kg(-1)). The contrast-to-noise ratio of the tag pattern increased significantly (P < 0.001) after injection and remained comparable to the control scan in spite of the higher myocardial relaxation rate caused by the presence of manganese. The measurements of circumferential strain obtained from harmonic phase imaging analysis of the tagged images after MnCl(2) injection did not differ significantly from the measurements before injection in the endocardial, mid-wall, and epicardial regions. In particular, the transmural strain gradient was preserved. Thus, our study suggests that MR tagging could be used in combination with MEMRI to study the acute phase of coronary artery disease.

Novel insight into the detailed myocardial motion and deformation of the rodent heart using high-resolution phase contrast cardiovascular magnetic resonance

“…That study also reported, in accordance with our findings, prominent heterogeneity in the Sc in healthy rat hearts. Our results are also in excellent agreement with other studies on global myocardial Sc in rat hearts [32,33]. …”

Myocardial infarction quantification with Manganese‐Enhanced MRI (MEMRI) in mice using a 3T clinical scanner

“…No correlation was found, either for sham, or for control groups due to the lack of dispersion of wall thickening and normalized signal intensity values. However, even if these results depicted the contraction deficit relative to infarction, an important improvement in function evaluation would be to perform assessment of intramyocardial strains, either by displacement-encoded imaging with stimulated echos (DENSE) (34) or with myocardial tagging, as was previously reported in rat myocardium (35) and also in mice (36,37). Moreover, it has been shown that myocardial tagging can also provide accurate EF measurement (38), so both regional and global function can be acquired in one single acquisition.…”

Manganese‐guided cellular MRI of human embryonic stem cell and human bone marrow stromal cell viability

“…Luciferase‐transfected hESC (hESC‐luc + , H9 WiCell Distribution Lot, National Stem Cell Bank c/o WiCell Research Institute, Madison, WI) was employed for this experiment (courtesy of Dr. Joseph Wu) (15). These cells were maintained using one of two feeder systems: 1) irradiated mouse embryonic fibroblasts (mEF) feeder layer with hESC growth media (80% knockout Dulbecco modified Eagle medium [Invitrogen, Carlsbad, CA], 20% serum replacement [Invitrogen], 0.1 mM 2‐mercaptoethanol [Sigma, St. Louis, MO], 0.1 mM nonessential amino acids [Invitrogen], 1% penicillin/streptomycin [Invitrogen], 2 mM L‐glutamine [Invitrogen] with rh‐bFGF [R&D Systems, Minneapolis, MN] 4 ng/mL), and 2) growth factor reduced Matrigel (BD Biosciences, San Jose, CA) without mEF feeder layer using growth media described above and higher concentration of rh‐bFGF (20 ng/mL).…”