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129Xe MRI detects ventilation deficits in pediatric stem-cell transplant patients unable to perform spirometry.

Research paper by Laura L LL Walkup, Kasiani K Myers, Javier J El-Bietar, Adam A Nelson, Matthew M MM Willmering, Michael M Grimley, Stella M SM Davies, Christopher C Towe, Jason C JC Woods

Indexed on: 10 Mar '19Published on: 09 Mar '19Published in: European Respiratory Journal



Abstract

Early detection of pulmonary morbidity following hematopoietic stem cell transplantation (HSCT) remains an important challenge for intervention, primarily due to the insensitivity of spirometry to early change, and in pediatrics, patient compliance provides additional challenges. Regional lung ventilation abnormalities in pediatric HSCT patients were quantified using hyperpolarized Xe magnetic resonance imaging (MRI) and compared to spirometry. Medically-stable, pediatric allogeneic HSCT patients (n=23, ages 6-16) underwent an outpatient MRI where regional ventilation was quantified with a breath-hold of hyperpolarized Xe gas. Ventilation deficits, regions of the lung that poorly ventilate due to obstruction, were quantified as a ventilation defect percentage (VDP) and compared to FEV, FEV/FVC ratio, and FEF from spirometry using linear regression. The mean Xe VDP was 10.5%±9.4% (range 2.6-41.4%). Xe VDP correlated with FEV, FEV/FVC ratio, and FEF (p≤0.02 for all comparisons). Ventilation deficits were detected in patients with normal spirometry (, FEV>80%), supporting the sensitivity of Xe MRI to early obstruction reported in other pulmonary conditions. Seven patients (30%) could not perform spirometry, yet ventilation deficits were observed in 5 of these patients, detecting abnormalities that otherwise may have gone undetected and untreated until advanced. Lung ventilation deficits were detected using hyperpolarized Xe gas MRI in asymptomatic pediatric HSCT patients and in a subgroup who were unable to perform reliable spirometry. Xe MRI provides a reliable imaging-based assessment of pulmonary involvement in this potentially difficult-to-diagnose pediatric population. Copyright ©ERS 2019.