Dynamic Field Mapping and Motion Correction Using Interleaved Double Spin-Echo Diffusion MRI

Magnetic Resonance in Med

Jackson

et al. 2018

Self Cite

Purpose To investigate, visualize and quantify the physiology of the human placenta in several dimensions ‐ functional, temporal over gestation, and spatial over the whole organ. Methods Bespoke MRI techniques, combining a rich diffusion protocol, anatomical data and T2* mapping together with a multi‐modal pipeline including motion correction and extracted quantitative features were developed and employed on pregnant women between 22 and 38 weeks gestational age including two pregnancies diagnosed with pre‐eclampsia. Results A multi‐faceted assessment was demonstrated showing trends of increasing lacunarity, and decreasing T2* and diffusivity over gestation. Conclusions The obtained multi‐modal acquisition and quantification shows promising opportunities for studying evolution, adaptation and compensation processes.

Section: Discussionmentioning

confidence: 89%

Section: Discussionmentioning

confidence: 99%

Multi‐modal functional MRI to explore placental function over gestation

Magnetic Resonance in Med

Jackson

et al. 2018

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“…For the remaining four scans we used a protocol with interspersed high and low b ‐value slices (scan duration: 4 min 1 s). The latter protocol aims to improve the suitability of the data for subsequent respiratory motion correction in the future.…”

Section: Methodsmentioning

confidence: 99%

Placenta microstructure and microcirculation imaging with diffusion MRI

Magnetic Resonance in Med

McCabe

et al. 2017

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PurposeTo assess which microstructural models best explain the diffusion‐weighted MRI signal in the human placenta.MethodsThe placentas of nine healthy pregnant subjects were scanned with a multishell, multidirectional diffusion protocol at 3T. A range of multicompartment biophysical models were fit to the data, and ranked using the Bayesian information criterion.ResultsAnisotropic extensions to the intravoxel incoherent motion model, which consider the effect of coherent orientation in both microvascular structure and tissue microstructure, consistently had the lowest Bayesian information criterion values. Model parameter maps and model selection results were consistent with the physiology of the placenta and surrounding tissue.ConclusionAnisotropic intravoxel incoherent motion models explain the placental diffusion signal better than apparent diffusion coefficient, intravoxel incoherent motion, and diffusion tensor models, in information theoretic terms, when using this protocol. Future work will aim to determine if model‐derived parameters are sensitive to placental pathologies associated with disorders, such as fetal growth restriction and early‐onset pre‐eclampsia. Magn Reson Med 80:756–766, 2018. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

“…Our approach breaks with this traditional paradigm by changing the diffusion encoding per slice 37 . By interleaving N i different diffusion encodings within the TR (Fig.…”

Section: Methodsmentioning

confidence: 99%

“…The order of the chosen N i encodings is not relevant for the ability to obtain accelerated IR-dMRI scans, it was, however, chosen such that the low-b volumes are maximally spread over time to enhance the potential for further motion correction 37 .…”

Section: Methodsmentioning

confidence: 99%

Integrated and efficient diffusion-relaxometry using ZEBRA

Christiaens

et al. 2018

Sci Rep

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100

118

The emergence of multiparametric diffusion models combining diffusion and relaxometry measurements provides powerful new ways to explore tissue microstructure, with the potential to provide new insights into tissue structure and function. However, their ability to provide rich analyses and the potential for clinical translation critically depends on the availability of efficient, integrated, multi-dimensional acquisitions. We propose a fully integrated sequence simultaneously sampling the acquisition parameter spaces required for T1 and T2* relaxometry and diffusion MRI. Slice-level interleaved diffusion encoding, multiple spin/gradient echoes and slice-shuffling are combined for higher efficiency, sampling flexibility and enhanced internal consistency. In-vivo data was successfully acquired on healthy adult brains. Obtained parametric maps as well as clustering results demonstrate the potential of the technique to provide eloquent data with an acceleration of roughly 20 compared to conventionally used approaches. The proposed integrated acquisition, which we call ZEBRA, offers significant acceleration and flexibility compared to existing diffusion-relaxometry studies, and thus facilitates wider use of these techniques both for research-driven and clinical applications.