hyperpolarized-129xe-lung-mri-spectroscopy-mechanically-ventilated

Hyperpolarized <sup>129</sup>Xe Lung MRI and Spectroscopy in Mechanically Ventilated Mice

Hyperpolarized (HP) xenon-129 (129Xe) is an inhaled magnetic resonance imaging (MRI) contrast agent with unique spectral and physical properties that can ...

Cincinnati Children's Hospital Medical Center

Hyperpolarized (HP)  Xe-MRI provides non-invasive methods to quantify lung function and structure, with the  Xe apparent diffusion coefficient (ADC) being a well validated measure of alveolar airspace size. However, the experimental factors that impact the precision and accuracy of HP  Xe ADC measurements have not been rigorously investigated. Here, we introduce an analytical model to predict the experimental uncertainty of  Xe ADC estimates. Additionally, we report ADC dependence on age in healthy pediatric volunteers.

Improving hyperpolarized  Xe ADC mapping in pediatric and adult lungs with uncertainty propagation.

To enable efficient hyperpolarized  Xe diffusion imaging using 2D and 3D (Fermat Looped, ORthogonally Encoded Trajectories, FLORET) spiral sequences and demonstrate that  Xe ADCs obtained using these sequences are comparable to those obtained using a conventional, 2D gradient-recalled echo (GRE) sequence.

Diffusion weighted hyperpolarized  Xe MRI of the lung with 2D and 3D (FLORET) spiral.

Airway clearance therapy (ACT) with a high-frequency chest wall oscillation (HFCWO) vest is a common but time-consuming treatment. Its benefit to quality of life for cystic fibrosis (CF) patients is well established but has been questioned recently as new highly-effective modulator therapies begin to change the treatment landscape. Xe ventilation MRI has been shown to be very sensitive to lung obstruction in mild CF disease, making it an ideal tool to identify and quantify subtle, regional changes.

Short-term structural and functional changes after airway clearance therapy in cystic fibrosis.

To mitigate signal variations caused by inhomogeneous RF and magnetization decay in hyperpolarized  Xe ventilation images using flip-angle maps generated from sequential 2D spiral ventilation images acquired in a breath-hold. Images and correction maps were compared with those obtained using conventional, 2D gradient-recalled echo.

B and magnetization decay correction for hyperpolarized  Xe lung imaging using sequential 2D spiral acquisitions.

MRI assessment and guidance for regionally targeted pulmonary interventions.

Hyperpolarized Xe MRI benefits from non-Cartesian acquisitions that sample k-space efficiently and rapidly. However, their reconstructions are complex and burdened by decay processes unique to hyperpolarized gas. Currently used gridded reconstructions are prone to artifacts caused by magnetization decay and are ill-suited for undersampling. We present a compressed sensing (CS) reconstruction approach that incorporates magnetization decay in the forward model, thereby producing images with increased sharpness and contrast, even in undersampled data.

A decay-modeled compressed sensing reconstruction approach for non-Cartesian hyperpolarized Xe MRI.

Hyperpolarized xenon (Xe) MRI is a noninvasive method to assess pulmonary structure and function. To measure lung microstructure, diffusion-weighted imaging-commonly the apparent diffusion coefficient (ADC)-can be employed to map changes in alveolar-airspace size resulting from normal aging and pulmonary disease. However, low signal-to-noise ratio (SNR) decreases ADC measurement certainty, and biases ADC to spuriously low values. Further, these challenges are most severe in regions of the lung where alveolar simplification or emphysematous remodeling generate abnormally high ADCs. Here, we apply Global Local Higher Order Singular Value Decomposition (GLHOSVD) denoising to enhance image SNR, thereby reducing uncertainty and bias in diffusion measurements.

Improved Diffusion-Weighted Hyperpolarized Xe Lung MRI with Patch-Based Higher-Order, Singular Value Decomposition Denoising.

Cystic Fibrosis (CF) progresses through recurrent infection and inflammation, causing permanent lung function loss and airway remodeling. CT scans reveal abnormally low-density lung parenchyma in CF, but its microstructural nature remains insufficiently explored due to clinical CT limitations. To this end, diffusion-weighted Xe MRI is a non-invasive and validated measure of lung microstructure. In this work, we investigate microstructural changes in people with CF (pwCF) relative to age-matched, healthy subjects using comprehensive imaging and analysis involving pulmonary-function tests (PFTs), and Xe MRI.

Article	Year
Improving hyperpolarized Xe ADC mapping in pediatric and adult lungs with uncertainty propagation. NMR in biomedicine\| PubMed ID: 34729838	2022
Diffusion weighted hyperpolarized Xe MRI of the lung with 2D and 3D (FLORET) spiral. Magnetic resonance in medicine\| PubMed ID: 36352793	2023
Short-term structural and functional changes after airway clearance therapy in cystic fibrosis. Journal of cystic fibrosis : official journal of the European Cystic Fibrosis Society\| PubMed ID: 36740542	2023
B and magnetization decay correction for hyperpolarized Xe lung imaging using sequential 2D spiral acquisitions. Magnetic resonance in medicine\| PubMed ID: 36989185	2023
MRI assessment and guidance for regionally targeted pulmonary interventions. Pediatric pulmonology\| PubMed ID: 37204226	2023
A decay-modeled compressed sensing reconstruction approach for non-Cartesian hyperpolarized Xe MRI. Magnetic resonance in medicine\| PubMed ID: 38860514	2024
Improved Diffusion-Weighted Hyperpolarized Xe Lung MRI with Patch-Based Higher-Order, Singular Value Decomposition Denoising. Academic radiology\| PubMed ID: 38960843	2024
Quantifying abnormal alveolar microstructure in cystic fibrosis lung disease via hyperpolarized Xe diffusion MRI. Journal of cystic fibrosis : official journal of the European Cystic Fibrosis Society\| PubMed ID: 38997823	2024

Abdullah S. Bdaiwi

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