Structural and Functional Features on Quantitative Chest Computed Tomography in the Korean Asian versus the White American Healthy Non-Smokers

OBJECTIVE: Considering the different prevalence rates of diseases such as asthma and chronic obstructive pulmonary disease in Asians relative to other races, Koreans may have unique airway structure and lung function. This study aimed to investigate unique features of airway structure and lung function based on quantitative computed tomography (QCT)-imaging metrics in the Korean Asian population (Koreans) as compared with the White American population (Whites). MATERIALS AND METHODS: QCT data of healthy non-smokers (223 Koreans vs. 70 Whites) were collected, including QCT structural variables of wall thickness (WT) and hydraulic diameter (Dh) and functional variables of air volume, total air volume change in the lung (ΔVair), percent emphysema-like lung (Emph%), and percent functional small airway disease-like lung (fSAD%). Mann-Whitney U tests were performed to compare the two groups. RESULTS: As compared with Whites, Koreans had smaller volume at inspiration, ΔVair between inspiration and expiration (p < 0.001), and Emph% at inspiration (p < 0.001). Especially, Korean females had a decrease of ΔVair in the lower lobes (p < 0.001), associated with fSAD% at the lower lobes (p < 0.05). In addition, Koreans had smaller Dh and WT of the trachea (both, p < 0.05), correlated with the forced expiratory volume in 1 second (R = 0.49, 0.39; all p < 0.001) and forced vital capacity (R = 0.55, 0.45; all p < 0.001). CONCLUSION: Koreans had unique features of airway structure and lung function as compared with Whites, and the difference was clearer in female individuals. Discriminating structural and functional features between Koreans and Whites enables exploration of inter-racial differences of pulmonary disease in terms of severity, distribution, and phenotype.

Comparison of Filtered Back Projection, Hybrid Iterative Reconstruction, Model-Based Iterative Reconstruction, and Virtual Monoenergetic Reconstruction Images at Both Low- and Standard-Dose Settings in Measurement of Emphysema Volume and Airway Wall Thick

OBJECTIVE: To evaluate the accuracy of emphysema volume (EV) and airway measurements (AMs) produced by various iterative reconstruction (IR) algorithms and virtual monoenergetic images (VME) at both low- and standard-dose settings. MATERIALS AND METHODS: Computed tomography (CT) images were obtained on phantom at both low- (30 mAs at 120 kVp) and standard-doses (100 mAs at 120 kVp). Each CT scan was reconstructed using filtered back projection, hybrid IR (iDose4; Philips Healthcare), model-based IR (IMR-R1, IMR-ST1, IMR-SP1; Philips Healthcare), and VME at 70 keV (VME70). The EV of each air column and wall area percentage (WA%) of each airway tube were measured in all algorithms. Absolute percentage measurement errors of EV (APEvol) and AM (APEWA%) were then calculated. RESULTS: Emphysema volume was most accurately measured in IMR-R1 (APEvol in low-dose, 0.053 ± 0.002; APEvol in standard-dose, 0.047 ± 0.003; all p 0.05). VME70 showed a significantly higher APEvol than iDose4, IMR-R1, and IMR-ST1 (all p < 0.004). VME70 also showed a significantly higher APEWA% compared with the other algorithms (all p < 0.001). CONCLUSION: IMR was the most accurate technique for measurement of both EV and airway wall thickness. However, VME70 did not show a significantly better accuracy compared with other algorithms.

Influential factors of airflow limitation in patients with chronic obstructive pulmonary disease:an analysis using quantitative CT / 实用放射学杂志

