ABSTRACT
Objective To investigate the ADC value and intravoxel incoherent motion (IVIM) parameters to predict the early response to chemotherapy in patients with locally advanced non-small cell lung cancer (NSCLC). Methods Twenty-six patients with pathologically confirmed NSCLC in our hospital from June 2015 to January 2017 were prospectively studied. MR routine scan, DWI and IVIM scans were performed before and at the end of the first cycle of chemotherapy. The ADC value, pure diffusion parameter (D), perfusion parameter (D*) and perfusion fraction (f) before and after chemotherapy were recorded respectively, and the maximum diameter of tumor (MDMRI) was measured on T2WI. The effective group and the ineffective group were divided according to RECIST 1.1. Intra- and interobserver reproducibility were assessed with intraclass correlation coefficient (ICC). The differences of the parameters and their change rate were compared pre-and posttreatment, in the effective and the ineffective groups by using t test. Receiver operating characteristic (ROC) curves were generated to explore the optimal parameters and thresholds for early prediction of the efficacy of chemotherapy. Z test was used to compare the differences in the areas under the ROC curves. Results The repeatability of D*was relatively poor (ICC 0.507-0.716). The ADC and D values of the effective group before chemotherapy were (1.28±0.21)×10-3 and (1.05±0.14)×10-3mm2/s, respectively, and those of the ineffective group were (1.55 ± 0.25) × 10-3 and (1.29 ± 0.18) × 10-3mm2/s, respectively. The differences between two groups were statistically significant (t=-2.989, -3.755, respectively, P all<0.05). While there was no significant difference in f between the effective and ineffective groups before chemotherapy (t=-1.034, P=0.312). The ADC, D and f values of the effective group before chemotherapy were lower than those after chemotherapy, and the differences were statistically significant (t=-3.969,-5.617 and-2.876, respectively, P all<0.05). While there was no significant difference in ADC and D values in ineffective group (t=-0.737, -0.866, P>0.05, respectively). The difference of f was statistically significant (t=-2.731, P<0.05).ΔADC％,ΔD％andΔMDMRI％in effective group were (23.90 ± 22.28)％, (32.58 ± 20.63)％ and (18.77 ± 10.36)％, respectively, and those in ineffective group were (1.19 ± 11.35)％, (6.22 ± 21.63)％ and (9.35 ± 8.26)％, respectively. The differences between two groups were statistically significant (t=3.393, 3.154 and 2.487, respectively, P all<0.05). There was no significant difference inΔf％between two groups (t=1.346, P=0.191). ROC curve analysis showed that the area under curve (AUC) of preADC, preD, ΔADC％, ΔD％ and ΔMDMRI％ was 0.788, 0.848, 0.800, 0.830 and 0.727, respectively. When setting the preD=1.20×10-3 mm2/s as the boundary under the largest AUC, however, there was no significant differences in AUC compared with preADC, ΔADC％, ΔD％ and ΔMDMRI％ (Z=1.336, 0.363, 0.136, 1.395, P>0.05). Conclusion The ADC value, D value before chemotherapy and the early change rate after chemotherapy can better predict the early response of chemotherapy in NSCLC patients.