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

University of Cincinnati

There is no agreed upon method for quantifying ventilation defect percentage (VDP) with high sensitivity and specificity from hyperpolarized (HP) gas ventilation MR images in multiple pulmonary diseases for both pediatrics and adults, yet identifying such methods will be necessary for future multi-site trials. Most HP gas MRI ventilation research focuses on a specific pulmonary disease and utilizes one quantification scheme for determining VDP. Here we sought to determine the potential of different methods for quantifying VDP from HP Xe images in multiple pulmonary diseases through comparison of the most utilized quantification schemes: linear binning and thresholding.

Hyperpolarized Xenon MRI Ventilation Defect Quantification via Thresholding and Linear Binning in Multiple Pulmonary Diseases.

Xenon-129 ( Xe) gas-exchange MRI is a pulmonary-imaging technique that provides quantitative metrics for lung structure and function and is often compared to pulmonary-function tests. Unlike such tests, it does not normalize to predictive values based on demographic variables such as age. Many sites have alluded to an age dependence in gas-exchange metrics; however, a procedure for normalizing metrics has not yet been introduced.

Childhood to adulthood: Accounting for age dependence in healthy-reference distributions in  Xe gas-exchange MRI.

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.

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.

MRI with xenon-129 gas (Xe MRI) can assess airflow obstruction and heterogeneity in lung diseases. Specifically, Xe MRI may represent a sensitive modality for future therapeutic trials of cystic fibrosis (CF) therapies. The reproducibility of Xe MRI has not yet been assessed in the context of a multi-site study.

Joseph W. Plummer

Center for Pulmonary Imaging Research,
Division of Pulmonary Medicine,
Center for Pulmonary Imaging Research, Division of Pulmonary Medicine

Cincinnati Children's Hospital Medical Center

Hyperpolarized ¹²⁹Xe Lung MRI and Spectroscopy in Mechanically Ventilated Mice

Joseph W. Plummer

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Cincinnati Children's Hospital Medical Center

Hyperpolarized 129Xe Lung MRI and Spectroscopy in Mechanically Ventilated Mice

Center for Pulmonary Imaging Research,
Division of Pulmonary Medicine,
Center for Pulmonary Imaging Research, Division of Pulmonary Medicine

Hyperpolarized ¹²⁹Xe Lung MRI and Spectroscopy in Mechanically Ventilated Mice