Objective To evaluate the correlations of emphysema and airway wall thickness to chronic obstructive pulmonary disease(COPD) of airflow limitation by quantitative CT.Methods 40 COPD patients and other 40 normal controls underwent pulmonary function tests and following MSCT exams with inspiration.The square root of wall area of an airway with an internal area of 8 mm2 (Ai8) and the percentage of low attenuation volume(LAV%) of the whole lung and each lobes at the threshold of-950 HU were measured by a software of Thoracic VCAR.The Ai8 between the observation group and the control one was compared using SPSS2.2.The contributions of LAV% and Ai8 to predictions of FEV1/FVC and FEV1% were also evaluated.Results There was a significantly statistical difference in the Ai8 between the observation group and the control one.There were correlations between airflow limitation markers and all of LAV% as well as Ai8 (P<0.05 for all standardized coefficients).Only the Ai8 of right inferior lobar made a significant contribution to airflow limitation in the whole lung bronchus, and the LAV% of each lobes made a stronger contribution to airflow limitation than the Ai8 of right inferior lobe.Conclusion There is a significantly statistical difference in the Ai8 between the observation group and the control one.The LAV% may make a greater contribution to airflow limitation than Ai8 in COPD group.The influential factors of airflow limitation in order were LAV%, Ai8 of right inferior lobe and Ai8 of the other lobes.

High resolution computed tomographic assessment of airway remodeling: comparison according to the severity of asthma / 대한내과학회지

BACKGROUND: Airway remodeling is characterized by an increase in the airway wall thickness. We aimed to compare the airway wall thickness among asthmatic subjects with different severity and to examine its relation to pulmonary function and airway hyperresponsiveness. METHODS: Thirty-seven adult asthmatics were assigned to mild (MA, n=17), moderate (MoA, n=11), and severe (SA, n=9) groups according to the Global Initiative for Asthma classification. Patients with more than 10 pack-years of smoking history were excluded. We measured the airway wall thickness (T) and internal diameter (d) using high-resolution computed tomography, and then calculated the external diameter (D). The T/D ratio was compared between the groups and correlations between the T/D ratio and pulmonary function (methacholine PC20) were assessed. RESULTS: The mean T/D ratio was significantly higher in the MoA and the SA groups than in the MA group for the total airways (0.278+/-0.014, 0.281+/-0 .019 vs. 0.228+/-0.013; p=0.022, p=0.021, respectively). The mean T/D ratio was also higher in the SA group than the MA group for the small airways (0.313+/-0.018 vs. 0.253+/-0.013; p=0.009). However, there were no significant differences for the large airways. The mean T/D ratio negatively correlated with FEV1 (L) and FEV1 (% of predicted) in total airways (r=-0.519, p=0.001; r=-0.396, p=0.015), small airways (r=-0.567, p<0.001; r=-0.450, p=0.008) and large airways (r=-0.395, p=0.015; r=-0.351, p=0.033). The methacholine PC20 was not related to the T/D ratio. CONCLUSIONS: This study suggests that patients with moderate to severe asthma have greater airway remodeling than those with mild asthma, and the degree of airway wall thickening correlates to the severity of airflow obstruction.

Airway wall thickness and pulmonary functions in patients with bronchial asthma: Assessment with high resolution computed tomography (HRCT) / 천식및알레르기

BACKGROUND: The presence of airway wall thickening and its relationship with pulmonary functions or airway hyperresponsiveness (AHR) have not yet been sufficiently clarified in bronchial asthma. OBJECTIVE: We investigated the relation of airway wall thickness to the pulmonary functions and AHR in patients with asthma. METHODS: After baseline measurement of pulmonary functions and PC20 in 24 patients, we measured airway wall thickness (T), internal diameter (d) using HRCT and calculated external diameter (D)[(D)=(d)+ 2x(T)]. We used the T/D ratio as a parameter for comparisons with pulmonary functions and PC20. RESULTS: We measured total 185 airways (upper;92, lower;93). The mean T/D ratio of small airways (diameteror=2mm;n=74) (0.324 +/- 0.028 vs 0.274 +/- 0.033, p<0.001). The mean T/D ratio of each subjects showed significant negative correlation with FEV1(% of predicted) in total (r=-0.407, p=0.048) and small airways (r=-0.468, p=0.024). PC20 showed a tendency of weak negative correlation with mean T/D ratio in small airways (r=-0.290, p=0.179). CONCLUSION: The thicker the airway wall is, the lower the FEV1 (% of predicted) in patients with bronchial asthma. Airway wall thickening occurred predominantly in the small airways.