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首頁(yè)> 美國(guó)衛(wèi)生研究院文獻(xiàn)>Journal of Aerosol Medicine and Pulmonary Drug Delivery >Measuring Anatomical Distributions of Ventilation and Aerosol Deposition with PET-CT
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Measuring Anatomical Distributions of Ventilation and Aerosol Deposition with PET-CT

機(jī)譯：使用 PET-CT 測(cè)量通氣和氣溶膠沉積的解剖分布

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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.
機(jī)譯：在疾病中，肺功能和結(jié)構(gòu)是異質(zhì)性的，氣溶膠運(yùn)輸和局部沉積在肺各部分之間差異很大。了解這種異質(zhì)性與氣霧劑醫(yī)學(xué)和量化肺不同部位的粘膜纖毛清除率有關(guān)。在本章中，我們描述了正電子發(fā)射斷層掃描 （PET） 成像方法，以定量評(píng)估肺內(nèi)氣溶膠的沉積和通氣分布。來(lái)自計(jì)算機(jī)斷層掃描 （CT） 的解剖信息與 PET 沉積數(shù)據(jù)相結(jié)合，可以估計(jì)支氣管收縮性哮喘受試者的氣道表面濃度和外周組織劑量。制定了一個(gè)理論框架來(lái)量化異質(zhì)通氣、分叉中氣溶膠通氣分布不均勻以及沿氣道樹(shù)路徑從單個(gè)氣道的不同逃逸的影響。該框架應(yīng)用于來(lái)自支氣管收縮性哮喘患者的成像數(shù)據(jù)，以評(píng)估這些因素對(duì)肺葉沉積不均勻性的貢獻(xiàn)。該分析的結(jié)果表明，通氣的異質(zhì)性平均導(dǎo)致了超過(guò)三分之一的肺葉間沉積變異性。個(gè)體肺通氣的實(shí)際貢獻(xiàn)是可變的，取決于受試者在氣霧劑吸入期間使用的呼吸頻率;最大的貢獻(xiàn)是患者呼吸緩慢。在呼吸加快的受試者中，通氣的貢獻(xiàn)降低，在這些受試者中，更多擴(kuò)張的肺葉比擴(kuò)張較少的肺葉顯示出更低的單位通氣沉積。從兩次靜態(tài) CT 掃描（通常用作通氣的替代指標(biāo)）測(cè)量的肺葉擴(kuò)張變化與氣溶膠沉積或 PET 測(cè)量的通氣無(wú)關(guān)。這表明需要?jiǎng)討B(tài)信息來(lái)為哮喘受試者提供適當(dāng)?shù)耐夤烙?jì)。我們希望使用此處介紹的工具加強(qiáng)對(duì)氣道和組織劑量異質(zhì)性原因的理解，將有助于優(yōu)化吸入療法的治療效果，同時(shí)最大限度地減少毒性。

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