Abstract: This paper evaluated the diagnostic value of diffusion-weighted imaging (diffusion-weighted magnetic resonance imaging, DWMRI) in peripheral non-small cell carcinoma (NSCLC) and evaluate the efficacy of radiotherapy and chemotherapy. From January 2016 to January 2019, 100 cases of NSCLC were treated in our hospital. The prescription dose of radiotherapy was 46~66 Gy, 2.0~2.2 Gy once a day, 5 times a week, combined with chemotherapy. CT and DWMRI, were used before and after radiotherapy and chemotherapy to observe the short-term curative effect, the high signal expression of DWMRI, the change of apparent diffusion coefficient (apparent diffusion coefficient,ADC) value and the prognostic factors. CT and MRI images were used to evaluate the curative effect of 100 patients with NSCLC before and after radiotherapy. There were 28 cases in CR group, 53 cases in PR group, 19 cases in NR group (PD 2 cases, SD 17 cases). The effective rate was 81.00% in CR group and PR group. The 3-year progression-free survival rates were 89.29%, 46.42%, 39.28% and 56.60%, 37.74%, 33.97%, respectively (χ²=24.500,P=0.000). After radiotherapy, DWMRI hyperintensity disappeared in 35 cases and did not disappear in 65 cases, lymph node hyperintensity disappeared in 40 cases and not completely disappeared in 35 cases, primary focus of lung cancer in 18 cases, lymph node completely disappeared in 29 cases. The 1,2,3-year progression-free survival rates of NSCLC patients were 71.25%, 34.52%, 25.00% and 35.64%、4.50%、4.50%, respectively. (χ²=25.790,P=0.000). The CR, PR, NR group's ADC value of primary focus and metastatic lymph node increased gradually before radiotherapy, but Δ ADC value decreased gradually. After radiotherapy, the therapeutic effect of CR group was the best, PR group was better than NR group (P<0.05). In the group of complete disappearance of high signal, the ADC value of the primary focus before and after radiotherapy was lower than that of the group of partial disappearance of high signal, but the value of Δ ADC was higher than the group of partial disappearance of high signal. ADC and Δ ADC were significantly higher in patients with complete disappearance of metastatic lymph nodes before and after radiotherapy than those in patients with partial disappearance of hyperintense lymph nodes (P<0.05). Multivariate analysis of prognostic factors by Cox regression model. It was found that TNM stage and DWMRI were the main prognostic factors. This research shows that DWMRI is sensitive to the changes of microenvironment in the treatment of tumors, and the change of ADC is worthy of monitoring the effect of tumor diagnosis in the early stage, which can provide a better evaluation for the treatment and diagnosis of clinical NSCLC.

Key words: DWMRI, peripheral non-small cell carcinoma (NSCLC), diagnosis, efficacy of radiotherapy and chemotherapy