Computed Tomographic Measurements of Airway Dimensions and Emphysema in Smokers

Abstract

Chronic obstructive pulmonary disease (COPD) is characterized by the presence of airflow obstruction caused by emphysema or airway narrowing, or both. Low attenuation areas (LAA) on computed tomography (CT) have been shown to represent macroscopic or microscopic emphysema, or both. However CT has not been used to quantify the airway abnormalities in smokers with or without airflow obstruction. In this study, we used CT to evaluate both emphysema and airway wall thickening in 114 smokers. The CT measurements revealed that a decreased FEV(1) (%predicted) is associated with an increase of airway wall area and an increase of emphysema. Although both airway wall thickening and emphysema (LAA) correlated with measurements of lung function, stepwise multiple regression analysis showed that the combination of airway and emphysema measurements improved the estimate of pulmonary function test abnormalities. We conclude that both CT measurements of airway dimensions and emphysema are useful and complementary in the evaluation of the lung of smokers.

Ventilation Heterogeneity in Ex-smokers without Airflow Limitation

“…We observed significant correlations between airway morphology and VDP in the RUL and RLL. Previous studies (25,26) have shown that RUL and RLL airway morphology is significantly correlated with whole-lung function (assessed by spirometry) in COPD, but these studies did not investigate regional relationships with function. The observation that thickened airway walls and narrowed airway lumens correlate with increasing ventilation heterogeneity in the RUL, and RLL suggests that there may be a structure-function relationship between airway morphology and ventilation in exsmokers.…”

Computed tomographic imaging of the airways: relationship to structure and function

“…NIIMI et al [72] showed progressive thickening of the wall of the right apical segmental bronchus in asthmatics as a function of disease severity (baseline FEV1), but, surprisingly, there was no difference in the luminal area of this airway in the severe asthmatics compared with the control subjects or mild asthmatics. Interestingly, for a given degree of airflow obstruction, the airway wall of the right apical bronchus is substantially thicker in asthmatics compared with COPD patients [18,72].…”

“…2) [18,19]. Although this method provides a standardised and unbiased measurement, it has limitations.…”

“…The process that causes the small airway obstruction in COPD is inflammatory in nature and characterised by thickening of all the layers of the bronchiolar walls, as well as an accumulation of mucus in the airway lumen [23]. NAKANO et al [18] measured lung attenuation and the dimensions of the right upper lobe apical segmental bronchus in 114 smokers, using the half-max method. Ninety-four of the smokers were obstructed (FEV1 37¡15% predicted), whereas 20 were unobstructed (mean FEV1 100¡13% pred), despite having a comparable smoking history.…”

Association of fucosyltransferase 8 (FUT8) polymorphism Thr267Lys with pulmonary emphysema

“…Severity of emphysema was determined from high-resolution computed tomography (HRCT) scans obtained at full inspiration. The percentage of the low attenuation area (%LAA) was calculated to assess the extent of emphysema, using HRCT scans according to Nakano et al, 12 with a minor modification. Briefly, six slices were obtained from the bilateral lungs at the upper, middle and lower lobes.…”