A two-center analysis of hyperpolarized 129Xe lung MRI in stable pediatric cystic fibrosis: Potential as a biomarker for multi-site trials

Abstract

Background: The ventilation defect percent (VDP), measured from hyperpolarized (HP) 129 Xe magnetic resonance imaging (MRI), is sensitive to functional changes in cystic fibrosis (CF) lung disease. The purpose of this study was to measure and compare VDP from HP 129 Xe MRI acquired at two institutions in stable pediatric CF subjects with preserved lung function. Methods: This retrospective analysis included 26 participants from two institutions (18 CF, 8 healthy, age range 10-17). Pulmonary function tests, N 2 multiple breath washout (to measure lung clearance index, LCI), and HP 129 Xe MRI were performed. VDP measurements were compared between two trained analysts using meananchored linear binning. Correlations were investigated for VDP compared to the forced expiratory volume in one second (FEV 1 ) and LCI. Results: VDP measurements agreed for the two analysts with an intraclass correlation coefficient of 0.99. In the combined dataset, VDP measured by Analyst 1 was 5.96 ± 1.82% and 15.96 ± 6.76% for the healthy and CF groups, respectively (p = .0004). Analyst 2 showed similar differences between healthy and CF (p = .0003). VDP measured by either analyst was shown to correlate with FEV 1 (R 2 = 0.33, p = .003; and R 2 = 0.26, p = .009 for Analysts 1 and 2, respectively) and LCI (R 2 = 0.76, p b .0001; and R 2 = 0.77, p b .0001 for Analysts 1 and 2, respectively). Conclusion: HP 129 Xe MRI provides a robust measurement of ventilation heterogeneity in stable pediatric CF subjects at two sites. Since measurements performed at two sites yielded similar VDP values with near-identical values between different analysts, implementation of the technique in multi-center trials in CF appears feasible.

Improved pulmonary 129Xe ventilation imaging via 3D‐spiral UTE MRI

“…Hyperpolarized 129 Xe ventilation imaging quantifies regional ventilation and is sensitive to airway obstruction in a wide variety of diseases . The technique is safe and well‐tolerated for many populations, including pediatrics .…”

“…A standard approach to ventilation imaging incorporates 2D gradient‐recalled echo (2D‐GRE) sequences limited to a single breath‐hold (<16 seconds). Due to the breath‐hold and gradient limitations, the lung is typically acquired with thick slices (~10‐15 mm), which may suffer from imperfect slice selection . Additionally, each slice is acquired at different times during the breath‐hold, causing undesired T 1 weighting in later slices.…”

“…Hyperpolarized 129 Xe ventilation imaging quantifies regional ventilation and is sensitive to airway obstruction in a wide variety of diseases. [1][2][3][4][5][6][7][8][9][10][11][12] The technique is safe and well-tolerated for many populations, including pediatrics. 1,13,14 Ventilation imaging relies on obtaining reliable, spin density-weighted images to quantify xenon regionally in the lung.…”

“…Due to the breath-hold and gradient limitations, the lung is typically acquired with thick slices (~10-15 mm), which may suffer from imperfect slice selection. 3 Additionally, each slice is acquired at different times during the breath-hold, causing undesired T 1 weighting in later slices. These limitations suggest that HP 129 Xe imaging using true 3D acquisitions could yield superior performance and quantitative accuracy.…”

Chemical shift of 129Xe dissolved in red blood cells: Application to a rat model of bronchopulmonary dysplasia

“…In turn, this may inform interventional practices or treatments. Furthermore, δ RBC may provide useful information about the consequences of other pulmonary diseases, including cystic fibrosis, asthma, and chronic obstructive lung disease . δ RBC can also be measured in distal organs such as the brain of both rats and humans and, therefore, has the potential for in vivo evaluation of oxygenation in a wider range of applications.…”