395 - MRI Phenotyping of BPD: Hyperinflation Phenotype Associated with Poor Respiratory Outcomes in BPD

Publication Number: 1378.395

Chawisa Janjindamai, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States; Laura Bellew, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States; Nara S. Higano, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States; Erik Hysinger, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States; Jason Woods, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States; Paul S. Kingma, Cincinnati Children's Hospital, Cincinnati, OH, United States

Background: Bronchopulmonary dysplasia (BPD) remains the most common chronic respiratory morbidity in preterm infants. Predicting long-term respiratory outcomes is challenging due to heterogeneous lung injury patterns. Our institution developed an MRI parenchymal scoring system that quantifies structural lung abnormalities and correlates with short- and long-term respiratory outcomes. Whole-lung volume normalized to body surface area (WLV/BSA) has also been associated with prolonged respiratory support. Building on these, we identified two MRI-derived phenotypes-hyperinflation (HI) and non-hyperinflation (NHI)-based on parenchymal features and WLV/BSA. The relationship between these phenotypes and respiratory outcomes has not been defined.

Objective: To determine whether infants with an HI phenotype have worse respiratory outcomes compared with those with an NHI phenotype.

Design/Methods: We retrospectively reviewed preterm infants who underwent lung MRI near term-corrected age from 2014-2023. MRIs were scored using the modified Ochiai scoring system, grouped into HI-associated (hyperexpansion, emphysema number, emphysema size) and NHI-associated features (fibrous/interstitial subpleural opacities, bronchovascular distortion, mosaic attenuation). Infants with a total HI-associated score ≥ 1 point higher than a total NHI-associated score OR a WLV/BSA > 600 mL/m² were categorized as HI phenotype; all others were NHI phenotype. Clinical data were collected until discontinuation of respiratory support. Outcomes included duration of respiratory support, length of stay, and tracheostomy rate. Group comparisons were performed using appropriate statistical tests.

Results: Eighty-seven infants were included: 34 (39%) HI and 53 (61%) NHI phenotype. Gestational age, birth weight, SGA prevalence, twin status, sex, race and postmenstrual age at MRI were similar between groups. The HI group had greater WLV/BSA (723 vs 496 mL/m2, p < 0.01) and greater whole-lung density SD (0.18 vs 0.15, p < 0.01). They required longer respiratory support (ventilator 587 vs 59 days; any PPV 587 vs 107 days; any support 712 vs 312 days; all p < 0.01) and required longer hospital stay (250 vs 140 days, p < 0.01). Tracheostomy was more frequent in the HI phenotype (74% vs 28%, p < 0.01). In subgroup analysis, infants with comorbidities were more likely to require > 200 days on a ventilator.

Conclusion(s): MRI-derived HI phenotype correlates with worse outcomes in BPD. Integrating MRI phenotype with comorbidity profiling may enhance risk stratification and guide individualized, earlier, or more aggressive interventions for infants with HI phenotype.

Table 1: Baseline demographic and MRI characteristics of infants with hyperinflation (HI) and non-hyperinflation (NHI) phenotypes.
Values are presented as median (IQR) or n (%). Demographic and clinical variables were similar between groups. The HI group demonstrated significantly greater WLV/BSA, higher hyperinflation scores, lower non-hyperinflation scores, and greater standard deviation of whole-lung density compared with the NHI group. P-values <0.05 were considered significant.

Table 2: Respiratory and clinical outcomes in infants with hyperinflation (HI) and non-hyperinflation (NHI) phenotypes.
Values are presented as median (IQR) or n (%). Compared with the NHI group, the HI group had significantly longer hospital length of stay, prolonged duration of invasive ventilation, longer duration of any positive-pressure ventilation and any respiratory support, and a higher tracheostomy rate. P-values <0.05 indicate statistically significant differences between groups.

Characteristics of infants with hyperinflation (HI) and non-hyperinflation (NHI) phenotypes stratified by duration of ventilator ( <200 vs >200 days).
Values are presented as median (IQR) or n (%). Within both HI and NHI groups, infants requiring >200 days of ventilation demonstrated a significantly higher prevalence of clinical risk factors (history of pulmonary hypertension, airway malacia, SGA, or frequent pneumonia). No significant differences were observed in gestational age, birth weight, sex, race, multiple gestation, or postmenstrual age at MRI across ventilation duration. P-values <0.05 were considered statistically significant.