Measuring Anatomical Distributions of Ventilation and Aerosol Deposition with PET-CT.
Measuring Anatomical Distributions of Ventilation and Aerosol Deposition with PET-CT.
复制标题
使用 PET-CT 测量通风和气溶胶沉积的解剖分布。
DOI：
10.1089/jamp.2023.29086.jgv
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发表时间：
2023
影响因子：
3.4
通讯作者：
Venegas,JoseG
中科院分区：
文献类型：
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作者：
Venegas,JoseG
在疾病中，肺功能和结构是异质的，并且气溶胶输送和局部沉积在肺的各个部分之间存在显着差异。了解这种异质性与气雾剂医学以及量化肺部不同部位的粘膜纤毛清除率相关。在本章中，我们描述了用于定量评估肺内气溶胶沉积和通气分布的正电子发射断层扫描（PET）成像方法。计算机断层扫描 (CT) 的解剖信息与 PET 沉积数据相结合，可以估计支气管收缩的哮喘受试者的气道表面浓度和外周组织剂量。制定了一个理论框架来量化非均质通气、分叉处气溶胶通气分布不均匀以及沿气道树路径从各个气道逸出的变化的影响。该框架应用于支气管收缩哮喘患者的成像数据，以评估这些因素对肺叶沉积不均匀性的影响。该分析结果表明，通气的异质性平均影响了叶间沉积变异性的三分之一以上。个体肺部通气的实际贡献是可变的，并且取决于受试者在气雾吸入期间使用的呼吸频率；贡献最大的是呼吸缓慢的患者。在呼吸较快的受试者中，通气的贡献减少，与这些受试者中扩张较少的肺叶相比，扩张较多的肺叶显示出单位通气量沉积量较低。通过两次静态 CT 扫描测量的肺叶扩张变化（通常用作通气的替代指标）与气溶胶沉积或 PET 测量的通气量无关。这表明需要动态信息来为哮喘受试者提供正确的通气估计。我们希望使用此处介绍的工具加深对气道和组织剂量异质性原因的理解，将有助于优化吸入疗法的治疗效果，同时最大限度地减少毒性。
In disease, lung function and structure are heterogeneous, and aerosol transport and local deposition vary significantly among parts of the lung. Understanding such heterogeneity is relevant to aerosol medicine and for quantifying mucociliary clearance from different parts of the lung. In this chapter, we describe positron emission tomography (PET) imaging methods to quantitatively assess the deposition of aerosol and ventilation distribution within the lung. The anatomical information from computed tomography (CT) combined with the PET-deposition data allows estimates of airway surface concentration and peripheral tissue dosing in bronchoconstricted asthmatic subjects. A theoretical framework is formulated to quantify the effects of heterogeneous ventilation, uneven aerosol ventilation distribution in bifurcations, and varying escape from individual airways along a path of the airway tree. The framework is applied to imaging data from bronchoconstricted asthmatics to assess the contributions of these factors to the unevenness in lobar deposition. Results from this analysis show that the heterogeneity of ventilation contributes on average to more than one-third of the variability in interlobar deposition. Actual contribution of ventilation in individual lungs was variable and dependent on the breathing rate used by the subject during aerosol inhalation; the highest contribution was in patients breathing slowly. In subjects breathing faster, contribution of ventilation was reduced, with more expanded lobes showing lower deposition per unit ventilation than less expanded ones in these subjects. The lobar change in expansion measured from two static CT scans, which is commonly used as a surrogate for ventilation, did not correlate with aerosol deposition or with PET-measured ventilation. This suggests that dynamic information is needed to provide proper estimates of ventilation for asthmatic subjects. We hope that the enhanced understanding of the causes of heterogeneity in airway and tissue dosing using the tools presented here will help to optimize therapeutic effectiveness of inhalation therapy while minimizing toxicity.