Abstract： Objective:To evaluate the feasibility of quantitative parameters based on T1 mapping sequence in predicting the pathological types of lung cancer.Materials and Methods:A total of 117 lung cancer patients,including 62 cases of adenocarcinoma,26 cases of squamous cell carcinoma,29 cases of small cell lung cancer(SCLC),were enrolled in this study.Prior routine sequence scans,then the B1 field corrected variable flip angle VIBE sequence was used to acquire T1 mapping images.Afterwards,Gd-DTPA was used for dynamic enhanced scanning.T1 mapping images were collected 5 minutes before and after enhancement.Measure tumor size,T1 value before enhancement(T1pre),T1 value after enhancement(T1post),and calculate ΔT1,ΔT1%.SPSS and MedCalc software were used for analysis the differential diagnostic value of each quantitative parameter in each group,logistic regression combined with area under the curve(AUC)was constructed to evaluate the diagnostic value of each quantitative parameter and multi-parameter combination.Results:There were statistically significant differences in ΔT1,ΔT1%and T1post among adenocarcinoma,squamous cell carcinoma and SCLC(P＜0.05),but no difference in T1pre(P=0.506).The AUCs of T1post,ΔT1,and ΔT1%values to differentiate SCLC and non-small cell lung cancer(NSCLC)were 0.856,0.805 and 0.864,combination of the three parameters can improve the diagnostic accuracy of differentiating SCLC and NSCLC(AUC=0.870,P＜0.05).The AUCs of ΔT1 and ΔT1%values to differentiate adenocarcinoma and squamous cell carcinoma were 0.755 and 0.767,combination of the two could slightly improve the diagnostic accuracy(AUC=0.771,P＞0.05).The AUCs of ΔT1%,T1post values to differentiate squamous cell carcinoma and SCLC were 0.788 and 0.818,combination of the two could improve the diagnostic accuracy(AUC=0.831,P＞0.05).The AUCs of ΔT1%,T1post values to differentiate adenocarcinoma and SCLC is 0.895 and 0.873,combination of the two could improve the diagnostic accuracy(AUC=0.898,P＞0.05).Conclusions:T1 mapping can non-invasively and quantitatively obtain the T1 value of adenocarcinoma,squamous cell carcinoma and small cell lung cancer,and can be used to distinguish SCLC from NSCLC,as well as squamous cell carcinoma and adenocarcinoma,provide more accurate histological correlations and prognostic value in lung cancer.