A comparative analysis of CT features and pathological types of small lung invasive adenocarcinoma with air-containing space / 中华放射学杂志

ABSTRACT

Objective@#To evaluate the CT features of small lung invasive adenocarcinoma with air-containing space and its relationship with pathological types, and to explore the pathological basis of air-containing space.@*Methods@#CT and pathological data of fifty patients with surgically proven lung invasive adenocarcinoma with air-containing space in our hospital from January 2012 to December 2017 were retrospectively reviewed. CT image analysis included image features of tumor and air-containing space. Pathological analysis included pathological subtype, differentiation degree. CT features of tumor and air-containing space were compared with regard to pathological types using chi-square test or Fisher exact text. Analysis of variance was used to compare quantitative data satisfying normal distribution, while those data not satisfying normal distribution were compared with Kruskal-Wallis test. In addition, Spearman correlation was used to analyze the correlation between nodule density and pathological types.@*Results@#(1) CT features of tumors: Tumors were predominantly located in peripheral lungs (46/50). Most of the tumors were subsolid nodules (37/50). Tumor-lung interface was generally clear (46/50). Tumors are often accompanied by malignant signs such as lobulation (37/50), spicule sign (27/50), air bronchogram sign (43/50), and pleural indentation (36/50). The mean diameter of nodules ranged from 7.50 mm to 18.12 mm, with an average of (12.91±2.85)mm. The nodule density ranged from-657.00 to 73.00 HU with an average of (-213.88±206.16) HU. (2) CT features of air-containing space: Air-containing spaces were commonly solitary (37/50) and were found to be mainly in an eccentric distribution (29/37). The maximum diameter of air-containing space ranged from 1.00 to 16.00mm, and the average diameter was (4.23±3.14)mm. Air-containing spaces less than 5mm were found in 35 cases (70%), and air-containing spaces more than 5mm were found in 15 cases. (3) Comparison of CT features and corresponding pathological types: Nodule density, number of air-containing space, and type of nodule density in different pathological types were statistically different (P<0.05). There was a correlation between nodule density and pathological subtypes (r=0.371, P=0.008). Differences of nodule density, short-dimension of nodule, type of nodule density, spicule sign, pleural indentation among different tumor differentiation degrees were significant (P<0.05). The degree of tumor differentiation was negatively correlated with nodule density (r=-0.451, P=0.001).@*Conclusion@#The detection rate of air-containing space in lung invasive adenocarcinomas is 12.7%. Most small lung invasive adenocarcinomas with air-containing space are presented as peripheral subsolid nodule, and there is a certain correlation between their CT features and pathological types. The pathological basis of air-containing space was supposed to be dilated distal bronchiole induced by check-valve mechanism and destruction of alveolar structure by tumor.