Human air space shapes, sizes, areas, and volumes

Hansen, J. E.; Ampaya, E. P.

doi:10.1152/jappl.1975.38.6.990

Cited by 185 publications

(87 citation statements)

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“…Areas under these points (alveolar or duct spaces) were classified as normal (N), centrilobular (CLE) or panacinar (PLE) spaces. In normal lung, the diameter of alveoli around the acinus constitutes about a quarter to a third of the outer diameter of the alveolar duct [13]. In PLE, the distinction between alveoli and alveolar ducts tends to become lost as alveoli lose their sharp angles, enlarge and then lose their contrast in size and shape with alveolar ducts.…”

Section: Emphysema Point Countingmentioning

confidence: 99%

Extent of centrilobular and panacinar emphysema in smokers' lungs: pathological and mechanical implications

Saetta¹,

Kim²,

Izquierdo³

et al. 1994

Eur Respir J

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E Ex xt te en nt t o of f cce en nt tr ri il lo ob bu ul la ar r a an nd d p pa an na ac ci in na ar r e em mp ph hy ys se em ma a i in n s sm mo ok ke er rs s' ' l lu un ng gs s: : p pa at th ho ol lo og gi ic ca al l a an nd d m me ec ch ha an ni ic ca al l i im mp pl li ic ca at ti io on ns s ABSTRACT: In order to quantify the extent of centrilobular (CLE) and panacinar (PLE) emphysema and the degree of the possible overlap between the two forms in smokers, the lungs of 25 smokers undergoing lung resection for peripheral lung tumours were studied. The extent of CLE and PLE was assessed by point counting, and the lungs were classified as having pure CLE (C, n=5), predominant CLE with areas of PLE (CP, n=7), predominant PLE with features of CLE (PC, n=7), and pure PLE (P, n=6) according to the percentage of lung involved by either form. Preoperative pulmonary function tests and the score of inflammation and the diameters of the small airways were also measured.Mean linear intercept (Lm), a measure of mean interalveolar wall distances and forced expiratory volume in one second (FEV 1 ) were similar in the four groups. Small airway pathology was a predominant feature in lungs with CLE, and was significantly decreased in a stepwise fashion as the amount of PLE increased. This was especially so for the amount of muscle in the airway wall and the diameters of the airways. By contrast, lung compliance was higher in panacinar than in centrilobular emphysema.We conclude that: 1) smokers may reach similar values of airflow obstruction and parenchymal destruction in two completely different ways, developing either centrilobular or panacinar emphysema; 2) these two types of emphysema may be present in pure form or may overlap each other, but one type is always clearly predominant; and 3) the degree of either form has important consequences on the degree of airway abnormality and on the mechanical properties of the lung.

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Section: Emphysema Point Countingmentioning

confidence: 99%

Extent of centrilobular and panacinar emphysema in smokers' lungs: pathological and mechanical implications

Saetta¹,

Kim²,

Izquierdo³

et al. 1994

Eur Respir J

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“…The radii of alveoli range from approximately 0.12 to 0.18 mm (10,11) in humans to approximately 0.05 mm alveolar radius in rats (12). The duct size in humans range from 0.22 to 0.60 mm, depending on the generation (10), up to three times the size of an alveoli radius.…”

mentioning

confidence: 99%

Mapping of ³He apparent diffusion coefficient anisotropy at sub‐millisecond diffusion times in an elastase‐instilled rat model of emphysema

