Elevated lung volumes in neonates with bronchopulmonary dysplasia measured via MRI

Abstract

Background Bronchopulmonary dysplasia (BPD) is a chronic lung disease of prematurity defined by requirement for respiratory support at 36 weeks postmenstrual age (PMA), but structural sequelae like lung hyperinflation are often not quantified. Quiet‐breathing, nonsedated magnetic resonance imaging (MRI) allows tomographic quantification of lung volumes and densities. We hypothesized that functional residual capacity (FRC) and intrapleural volume (IV) are increased in BPD and correlate with qualitative radiological scoring of hyperinflation. Methods Ultrashort echo time (UTE) MRI of 17 neonates (acquired at ~39 weeks PMA) were reconstructed at end‐expiration and end‐inspiration via the time course of the k0 point in k‐space. Images were segmented to determine total lung, tidal, parenchymal tissue, and vascular tissue volumes. FRC was calculated by subtracting parenchymal and vascular tissue volumes from IV. Respiratory rate (RR) was calculated via the UTE respiratory waveform, yielding estimates of minute ventilation when combined with tidal volumes (TVs). Two radiologists scored hyperinflation on the MR images. Results IV at FRC increased in BPD: for control, mild, and severe (patients the median volumes were 32.8, 33.5, and 50.9 mL/kg, respectively. TV (medians: 2.21, 3.64, and 4.84 mL/kg) and minute ventilation (medians: 493, 750, and 991 mL/min) increased with increasing severity of BPD (despite decreasing RR, medians: 75.6, 63.0, and 56.1 breaths/min). FRC increased with increasing severity of BPD (39.3, 38.3, and 56.0 mL, respectively). Findings were consistent with increased hyperinflation scored by radiologists. Conclusions This study demonstrates that UTE MRI can quantify hyperinflation in neonatal BPD and that lung volumes significantly increase with disease severity.

Subglottic Stenosis Position Affects Work of Breathing

“…The shape of the respiratory waveform was obtained from raw respiration-modulated MRI data (the center of k-space). 18,26,27 These airflow rates were applied at the left and right bronchus. Peak flow rates for each lung are given in Table I.…”

Characterization of and tissue density in the human lung: Application to neonatal imaging in the intensive care unit

“…The original 3D ultrashort echo time (UTE) technique, applied by our group in the NICU setting, has been further developed to allow self‐navigated retrospective respiratory gating to reduce motion‐related blurring and reconstruction of images at multiple respiratory phases. Furthermore, it has been demonstrated to provide quantitative parenchymal lung density measures that correlate well with CT, quantify lung volumes and hyperinflation, and predict short‐term clinical outcomes in NICU patients with bronchopulmonary dysplasia (BPD) . In this work, we apply the self‐navigated UTE MRI technique to acquire data at multiple echo times (TEs), allowing quantitative mapping of and the associated corrected spin density.…”

The current status and further prospects for lung magnetic resonance imaging in pediatric radiology

“…In addition, lung MRI offers the possibility of functional assessment regarding ventilation and perfusion [2], which can only be achieved with functional diagnostics or nuclear medical methods at this point. Functional lung MRI does not yet play a role in clinical routine [3,4]. The exclusively morphological evaluation of the lung with conventional MR proton imaging has become the method of first choice at many pediatric radiology facilities when sectional imaging of the lung is necessary [5,6].…”