Xenon imaging could detect lung involvement after HSCT

SALT LAKE CITY – Hyperpolarized xenon-129 magnetic resonance imaging, or ¹²⁹Xe MRI, showed strong promise for revealing early lung ventilation deficits in pediatric hematopoietic stem cell transplant (HSCT) patients in a proof-of-concept study.

The use of hyperpolarized xenon gas in this setting remains investigational, but is emerging as a safe non-ionizing approach for mapping and quantifying regional airway obstruction in the pediatric population. It has been shown to be more sensitive to early disease than the current clinical gold standard of measuring forced expiratory volume in 1 second (FEV₁) by spirometry, Laura L. Walkup, PhD, said at the combined annual meetings of the Center for International Blood & Marrow Transplant Research and the American Society for Blood and Marrow Transplantation.

The ¹²⁹Xe MRI provides regional information that spirometry cannot, allowing for a targeted approach to planned procedures such as bronchoscopy, said Dr. Walkup of Cincinnati Children’s Hospital Medical Center.

“We hypothesized that hyperpolarized ¹²⁹Xe MRI would be sensitive to lung abnormalities in the pediatric HSCT population,” she said.

Of 13 patients aged 6-13 years (mean, 10 years) who were enrolled in the study and underwent ¹²⁹XeMRI, 9 also completed spirometry successfully, and the average FEV₁ in those patients was 83% of the predicted value.

Ventilation deficits were apparent on the ¹²⁹Xe MRI imaging in 8 of the 13 subjects and varied in regional distribution. The whole-lung ¹²⁹Xe ventilation defect percentage for the HSCT group was 14%, which was significantly greater than the approximately 6% ventilation defect percentage in a cohort of age-matched controls, Dr. Walkup said, noting that ventilation deficits were seen in three of four subjects who were unable to complete reliable spirometry.

“So those are lung abnormalities that may have otherwise gone undetected,” she said, adding that hyperpolarized xenon gas also highlighted the wide individual variation in ventilation, even among cases with similar FEV₁ percentages.