Magnetic susceptibility and R2* of myocardial reperfusion injury at 3T and 7T

Moon, Brianna F.; Iyer, Srikant Kamesh; Josselyn, Nicholas; Hwuang, Eileen; Swago, Sophia; Keeney, Samuel; Castillero, Estíbaliz; Ferrari, Giovanni; Pilla, James J.; Gorman, Joseph H.; Gorman, Robert C.; Tschabrunn, Cory M.; Shou, Haochang; Matthai, William H.; Wehrli, Félix W.; Ferrari, Victor A.; Han, Yuchi; Litt, Harold; Witschey, Walter R.

doi:10.1002/mrm.28955

Cited by 5 publications

(1 citation statement)

References 55 publications

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“…To the best of our knowledge, observations relating microcirculatory heterogeneity, bleeding during acute infarction and/or remodeling as monitored by

contrast have not been reported so far and need to be investigated systematically in a larger study in the future. Moon and coworkers have already made some attempts towards that direction using ex-vivo imaging, but their study was limited to the early phase (2–4 h) of myocardial infarction ( 108 ).…”

Section: Discussionmentioning

confidence: 99%

Ultra-high field cardiac MRI in large animals and humans for translational cardiovascular research

Schreiber,

Lohr,

Baltes

et al. 2023

Front. Cardiovasc. Med.

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A key step in translational cardiovascular research is the use of large animal models to better understand normal and abnormal physiology, to test drugs or interventions, or to perform studies which would be considered unethical in human subjects. Ultrahigh field magnetic resonance imaging (UHF-MRI) at 7 T field strength is becoming increasingly available for imaging of the heart and, when compared to clinically established field strengths, promises better image quality and image information content, more precise functional analysis, potentially new image contrasts, and as all in-vivo imaging techniques, a reduction of the number of animals per study because of the possibility to scan every animal repeatedly. We present here a solution to the dual use problem of whole-body UHF-MRI systems, which are typically installed in clinical environments, to both UHF-MRI in large animals and humans. Moreover, we provide evidence that in such a research infrastructure UHF-MRI, and ideally combined with a standard small-bore UHF-MRI system, can contribute to a variety of spatial scales in translational cardiovascular research: from cardiac organoids, Zebra fish and rodent hearts to large animal models such as pigs and humans. We present pilot data from serial CINE, late gadolinium enhancement, and susceptibility weighted UHF-MRI in a myocardial infarction model over eight weeks. In 14 pigs which were delivered from a breeding facility in a national SARS-CoV-2 hotspot, we found no infection in the incoming pigs. Human scanning using CINE and phase contrast flow measurements provided good image quality of the left and right ventricle. Agreement of functional analysis between CINE and phase contrast MRI was excellent. MRI in arrested hearts or excised vascular tissue for MRI-based histologic imaging, structural imaging of myofiber and vascular smooth muscle cell architecture using high-resolution diffusion tensor imaging, and UHF-MRI for monitoring free radicals as a surrogate for MRI of reactive oxygen species in studies of oxidative stress are demonstrated. We conclude that UHF-MRI has the potential to become an important precision imaging modality in translational cardiovascular research.

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“…To the best of our knowledge, observations relating microcirculatory heterogeneity, bleeding during acute infarction and/or remodeling as monitored by

Section: Discussionmentioning

confidence: 99%

Ultra-high field cardiac MRI in large animals and humans for translational cardiovascular research

Schreiber,

Lohr,

Baltes

et al. 2023

Front. Cardiovasc. Med.

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T2* assessment of the three coronary artery territories of the left ventricular wall by different monoexponential truncation methods

Triadyaksa

Overbosch

Oudkerk

et al. 2022

Magn Reson Mater Phy

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Objectives This study aimed at evaluating left ventricular myocardial pixel-wise T2* using two truncation methods for different iron deposition T2* ranges and comparison of segmental T2* in different coronary artery territories. Material and methods Bright blood multi-gradient echo data of 30 patients were quantified by pixel-wise monoexponential T2* fitting with its R2 and SNR truncation. T2* was analyzed at different iron classifications. At low iron classification, T2* values were also analyzed by coronary artery territories. Results The right coronary artery has a significantly higher T2* value than the other coronary artery territories. No significant difference was found in classifying severe iron by the two truncation methods in any myocardial region, whereas in moderate iron, it is only apparent at septal segments. The R2 truncation produces a significantly higher T2* value than the SNR method when low iron is indicated. Conclusion Clear T2* differentiation between the three coronary territories by the two truncation methods is demonstrated. The two truncation methods can be used interchangeably in classifying severe and moderate iron deposition at the recommended septal region. However, in patients with low iron indication, different results by the two truncation methods can mislead the investigation of early iron level progression.

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Radiofrequency antenna concepts for human cardiac MR at 14.0 T

Nurzed

Kuehne²,

Aigner

et al. 2023

Magn Reson Mater Phy

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Objective To examine the feasibility of human cardiac MR (CMR) at 14.0 T using high-density radiofrequency (RF) dipole transceiver arrays in conjunction with static and dynamic parallel transmission (pTx). Materials and methods RF arrays comprised of self-grounded bow-tie (SGBT) antennas, bow-tie (BT) antennas, or fractionated dipole (FD) antennas were used in this simulation study. Static and dynamic pTx were applied to enhance transmission field (B1+) uniformity and efficiency in the heart of the human voxel model. B1+ distribution and maximum specific absorption rate averaged over 10 g tissue (SAR10g) were examined at 7.0 T and 14.0 T. Results At 14.0 T static pTx revealed a minimum B1+ROI efficiency of 0.91 μT/√kW (SGBT), 0.73 μT/√kW (BT), and 0.56 μT/√kW (FD) and maximum SAR10g of 4.24 W/kg, 1.45 W/kg, and 2.04 W/kg. Dynamic pTx with 8 kT points indicate a balance between B1+ROI homogeneity (coefficient of variation < 14%) and efficiency (minimum B1+ROI > 1.11 µT/√kW) at 14.0 T with a maximum SAR10g < 5.25 W/kg. Discussion MRI of the human heart at 14.0 T is feasible from an electrodynamic and theoretical standpoint, provided that multi-channel high-density antennas are arranged accordingly. These findings provide a technical foundation for further explorations into CMR at 14.0 T.

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Magnetic susceptibility and R2* of myocardial reperfusion injury at 3T and 7T

Cited by 5 publications

References 55 publications

Ultra-high field cardiac MRI in large animals and humans for translational cardiovascular research

Ultra-high field cardiac MRI in large animals and humans for translational cardiovascular research

T2* assessment of the three coronary artery territories of the left ventricular wall by different monoexponential truncation methods

Radiofrequency antenna concepts for human cardiac MR at 14.0 T

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