Assessing the feasibility of hyperpolarized 129 Xe multiple‐breath washout MRI in pediatric cystic fibrosis

Autor: Felipe Morgado, Giles E. Santyr, Krzysztof Kowalik, Jonathan H. Rayment, Felix Ratjen, Nikhil Kanhere, Marcus J. Couch
Rok vydání: 2019
Předmět:
Zdroj: Magnetic Resonance in Medicine. 84:304-311
ISSN: 1522-2594
0740-3194
Popis: PURPOSE To assess the feasibility of hyperpolarized 129 Xe multiple-breath washout MRI in pediatric cystic fibrosis (CF) participants with preserved lung function. Fractional ventilation (r), defined as the fractional gas replacement per breath, was mapped using 2 signal models: (1) constant T1 and (2) variable T1 as a function of the hyperpolarized gas washout. METHODS A total of 17 pediatric participants were recruited (mean age 11.7 ± 2.8 years), including 7 children with clinically stable CF and 10 aged-matched healthy controls. Pulmonary function tests were performed, including spirometry, to measure the forced expiratory volume in 1 second and nitrogen multiple-breath washout to measure the lung clearance index. Hyperpolarized 129 Xe MRI was performed during consecutive breaths of air following a single 129 Xe inhalation, and fractional ventilation maps were calculated. RESULTS The forced expiratory volume in 1 second was similar in both groups (P = .32), but there was a statistically significant difference in lung clearance index between healthy and CF participants (P = .001). With variable T1 modeling, CF participants had a mean r of 0.44 ± 0.08 and healthy participants had a mean r of 0.37 ± 0.12 (P = .20). With constant T1 modeling, CF participants had a mean r' of 0.48 ± 0.08, and healthy participants had a mean r' of 0.43 ± 0.12 (P = .32). Therefore, assuming a constant T1 leads to a relative bias in r of 15.1% ± 6.4% and 20.8% ± 7.4% for CF and healthy participants, respectively (P = .12). CONCLUSION This study demonstrates that hyperpolarized 129 Xe multiple-breath washout imaging is feasible in pediatric participants with CF, and inclusion of variable T1 modeling reduces bias in the fractional ventilation measurements.
Databáze: OpenAIRE
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