Synchronous acquisition of hyperpolarised <sup>3</sup>He and <sup>1</sup>H MR images of the lungs – maximising mutual anatomical and functional information

Wild, Jim M.; Ajraoui, Salma; Deppe, Martin H.; Parnell, Steven R.; Marshall, Helen; Parra‐Robles, Juan; Ireland, R.H.

doi:10.1002/nbm.1565

Cited by 46 publications

(62 citation statements)

References 35 publications

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“…We have since found it beneficial to collect breath-hold anatomical images after subjects inhale air from a 1-liter bag rather than a self-directed breath-hold. Alternatively, there may be benefit to simultaneously acquiring the 1 H thoracic cavity image and the HP gas ventilation image within a single breath-hold, as described by Wild et al(39). Such an approach should largely obviate the need for registration, or at least greatly reduce the degree of image warping required.…”

Section: Discussionmentioning

confidence: 99%

Dose and pulse sequence considerations for hyperpolarized 129Xe ventilation MRI

Robertson

Kaushik

et al. 2015

Magnetic Resonance Imaging

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Purpose The aim of this study was to evaluate the effect of hyperpolarized 129Xe dose on image signal-to-noise ratio (SNR) and ventilation defect conspicuity on both multi-slice gradient echo and isotropic 3D-radially acquired ventilation MRI. Materials and Methods Ten non-smoking older subjects (ages 60.8 ± 7.9 years) underwent hyperpolarized (HP) 129Xe ventilation MRI using both GRE and 3D-radial acquisitions, each tested using a 71 ml (high) and 24 ml (low) dose equivalent (DE) of fully polarized, fully enriched 129Xe. For all images SNR and ventilation defect percentage (VDP) was calculated. Results Normalized SNR (SNRn), obtained by dividing SNR by voxel volume and dose was higher for high-DE GRE acquisitions (SNRn=1.9±0.8 ml-2) than low-DE GRE scans (SNRn=0.8±0.2 ml-2). Radially acquired images exhibited a more consistent, albeit lower SNRn (High-DE: SNRn=0.5±0.1 ml-2, low-DE: SNRn=0.5±0.2 ml-2). VDP was indistinguishable across all scans. Conclusions These results suggest images acquired using the high-DE GRE sequence provided the highest SNRn, which was in agreement with previous reports in the literature. 3D-radial images had lower SNRn, but have advantages for visual display, monitoring magnetization dynamics, and visualizing physiological gradients. By evaluating normalized SNR in the context of dose-equivalent formalism, it should be possible to predict 129Xe dose requirements and quantify the benefits of more efficient transmit/receive coils, field strengths, and pulse sequences.

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Section: Discussionmentioning

confidence: 99%

Dose and pulse sequence considerations for hyperpolarized 129Xe ventilation MRI

Robertson

Kaushik

et al. 2015

Magnetic Resonance Imaging

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“…First, since the thoracic cavity and ventilation images were obtained during different breath-holds, body movement, and lung volume differences could create difficulties in registering the two images. Thus, there may be benefit in simultaneously acquiring the 1 H thoracic cavity image and the HP gas ventilation image within a single breath-hold, as described by Wild et al (21). Such an approach should largely obviate the need for registration, or at least greatly reduce the degree of image warping required.…”

Section: Discussionmentioning

confidence: 99%

Extending Semiautomatic Ventilation Defect Analysis for Hyperpolarized 129Xe Ventilation MRI

He¹,

Kaushik²,

Robertson³

et al. 2014

Academic Radiology

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Rationale and Objectives Clinical deployment of hyperpolarized (HP) 129Xe MRI requires accurate quantification and visualization of the ventilation defect percentage (VDP). Here, we improve the robustness of our previous semi-automated analysis method to reduce operator dependence, correct for B1 inhomogeneity and vascular structures, and extend the analysis to display multiple intensity clusters. Materials and Methods Two segmentation methods were compared—seeded region-growing, previously validated by expert reader scoring, and a new linear-binning method that corrects for the effects of bias field and vascular structures. The new method removes nearly all operator intervention by re-scaling the 129Xe MRI to the 99th percentile of the cumulative distribution and applying fixed thresholds to classify 129Xe voxels into 4 clusters: defect, low, medium, and high intensity. The methods were applied to 24 subjects including chronic obstructive pulmonary disease (COPD) subjects (n = 8), age-matched controls (n = 8), and healthy normal subjects (n = 8). Results Linear-binning enabled a faster and more reproducible workflow, and enabled analysis of an additional 0.25 ± 0.18 L of lung volume by accounting for vasculature. Like region-growing, linear-binning VDP correlated strongly with reader scoring (R2 = 0.93, p<0.0001), but with less systematic bias. Moreover, linear-binning maps clearly depict regions of low and high intensity that may prove useful for phenotyping subjects with COPD. Conclusions Corrected linear-binning provides a robust means to quantify 129Xe ventilation images, yielding VDP values that are indistinguishable from expert reader scores, while exploiting the entire dynamic range to depict multiple image clusters.

