Application value of double-layer spectral detector CT in differentiating central lung cancer from atelectasis / 中华放射学杂志

ABSTRACT

Objective:To evaluate the application value of double-layer spectral detector CT (DLSDCT) in differentiating central lung cancer from atelectasis.Methods:Fifty-one patients with central lung cancer accompanied by atelectasis confirmed by pathology in Shandong Cancer Hospital from January to December 2020 were enrolled. The differentiating rates of tumor from atelectasis of the conventional CT, 40 keV virtual monoenergetic imaging (MonoE), iodine density map (ID), and 40 keV MonoE-ID fusion images of unenhanced scan, arterial and venous phase were retrospectively analyzed. Cochran′s Q test was used to compare the differentiating rate (Bonferroni correction afterwards), and Friedman test was used to compare the maximum diameter of the tumor of each imaging method.Results:Of the 51 patients, none of the conventional CT images, 40 keV MonoE, ID and 40 keV MonoE-ID fusion images in the unenhanced scan could distinguish lung tumors from atelectasis; the number of cases in which the conventional CT images, 40 keV MonoE, ID and 40 keV MonoE-ID fusion images in the arterial phase could distinguish lung tumors from atelectasis regions was 4, 5, 5 and 6, respectively; the number of cases in which the conventional CT, 40 keV MonoE, ID and 40 keV MonoE-ID fusion images in the venous phase could distinguish lung tumors from atelectasis regions was 17, 35, 39 and 38, respectively, and the difference was statistically significant (χ 2=52.40, P<0.001). The differentiating rates of the 40 keV MonoE, ID, and 40 keV MonoE-ID fusion image were significantly higher than that of conventional CT image (χ2=-0.35, -0.43, -0.41, P<0.001, Bonferroni correction afterwards); There was no significant difference in the differentiating rate among 40 keV MonoE, ID and MonoE-ID fusion image ( P=1.00). Seventeen tumors could be differentiated in conventional CT images, 40 keV MonoE, ID and 40 keV MonoE-ID fusion images of venous phase, and the maximum diameters of lung tumors were (50±21) mm, (50±23) mm, (50±23) mm, and (50±23) mm, respectively, and the difference was not statistically significant (χ2=3.61, P=0.31). Conclusions:The venous phase spectral images of DLSDCT can differentiate most central lung cancer from atelectasis. Therefore, it has great clinical application value in tumor staging, efficacy evaluation, and radiotherapy.