Hyperpolarized <sup>129</sup>
Xe imaging of the rat lung using spiral IDEAL

Doganay, Ozkan; Wade, Trevor; Hegarty, Elaine; McKenzie, Charles A.; Schulte, Rolf F.; Santyr, Giles

doi:10.1002/mrm.25911

Cited by 26 publications

(38 citation statements)

References 37 publications

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“…Spiral‐IDEAL imaging was used as described previously . The imaging sequence consisted of a single‐shot spiral k‐space trajectory for spatial encoding (2D coronal projection), and four‐point IDEAL for chemical shift encoding.…”

Section: Methodsmentioning

confidence: 99%

“…However, this is challenging due to the small amount of xenon dissolved in the various lung tissues at a given instant (~2%) and the short

T_{2}^{*}

of dissolved 129 Xe (~2 ms at 1.5 T). Recently, a technique has been developed combining rapid spiral readout and iterative decomposition of water and fat with echo asymmetry and least squares estimation (IDEAL) chemical shift encoding to overcome these challenges . Regional differences in gas exchange were demonstrated in rats after hemithoracic irradiation (entire right lung) using this spiral‐IDEAL imaging approach, but these changes were observed entirely between the left and right lungs only .…”

Section: Introductionmentioning

confidence: 99%

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Physiological gas exchange mapping of hyperpolarized ¹²⁹Xe using spiral‐IDEAL and MOXE in a model of regional radiation‐induced lung injury

et al. 2018

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Purpose: To map physiological gas exchange parameters using dissolved hyperpolarized (HP) 129 Xe in a rat model of regional radiation-induced lung injury (RILI) with spiral-IDEAL and the model of xenon exchange (MOXE). Results are compared to quantitative histology of pulmonary tissue and red blood cell (RBC) distribution. Methods: Two cohorts (n = 6 each) of age-matched rats were used. One was irradiated in the rightmedial lung, producing regional injury. Gas exchange was mapped 4 weeks postirradiation by imaging dissolved-phase HP 129 Xe using spiral-IDEAL at five gas exchange timepoints using a clinical 1.5 T scanner. Physiological lung parameters were extracted regionally on a voxel-wise basis using MOXE. Mean gas exchange parameters, specifically air-capillary barrier thickness (d) and hematocrit (HCT) in the right-medial lung were compared to the contralateral lung as well as nonirradiated control animals. Whole-lung spectroscopic analysis of gas exchange was also performed. Results: d was significantly increased (1.43 AE 0.12 lm from 1.07 AE 0.09 lm) and HCT was significantly decreased (17.2 AE 1.2% from 23.6 AE 1.9%) in the right-medial lung (i.e., irradiated region) compared to the contralateral lung of the irradiated rats. These changes were not observed in healthy controls. d and HCT correlated with histologically measured increases in pulmonary tissue heterogeneity (r = 0.77) and decreases in RBC distribution (r = 0.91), respectively. No changes were observed using whole-lung analysis. Conclusion: This work demonstrates the feasibility of mapping gas exchange using HP 129 Xe in an animal model of RILI 4 weeks postirradiation. Spatially resolved gas exchange mapping is sensitive to regional injury between cohorts that was undetected with whole-lung gas exchange analysis, in agreement with histology. Gas exchange mapping holds promise for assessing regional lung function in RILI and other pulmonary diseases.

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Section: Methodsmentioning

confidence: 99%

“…However, this is challenging due to the small amount of xenon dissolved in the various lung tissues at a given instant (~2%) and the short

T_{2}^{*}

Section: Introductionmentioning

confidence: 99%

Physiological gas exchange mapping of hyperpolarized ¹²⁹Xe using spiral‐IDEAL and MOXE in a model of regional radiation‐induced lung injury

et al. 2018

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“…By substituting

{bold-italicC}_{X e}

into Eq. , simulated signal‐time curves were then derived from H1 to H5 for N int = 1, which includes the effects of the number of RF pulses (N = 1:12), flip angle (α = 19°), T 1 = 200 s , and

{normalT}_{2}^{*}

= 25 ms in the phantom. The flip angles,

{normalT}_{2}^{*}

, and T 1 between ROIs were assumed to be constant in Eq.…”

Section: Methodsmentioning

confidence: 99%

“…Where A is a scaling constant that is dependent on 129 Xe polarization levels, coil sensitivity, receive gain, and the point spread function, which depends on the k‐space sampling strategy (i.e., spiral, radial, Cartesian) . T is transmit profile of the RF coil where the flip angle,

α

, changes as a function of the position, r .…”

Section: Theorymentioning

confidence: 99%

“…The relatively long transverse relaxation time (

{normalT}_{2}^{*}

) of 129 Xe in the gas phase (

{normalT}_{2}^{*}

= 52 ± 20 ms at 1.5T) compared to 3 He (

{normalT}_{2}^{*}

= 27.8 ± 1.2 ms at 1.5T) allows the use of longer readout times per interleave, fewer radiofrequency (RF) pulses, and larger flip angles . The use of fewer interleaves allows for rapid coverage of the whole of k‐space, resulting in higher temporal resolution in dynamic gas ventilation imaging.…”

Section: Introductionmentioning

confidence: 99%

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Fast dynamic ventilation MRI of hyperpolarized ¹²⁹Xe using spiral imaging

