Hahn, Lewis D.

Pulmonary developmental disorders comprise a heterogeneous group of congenital abnormalities involving the airways, lung parenchyma, pulmonary vasculature, or overlapping developmental pathways. Although these conditions commonly present during infancy or childhood, many remain clinically silent until adulthood, when they are discovered incidentally or manifest with recurrent respiratory symptoms such as infection, hemoptysis, or progressive dyspnea. These abnormalities may be broadly categorized into airway, vascular, parenchymal, and mixed developmental anomalies. Airway abnormalities include congenital tracheobronchomegaly, branching anomalies of the tracheobronchial tree, bronchial atresia, bronchogenic cysts, congenital pulmonary airway malformations (CPAM), and bronchopulmonary sequestration (BPS). Vascular anomalies include pulmonary artery sling, proximal interruption of the pulmonary artery, Scimitar syndrome, and meandering pulmonary veins. Parenchymal disorders encompass congenital lobar overinflation and pulmonary hypoplasia. Increasing recognition of overlapping lesions, particularly combinations of CPAM, sequestration, and bronchial atresia, has challenged traditional compartmental classification systems and supports a developmental spectrum model. This review synthesizes contemporary concepts regarding embryologic mechanisms, pathogenesis, imaging findings, and management of these entities in adults. Particular emphasis is placed on imaging evaluation with CT and MRI, updated terminology, evolving molecular understanding of CPAMs, including lesions with malignant potential, and distinctions between congenital sequestration and pseudosequestration. Recognition of these disorders and their associated anomalies is essential for accurate diagnosis, appropriate management, and surgical planning in adult patients.

Abstract Rationale Portopulmonary hypertension (POPH) and hepatopulmonary syndrome (HPS) are two distinct pulmonary vascular complications of liver disease. POPH is characterized by pulmonary hypertension and elevated pulmonary vascular resistance while HPS is characterized by intrapulmonary vasodilation and hypoxemia. POPH and HPS reflect opposing pulmonary vascular responses with markedly different therapeutic and transplant implications. Accurate distinction on imaging may aid clinical decision-making and risk stratification. We aimed to quantitatively characterize and compare chest CT imaging features of POPH and HPS compared to controls with isolated portal hypertension (PoH). Methods Three cohorts of HPS, POPH, and PoH were included (n = 5 per cohort). POPH patients with intrapulmonary vasodilation on contrast echocardiography were excluded. Contrast-enhanced chest CTs with slice thickness ≤ 1.5mm obtained closest to the time of diagnosis were selected (mean 2.7 years following diagnosis). CT images were analyzed using a deep learning algorithm developed in-house that segmented and computed volumes of central, interlobar, peripheral, upper peripheral, and lower peripheral pulmonary arteries (PAs); total, upper, and lower pulmonary veins (PVs); and the four cardiac chambers. Resulting volumes were indexed by body-surface area. One-way analysis of variance (ANOVA) was performed with a post-hoc pairwise Mann-Whitney U test for comparison. Results Patients with HPS were 80% male, had a mean age of 48.6±17.4, and mean MELD-Na of 15.4±3.4. The POPH cohort was 20% male, had a mean age of 56.8±11.9, and mean MELD-Na of 13.4±4.0. The PoH cohort was 100% male, had a mean age of 62.8±4.8, and mean MELD-Na of 12.8±8.8. HPS patients had smaller central PA volumes (mean 26.4±1.8 mm2/m2) compared to both PoH (mean 38.6±9.8 mm2/m2, p = 0.03) and POPH patients (44.8±10.8 mm2/m2, p = 0.008). HPS patients, however, had larger lower peripheral PA (mean 30.7±1.9 mm2/m2) and PV (mean 28.3±6.7 mm2/m2) volumes compared to PoH (PAs mean 20.1±4.8 mm2/m2, p = 0.008; PVs mean 18.2±2.8 mm2/m2, p = 0.02) and larger lower peripheral PA volumes compared to POPH patients (PAs mean 22.1±5.1 mm2/m2, p = 0.03). There was no significant difference in volumes between POPH and PoH for all segments. Conclusion Compared to PoH and POPH, HPS is associated with lower central PA volume and higher peripheral PA volume in the lower lungs. Volumes were similar between POPH and PoH; however, this may reflect limited statistical power given the small sample size. Larger studies are needed to further delineate imaging distinctions between POPH, HPS, and PoH. This abstract is funded by: NHLBI

Abstract Rationale Mucus plugs occur in chronic obstructive pulmonary disease (COPD), but little is known about their size and airway location or whether these mucus plug features change as emphysema worsens. Methods Computed tomographic lung scans from 31 participants with COPD from the SubPopulations and InteRmediate Outcomes In COPD Study (SPIROMICS) cohort were analyzed to quantify mucus plug size and airway location and extent of emphysema. Radiologist annotations of mucus plugs were incorporated in an image processing pipeline to generate size and location information. Emphysema was quantified as the percentage of voxels less than -950 Hounsfield units. Measurements and Main Results The length distribution of 563 annotated mucus plugs varied from 2 to 50 mm. The distribution was multimodal, and an 11-mm length defined short (“stubby,” ≤11 mm) and long (“stringy,” >11 mm) plug phenotypes, with stubby plugs being most common (64%). Mucus plugs localized predominantly to airway generations 6 to 9, and their prevalence was highest in lower lobes. On a lobar basis, the mucus plug number decreased as emphysema percentage increased, whereas average mucus plug volume tended to increase. Conclusion COPD is characterized by mucus plugs of varying size and shape, and emphysematous lung regions may be differentially susceptible to formation of these plugs. The location of mucus plugs in segmental and subsegmental airways in COPD makes them amenable to treatment with inhaled medications or bronchoscopy.