A Primary Study Of Spectral CT Imaging In Detecting The Perfusion Defects Of Pulmonary Parenchyma In Patients With Central Lung Cancer

Objective To evaluate the capability of spectral CT imaging in detecting the lung perfusion defects induced by central lung cancer, and to compare the correlation between the lung perfusion defects and the central pulmonary artery involvement from central lung cancer.Methods Thirty patients with central lung cancer underwent enhanced CT with gemstone spectral imaging (GSI) mode.Then the monochromatic CTA imaging and iodine-based material decomposition imaging were obtained. The central pulmonary artery involvement was comprehensive evaluated in the monochromatic CTA images including multiplanar reformation(MPR) and maximum intensity projection (MIP), then score method of five grades was applied to evaluate the central pulmonary artery involvement. On the iodine-based material decomposition images, iodine concentration were measured and compared between in periphery of the central lung cancer and in corresponding area of the contralateral normal lung; then the descent rate of iodine concentration in periphery of the central lung cancer was calculated. The correlation between the score of central pulmonary artery involvement and the descent rate of iodine concentration was analyzed.Results In thirty patients with central lung cancer, there were 66 central arteries involvement, the number of the pulmonary trunk involvement is 12, the number of the lobar artery involvement is 29, the number of the segmental artery is 25.The number of score one is 15, the number of score two is 19, the number of score three is 31, the number of score four is 1. The mean score was 2.21. The iodine concentration (0.73±0.38 mg/mL) in periphery of the central lung cancer was significantly lower than that (1.45±0.57 mg/mL) in corresponding area of the contralateral normal lung (t=-9.23, P<0.001).The range of the descent rate of iodine concentration in periphery of the central lung cancer was from 14.5% to 87.2%.There was a significantly positive correlation between the mean score of central artery involvement and the descent rate of iodine concentration(r=0.94, P<0.001).Conclusion Spectral CT imaging can not only identify perfusion defects that are induced by central lung cancer., but also evaluate quantitatively the lung perfusion defects induced by the central pulmonary artery involvement differently from central lung cancer.