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“…The method of automatic registration assumes intrinsic spatial registration of gas MRI and 1 H MRI, preferably due to same breath-hold acquisition (Wild et al, 2011), although the method is still potentially viable if hyperpolarized gas and 1 H MR image registration is required from separate breath-holds ).…”

Section: Discussionmentioning

confidence: 99%

“…Computational times for the full diffeomorphic pipeline ranged from 28 to 37 minutes, including the rigid pre-alignment and affine stages. He MRI were acquired in the same breath hold and spatially coregistered (Wild et al, 2011), the same transform to map 1 H MRI to CT was applied to map 3 He MRI to CT with linear interpolation for the indirect registrations using the antsApplyTransform tool available in ANTs.…”

Section: Image Registrationmentioning

confidence: 99%

A method for quantitative analysis of regional lung ventilation using deformable image registration of CT and hybrid hyperpolarized gas/¹H MRI

et al. 2014

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This is a repository copy of ReuseUnless indicated otherwise, fulltext items are protected by copyright with all rights reserved. The copyright exception in section 29 of the Copyright, Designs and Patents Act 1988 allows the making of a single copy solely for the purpose of non-commercial research or private study within the limits of fair dealing. The publisher or other rights-holder may allow further reproduction and re-use of this version -refer to the White Rose Research Online record for this item. Where records identify the publisher as the copyright holder, users can verify any specific terms of use on the publisher's website. TakedownIf you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing eprints@whiterose.ac.uk including the URL of the record and the reason for the withdrawal request.A method for quantitative analysis of regional lung ventilation using deformable image registration of CT and hybrid Short Title Hyperpolarised gas MRI and CT image registration AbstractHyperpolarized gas MRI generates highly detailed maps of lung ventilation and physiological function while CT provides corresponding anatomical and structural information. Fusion of such complementary images enables quantitative analysis of pulmonary structure-function. However, direct image registration of hyperpolarized gas MRI to CT is problematic, particularly in lungs whose boundaries are difficult to delineate due to ventilation heterogeneity. This study presents a novel indirect method of registering hyperpolarized gas MRI to CT utilizing 1 H-structural MR images that are acquired in the same breath-hold as the gas MRI. The feasibility of using this technique for regional quantification of ventilation of specific pulmonary structures is demonstrated for the lobes.The direct and indirect methods of hyperpolarized gas MRI to CT image registration were compared using lung images from 15 asthma patients. Both affine and diffeomorphic image transformations were implemented. Registration accuracy was evaluated using the target registration error (TRE) of anatomical landmarks identified on 1 H MRI and CT. Wilcoxon signed-rank test was used to test statistical significance.For the affine transformation, the indirect method of image registration was significantly more accurate than the direct method (TRE=14.7±3.2 vs. 19.6±12.7mm, p=0.036). Using a deformable transformation, the indirect method was also more accurate than the direct method (TRE=13.5±3.3 vs. 20.4±12.8mm, p=0.006).Accurate image registration is critical for quantification of regional lung ventilation with hyperpolarized gas MRI within the anatomy delineated by CT. Automatic deformable image registration of hyperpolarized gas MRI to CT via same breath-hold 1 H MRI is more accurate than direct registration. Potential applications include improved multi-modality image fusion, functionally-weighted radiotherapy planning, and quantification of lobar ventilation in obstructive airways disease.

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Synchronous acquisition of hyperpolarised ³He and ¹H MR images of the lungs – maximising mutual anatomical and functional information

Cited by 46 publications

References 35 publications

Dose and pulse sequence considerations for hyperpolarized 129Xe ventilation MRI

Dose and pulse sequence considerations for hyperpolarized 129Xe ventilation MRI

Extending Semiautomatic Ventilation Defect Analysis for Hyperpolarized 129Xe Ventilation MRI

A method for quantitative analysis of regional lung ventilation using deformable image registration of CT and hybrid hyperpolarized gas/¹H MRI

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Synchronous acquisition of hyperpolarised 3He and 1H MR images of the lungs – maximising mutual anatomical and functional information

Cited by 46 publications

References 35 publications

Dose and pulse sequence considerations for hyperpolarized 129Xe ventilation MRI

Dose and pulse sequence considerations for hyperpolarized 129Xe ventilation MRI

Extending Semiautomatic Ventilation Defect Analysis for Hyperpolarized 129Xe Ventilation MRI

A method for quantitative analysis of regional lung ventilation using deformable image registration of CT and hybrid hyperpolarized gas/1H MRI

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Synchronous acquisition of hyperpolarised ³He and ¹H MR images of the lungs – maximising mutual anatomical and functional information

A method for quantitative analysis of regional lung ventilation using deformable image registration of CT and hybrid hyperpolarized gas/¹H MRI