Doganay

Matin

McIntyre

et al. 2017

Magnetic Resonance in Med

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PurposeTo develop and optimize a rapid dynamic hyperpolarized 129Xe ventilation (DXeV) MRI protocol and investigate the feasibility of capturing pulmonary signal‐time curves in human lungs.Theory and MethodsSpiral k‐space trajectories were designed with the number of interleaves N int = 1, 2, 4, and 8 corresponding to voxel sizes of 8 mm, 5 mm, 4 mm, and 2.5 mm, respectively, for field of view = 15 cm. DXeV images were acquired from a gas‐flow phantom to investigate the ability of N int = 1, 2, 4, and 8 to capture signal‐time curves. A finite element model was constructed to investigate gas‐flow dynamics corroborating the experimental signal‐time curves. DXeV images were also carried out in six subjects (three healthy and three chronic obstructive pulmonary disease subjects).ResultsDXeV images and numerical modelling of signal‐time curves permitted the quantification of temporal and spatial resolutions for different numbers of spiral interleaves. The two‐interleaved spiral (N int = 2) was found to be the most time‐efficient to obtain DXeV images and signal‐time curves of whole lungs with a temporal resolution of 624 ms for 13 slices. Signal‐time curves were well matched in three healthy volunteers. The Spearman's correlations of chronic obstructive pulmonary disease subjects were statistically different from three healthy subjects (P < 0.05).ConclusionThe N int = 2 spiral demonstrates the successful acquisition of DXeV images and signal‐time curves in healthy subjects and chronic obstructive pulmonary disease patients. Magn Reson Med 79:2597–2606, 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.

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Review of Hyperpolarized Pulmonary Functional ¹²⁹Xe MR for Long‐COVID

Wild,

Gleeson,

Svenningsen

et al. 2023

Magnetic Resonance Imaging

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The respiratory consequences of acute COVID‐19 infection and related symptoms tend to resolve 4 weeks post‐infection. However, for some patients, new, recurrent, or persisting symptoms remain beyond the acute phase and persist for months, post‐infection. The symptoms that remain have been referred to as long‐COVID. A number of research sites employed 129Xe magnetic resonance imaging (MRI) during the pandemic and evaluated patients post‐infection, months after hospitalization or home‐based care as a way to better understand the consequences of infection on 129Xe MR gas‐exchange and ventilation imaging. A systematic review and comprehensive search were employed using MEDLINE via PubMed (April 2023) using the National Library of Medicine's Medical Subject Headings and key words: post‐COVID‐19, MRI, 129Xe, long‐COVID, COVID pneumonia, and post‐acute COVID‐19 syndrome. Fifteen peer‐reviewed manuscripts were identified including four editorials, a single letter to the editor, one review article, and nine original research manuscripts (2020–2023). MRI and MR spectroscopy results are summarized from these prospective, controlled studies, which involved small sample sizes ranging from 9 to 76 participants. Key findings included: 1) 129Xe MRI gas‐exchange and ventilation abnormalities, 3 months post‐COVID‐19 infection, and 2) a combination of MRI gas‐exchange and ventilation abnormalities alongside persistent symptoms in patients hospitalized and not hospitalized for COVID‐19, 1‐year post‐infection. The persistence of respiratory symptoms and 129Xe MRI abnormalities in the context of normal or nearly normal pulmonary function test results and chest computed tomography (CT) was consistent. Longitudinal improvements were observed in long‐term follow‐up of long‐COVID patients but mean 129Xe gas‐exchange, ventilation heterogeneity values and symptoms remained abnormal, 1‐year post‐infection. Pulmonary functional MRI using inhaled hyperpolarized 129Xe gas has played a role in detecting gas‐exchange and ventilation abnormalities providing complementary information that may help develop our understanding of the root causes of long‐COVID.Level of Evidence1Technical EfficacyStage 5

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Hyperpolarized ¹²⁹ Xe imaging of the rat lung using spiral IDEAL

Abstract: Single-shot spiral IDEAL imaging of gas, PT and RBC compartments and gas exchange is feasible in rat lung using Hp (129) Xe. Magn Reson Med 76:566-576, 2016. © 2015 Wiley Periodicals, Inc.

Cited by 26 publications

References 37 publications

Physiological gas exchange mapping of hyperpolarized ¹²⁹Xe using spiral‐IDEAL and MOXE in a model of regional radiation‐induced lung injury

Physiological gas exchange mapping of hyperpolarized ¹²⁹Xe using spiral‐IDEAL and MOXE in a model of regional radiation‐induced lung injury

Fast dynamic ventilation MRI of hyperpolarized ¹²⁹Xe using spiral imaging

Review of Hyperpolarized Pulmonary Functional ¹²⁹Xe MR for Long‐COVID

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Hyperpolarized 129 Xe imaging of the rat lung using spiral IDEAL

Abstract: Single-shot spiral IDEAL imaging of gas, PT and RBC compartments and gas exchange is feasible in rat lung using Hp (129) Xe. Magn Reson Med 76:566-576, 2016. © 2015 Wiley Periodicals, Inc.

Cited by 26 publications

References 37 publications

Physiological gas exchange mapping of hyperpolarized 129Xe using spiral‐IDEAL and MOXE in a model of regional radiation‐induced lung injury

Physiological gas exchange mapping of hyperpolarized 129Xe using spiral‐IDEAL and MOXE in a model of regional radiation‐induced lung injury

Fast dynamic ventilation MRI of hyperpolarized 129Xe using spiral imaging

Review of Hyperpolarized Pulmonary Functional 129Xe MR for Long‐COVID

Contact Info

Product

Resources

About

Hyperpolarized ¹²⁹ Xe imaging of the rat lung using spiral IDEAL

Physiological gas exchange mapping of hyperpolarized ¹²⁹Xe using spiral‐IDEAL and MOXE in a model of regional radiation‐induced lung injury

Physiological gas exchange mapping of hyperpolarized ¹²⁹Xe using spiral‐IDEAL and MOXE in a model of regional radiation‐induced lung injury

Fast dynamic ventilation MRI of hyperpolarized ¹²⁹Xe using spiral imaging

Review of Hyperpolarized Pulmonary Functional ¹²⁹Xe MR for Long‐COVID