Respiratory Diseases Unit, Department of Medical and Surgical Sciences, University Hospital of Modena, University of Modena Reggio Emilia, Modena, Italy.
Laboratory of Cell Therapies and Respiratory Medicine, Department of Medical and Surgical Sciences for Children and Adults, University Hospital of Modena, Modena, Italy.
Respir Res. 2024 Oct 5;25(1):359. doi: 10.1186/s12931-024-02970-4.
The usual interstitial pneumonia (UIP) pattern, hallmark of idiopathic pulmonary fibrosis (IPF), may induce harmful local overdistension during mechanical ventilation given the juxtaposition of different tissue elasticities. Mechanotransduction, linking mechanical stress and strain to molecular pro-fibrotic pathways, likely contributes to fibrosis progression. Understanding the mechanical forces and aeration patterns in the lungs of IPF patients is crucial for unraveling potential mechanisms of disease progression. Quantitative lung computed tomography (CT) can accurately assess the air content of lung regions, thus informing on zonal distension. This study aims to investigate radiological evidence of lung over aeration in spontaneously breathing UIP patients compared to healthy controls during maximal inspiration.
Patients with IPF diagnosis referred to the Center for Rare Lung Diseases of the University Hospital of Modena (Italy) in the period 2020-2023 who underwent High Resolution Computed Tomography (HRCT) scans at residual volume (RV) and total lung capacity (TLC) using standardized protocols were retrospectively considered eligible. Patients with no signs of lung disease at HRCT performed with the same image acquisition protocol nor at pulmonary function test (PFTs) served as controls. Lung segmentation and quantitative analysis were performed using 3D Slicer software. Lung volumes were measured, and specific density thresholds defined over aerated and fibrotic regions. Comparison between over aerated lung at RV and TLC in the two groups and according to lung lobes was sought. Further, the correlation between aerated lung and the extent of fibrosis was assessed and compared at RV and TLC.
IPF patients (N = 20) exhibited higher over aerated lung proportions than controls (N = 15) both at RV and TLC (4.5% vs. 0.7%, p < 0.0001 and 13.8% vs. 7%, p < 0.0001 respectively). Over aeration increased significantly from RV to TLC in both groups, with no intergroup difference (p = 0.67). Sensitivity analysis revealed significant variations in over aerated lung areas among lobes when passing from RV to TLC with no difference within lobes (p = 0.28). Correlation between over aeration and fibrosis extent was moderate at RV (r = 0.62, p < 0.0001) and weak at TLC (r = 0.27, p = 0.01), being the two significantly different at interpolation analysis (p < 0.0001).
This study provides the first evidence of radiological signs of lung over aeration in patients with UIP-pattern patients when passing from RV to TLC. These findings offer new insights into the complex interplay between mechanical forces, lung structure, and fibrosis and warrant larger and longitudinal investigations.
特发性肺纤维化（IPF）的典型间质性肺炎（UIP）模式可能导致不同组织弹性的并置导致机械通气期间的有害局部过度膨胀。机械转导将机械应力和应变与分子致纤维化途径联系起来，可能有助于纤维化的进展。了解 IPF 患者肺部的机械力和通气模式对于揭示潜在的疾病进展机制至关重要。定量肺部计算机断层扫描（CT）可以准确评估肺部区域的空气含量，从而提供有关区域膨胀的信息。本研究旨在比较自发性呼吸 UIP 患者与健康对照组在最大吸气时 RV 和 TLC 时的放射学证据，以研究过度通气的证据。
回顾性考虑 2020-2023 年期间在意大利摩德纳大学医院罕见肺部疾病中心就诊并使用标准化方案进行 HRCT 扫描（RV 和 TLC）的 IPF 患者。在相同的图像采集协议下，没有肺部疾病迹象的患者和肺功能测试（PFT）也作为对照组。使用 3D Slicer 软件进行肺分割和定量分析。测量肺容积，并在充气和纤维化区域上定义特定密度阈值。比较两组在 RV 和 TLC 时的过度充气肺以及根据肺叶的比较。进一步评估并比较 RV 和 TLC 时充气肺与纤维化程度的相关性。
与对照组（N = 15）相比，IPF 患者（N = 20）在 RV 和 TLC 时的过度充气肺比例更高（4.5%比 0.7%，p < 0.0001 和 13.8%比 7%，p < 0.0001 分别）。两组的过度充气均从 RV 到 TLC 显著增加，组间无差异（p = 0.67）。敏感性分析显示，从 RV 到 TLC 时，各叶之间过度充气肺面积存在显著差异，但叶内无差异（p = 0.28）。RV 时过度充气与纤维化程度的相关性为中度（r = 0.62，p < 0.0001），TLC 时为弱（r = 0.27，p = 0.01），插值分析差异有统计学意义（p < 0.0001）。
本研究首次提供了 UIP 模式患者从 RV 到 TLC 时肺部过度充气的放射学证据。这些发现为机械力、肺结构和纤维化之间的复杂相互作用提供了新的见解，并需要更大规模和纵向研究。
