Accelerating acquisition strategies for low-frequency conductivity imaging using MREIT

Song, Yizhuang; Seo, Jin Keun; Chauhan, Munish; Indahlastari, Aprinda; Kumar, Neeta Ashok; Sadleir, Rosalind

doi:10.1088/1361-6560/aaa8d2

Cited by 10 publications

(7 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Because the sequences used here involved MREIT acquisitions of approximately 18 minutes each, faster sequences must be used to avoid fatiguing subjects. We have now developed echo planar imaging (EPI) MR methods that can be used to sample brain information more rapidly [48], and introduced new undersampling techniques [49]. In addition, new fast multi-band SENSE imaging techniques [50] should allow more rapid sampling of the brain.…”

Section: Discussionmentioning

confidence: 99%

Low-Frequency Conductivity Tensor Imaging of the Human Head <italic>In Vivo</italic> Using DT-MREIT: First Study

Chauhan

Indahlastari

Kasinadhuni

et al. 2018

IEEE Trans. Med. Imaging

Self Cite

View full text Add to dashboard Cite

We present the first in vivo images of anisotropic conductivity distribution in the human head, measured at a frequency of approximately 10 Hz. We used magnetic resonance electrical impedance tomography techniques to encode phase changes caused by current flow within the head via two independent electrode pairs. These results were then combined with diffusion tensor imaging data to reconstruct full anisotropic conductivity distributions in 5-mm-thick slices of the brains of two participants. Conductivity values recovered in this paper were broadly consistent with literature values. We anticipate that this technique will be of use in many areas of neuroscience, most importantly in functional imaging via inverse electroencephalogram. Future studies will involve pulse sequence acceleration to maximize brain coverage and resolution.

show abstract

Section: Discussionmentioning

confidence: 99%

Low-Frequency Conductivity Tensor Imaging of the Human Head <italic>In Vivo</italic> Using DT-MREIT: First Study

Chauhan

Indahlastari

Kasinadhuni

et al. 2018

IEEE Trans. Med. Imaging

Self Cite

View full text Add to dashboard Cite

show abstract

“…However, it would be desirable to increase the temporal resolution of images. In future experiments, we plan to use EPI sequences (Chauhan et al, 2017) combined with undersampling (Song et al, 2016b) to assess activity at speeds similar to BOLD fMRI.…”

Section: Discussionmentioning

confidence: 99%

Direct detection of neural activity in vitro using magnetic resonance electrical impedance tomography (MREIT)

Sadleir

Falgas

et al. 2017

NeuroImage

View full text Add to dashboard Cite

We describe a sequence of experiments performed in vitro to verify the existence of a new magnetic resonance imaging contrast — Magnetic Resonance Electrical Impedance Tomography (MREIT) —sensitive to changes in active membrane conductivity. We compared standard deviations in MREIT phase data from spontaneously active Aplysia abdominal ganglia in an artificial seawater background solution (ASW) with those found after treatment with an excitotoxic solution (KCl). We found significant increases in MREIT treatment cases, compared to control ganglia subject to extra ASW. This distinction was not found in phase images from the same ganglia using no imaging current. Further, significance and effect size depended on the amplitude of MREIT imaging current used. We conclude that our observations were linked to changes in cell conductivity caused by activity. Functional MREIT may have promise as a more direct method of functional neuroimaging than existing methods that image correlates of blood flow such as BOLD fMRI.

show abstract

“…There are several technical issues which need to be carefully considered in developing practical clinical applications of MREIT, with a key issue being the need to improve acquisition efficiency while maintaining data quality. One approach to accelerate MREIT data acquisition is to skip phase encoding steps and reconstruct B z images from undersampled data (Song et al 2016, Song et al 2017, Song et al 2018. Since use of high MREIT imaging currents may produce undesirable nerve stimulation effects Woo 2014, Sadleir et al 2019) another consideration is acquiring high signal-to-noise ratio (SNR) B z data without using larger electric currents.…”

Section: Introductionmentioning

confidence: 99%

Low frequency conductivity reconstruction based on a single current injection via MREIT

Song¹,

Sajib²,

Wang³

et al. 2020

Phys. Med. Biol.

Self Cite

View full text Add to dashboard Cite

Conventional magnetic resonance electrical impedance tomography (MREIT) reconstruction methods require administration of two linearly independent currents via at least two electrode pairs. This requires long scanning times and inhibits coordination of MREIT measurements with electrical neuromodulation strategies. We sought to develop an isotropic conductivity reconstruction algorithm in MREIT based on a single current injection, both to decrease scanning time by a factor of two and enable MREIT measurements to be conveniently adapted to general transcranial- or implanted-electrode neurostimulation protocols. In this work, we propose and demonstrate an iterative algorithm that extends previously published MREIT work using two-current administration approaches. The proposed algorithm is a single-current adaptation of the harmonic B z algorithm. Forward modeling of electric potentials is used to capture changes of conductivity along current directions that would normally be invisible using data from a single-current administration. Computational and experimental results show that the reconstruction algorithm is capable of reconstructing isotropic conductivity images that agree well in terms of L 2 error and structural similarity with exact conductivity distributions or two-current-based MREIT reconstructions. We conclude that it is possible to reconstruct high quality electrical conductivity images using MREIT techniques and one current injection only.

show abstract

Accelerating acquisition strategies for low-frequency conductivity imaging using MREIT

Cited by 10 publications

References 35 publications

Low-Frequency Conductivity Tensor Imaging of the Human Head <italic>In Vivo</italic> Using DT-MREIT: First Study

Low-Frequency Conductivity Tensor Imaging of the Human Head <italic>In Vivo</italic> Using DT-MREIT: First Study

Direct detection of neural activity in vitro using magnetic resonance electrical impedance tomography (MREIT)

Low frequency conductivity reconstruction based on a single current injection via MREIT

Contact Info

Product

Resources

About