Low- and High-Attenuation Lung Volume in Quantitative Chest CT in Children without Lung Disease

Abstract

In contrast to studies of adults with emphysema, application of fixed thresholds to determine low- and high-attenuation areas (air-trapping and parenchymal lung disease) in pediatric quantitative chest CT is problematic. We aimed to assess age effects on: (i) mean lung attenuation (full inspiration); and (ii) low and high attenuation thresholds (LAT and HAT) defined as mean attenuation and 1 SD below and above mean, respectively. Chest CTs from children aged 6–17 years without abnormalities were retrieved, and histograms of attenuation coefficients were analyzed. Eighty examinations were included. Inverse functions described relationships between age and mean lung attenuation, LAT or HAT (p < 0.0001). Predicted value for LAT decreased from −846 HU in 6-year-old to −950 HU in 13- to 17-year-old subjects (cut-off value for assessing emphysema in adults). %TLCCT with low attenuation correlated with age (rs = −0.31; p = 0.005) and was <5% for 9–17-year-old subjects. Inverse associations were demonstrated between: (i) %TLCCT with high attenuation and age (r2 = 0.49; p < 0.0001); (ii) %TLCCT with low attenuation and TLCCT (r2 = 0.47; p < 0.0001); (iii) %TLCCT with high attenuation and TLCCT (r2 = 0.76; p < 0.0001). In conclusion, quantitative analysis of chest CTs from children without lung disease can be used to define age-specific LAT and HAT for evaluation of pediatric lung disease severity.

Analysis of CT Numbers in Thoracic CT Scan Image Segmentation and Spirometry on Pulmonary Vital Capacity

“…One way to calculate lung volume is to limit the area (segmentation) of the lung organ and the value of range Hounsfield (HU), Which is used to organ lungs. On condition emphysema, the Hounsfield unit value shown is less than -950 HU at the time of the inspiration (Moutafidis et al, 2021); (Camiciottoli et al, 2006); (Wu et al, 2021); (Mohamed Hoesein et al, 2012).…”