Boudreau

Ouriadov

et al. 2011

Magnetic Resonance in Med

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Hyperpolarized 3 He gas can provide detailed anatomical maps of the macroscopic airways in the lungs (i.e., ventilation) as well as insight into the lung microstructure through the apparent diffusion coefficient. In particular, the apparent diffusion coefficient of 3 He in the lung exhibits anisotropic effects that depend on diffusion time (d), and it has been shown to be extraordinarily sensitive to enlargement in terminal airways and alveoli associated with emphysema. In this study, the anisotropic nature of the 3 He apparent diffusion coefficient is studied in a rat model of emphysema, based on elastase instillation, specifically for d values less than one millisecond. Hyperpolarized helium 3 ( 3 He) MR imaging can provide both anatomical and functional information that may be important for diagnosing lung diseases. One of the most interesting implementations of 3 He imaging is diffusionweighted MR imaging, taking advantage of the much larger apparent diffusion coefficient (ADC) of 3 He compared to 1.1 Â 10 À5 cm 2 /s for hydrogen ( 1 H). 3 He diffusion in the lungs is restricted by airway and alveolar walls and therefore is highly dependent on lung microstructure. Diffusion measurements are sensitive to lung morphological information such as airway sizes and surface to volume ratio, by measuring the ADC that is largely dependent on lung geometry (1). This enables the tracking of disease progression, such as human chronic obstructive pulmonary disease (1,2) and asthma in mouse models (3). 3 He ADC has been shown to be sensitive to changes in terminal airway anatomy, specifically alveolar damage due to emphysema in both humans (1,4-6) and animal models (3,7-9).The lungs branch off from the trachea to bronchi, bronchioles, and eventually terminate at the alveolar sacs after approximately 25 divisions. The radii of alveoli range from approximately 0.12 to 0.18 mm (10,11) in humans to approximately 0.05 mm alveolar radius in rats (12). The duct size in humans range from 0.22 to 0.60 mm, depending on the generation (10), up to three times the size of an alveoli radius. In this geometry, diffusion is highly restricted for 3 He nuclei as the diffusion lengthis about 0.6 mm given a diffusion time (d) of 1.8 ms, which is typical of diffusion-weighted MR imaging. D 0 in Eq. 1 is the free diffusion coefficient and is equal to 1.91 Â 10 À4 m 2 /s (11) for pure 3 He at room temperature and 0.88 cm 2 /s when diluted in air. It has been shown that 3 He ADC obtained at millisecond diffusion times can distinguish normal from emphysematous tissue and correlates with mean linear intercept histology, an accepted measure of alveolar damage (12,13). 3 He ADC values obtained at sub-millisecond diffusion times (14) are expected to be even more sensitive to emphysema, especially in small animals. At longer diffusion times on the order of seconds, 3 He ADC is expected to reflect changes in lung anatomy over much larger length scales on the order of centimetres. Recent work has demonstrated ADC sensitivity to collateral pathway changes...

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“…However, geometric assumption-based estimates of alveolar number in the human lung have been shown to underestimate alveolar number, as evaluated by human acinar reconstructions (Hansen and Ampaya, 1975). These investigators identified six rather different geometric shapes in their acinar reconstructions.…”

mentioning

confidence: 99%

Total number and mean size of alveoli in mammalian lung estimated using fractionator sampling and unbiased estimates of the Euler characteristic of alveolar openings

et al. 2004

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Estimation of alveolar number in the lung has traditionally been done by assuming a geometric shape and counting alveolar profiles in single, independent sections. In this study, we used the unbiased disector principle to estimate the Euler characteristic (and thereby the number) of alveolar openings in rat lungs and rhesus monkey lung lobes and to obtain robust estimates of average alveolar volume. The estimator of total alveolar number was based on systematic, uniformly random sampling using the fractionator sampling design. The number of alveoli in the rat lung ranged from 17.3 ⅐ 10 6 to 24.6 ⅐ 10 6 , with a mean of 20.1 ⅐ 10 6 . The average number of alveoli in the two left lung lobes in the monkey ranged from 48.8 ⅐ 10 6 to 67.1 ⅐ 10 6 with a mean of 57.7 ⅐ 10 6 . The coefficient of error due to stereological sampling was of the order of 0.06 in both rats and monkeys and the biological variation (coefficient of variance between individuals) was 0.15 in rat and 0.13 in monkey (left lobe, only). Between subdivisions (left/right in rat and cranial/caudal in monkey) there was an increase in variation, most markedly in the rat. With age (2Ϫ13 years) the alveolar volume increased 3-fold (as did parenchymal volume) in monkeys, but the alveolar number was unchanged. This study illustrates that use of the Euler characteristic and fractionator sampling is a robust and efficient, unbiased principle for the estimation of total alveolar number in the lung or in well-defined parts of it. Anat Rec Part A 274A: 216 -226, 2004.

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Human air space shapes, sizes, areas, and volumes

Cited by 185 publications

References 0 publications

Extent of centrilobular and panacinar emphysema in smokers' lungs: pathological and mechanical implications

Extent of centrilobular and panacinar emphysema in smokers' lungs: pathological and mechanical implications

Mapping of ³He apparent diffusion coefficient anisotropy at sub‐millisecond diffusion times in an elastase‐instilled rat model of emphysema

Total number and mean size of alveoli in mammalian lung estimated using fractionator sampling and unbiased estimates of the Euler characteristic of alveolar openings

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Human air space shapes, sizes, areas, and volumes

Cited by 185 publications

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Extent of centrilobular and panacinar emphysema in smokers' lungs: pathological and mechanical implications

Extent of centrilobular and panacinar emphysema in smokers' lungs: pathological and mechanical implications

Mapping of 3He apparent diffusion coefficient anisotropy at sub‐millisecond diffusion times in an elastase‐instilled rat model of emphysema

Total number and mean size of alveoli in mammalian lung estimated using fractionator sampling and unbiased estimates of the Euler characteristic of alveolar openings

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Mapping of ³He apparent diffusion coefficient anisotropy at sub‐millisecond diffusion times in an elastase‐instilled rat model of emphysema