Evaluation of quantitative CT indexes in idiopathic interstitial pneumonitis using a low-dose technique

Abstract

Objective To evaluate and compare histogram features (mean lung attenuation, skewness, kurtosis) of low-dose and standard-dose CT in a group of patients affected by idiopathic interstitial pneumonitis. Methods We analyzed 16 patients affected by idiopathic interstitial pneumonitis. Spiral whole lung thin-section CT acquisition at standard dose (100 mAs) and three additional low-dose (50 mAs) CT images were obtained. After obtained frequency histograms, mean lung attenuation (MLA), skewness and kurtosis and three range of density (−700/−200 HU; −700/−400 HU; −500/−200 HU) of the standard-and low-dose thin-section CT scans were analyzed and compared. Results The parameters obtained with low-dose and standard-dose spiral CT were correlated in a highly significant manner and were equivalent ( p < 0.01). The greatest correlation was found between standard-and low-dose kurtosis and standard and low-dose −700/−400 HU subrange of density ( r = 0.92; p < 0.0001). Conclusions Our results prove that a quantitative CT objective evaluation in lung fibrosis can be successfully obtained with low-dose spiral CT, with reduced mA.