Neoadjuvant chemotherapy (NAC) is one of the important treatment strategies for breast cancer, which can lower the clinical stage and facilitate breast conserving surgery. Evaluating the effect of NAC accurately by using image technology plays a key role. Magnetic resonance imaging (MRI) is an assessment technique with high susceptibility and sensitivity, which can not only evaluate the effect from morphology, but can provide timely and useful information in the efficacy evaluation of NAC in breast cancer through diffusion-weighted imaging (DWI), dynamic contrast enhanced MRI (DCE-MRI), perfusion-weighted imaging (PWI).

Objective To evaluate the value of 3.0T magnetic resonance multi-b value diffusion-weighted imaging (DWI) in evaluating the efficacy of chemotherapy for patients with central lung squamous cell carcinoma and atelectasis. Methods Twenty patients with lung squamous cell carcinoma were examined by magnetic resonance imaging (MRI) (including T1WI, T2WI and multi-b value DWI) before chemotherapy, 2 cycles of chemotherapy and 4 cycles of chemotherapy. The images, the tumor volume and changes of apparent diffusion coefficient (ADC) were analyzed. Results In the patients with central lung cancer and atelectasis, the tumor and atelectasis could be distinguished on MRI examination before radiotherapy. It was more easily identified on T2WI images after radiotherapy. In the 20 patients, the ADC values in the effective group (partial remission or complete remission) and the invalid group were increased, but the differences of ADC values in the effective group before chemotherapy, 2 cycles and 4 cycles of chemotherapy were statistically significant [b=800 s/mm2:(1.09 ± 0.52) × 10-6 mm2/s, (1.22 ± 0.59) × 10-6 mm2/s, (1.24 ± 0.52) × 10-6 mm2/s, F = 31.19, P < 0.001]. There was no significant difference in ADC values between before and after chemotherapy (b = 800 s/mm2: (1.10 ± 0.49) × 10-6 mm2/s, (1.16 ± 0.60) × 10-6 mm2/s, (1.20 ± 0.72) × 10-6 mm2/s, F=2.86, P=0.089]. When b=800 s/mm2, the ADC curve slope in the effective group was more stable, better linearity. Conclusions The MRI technique can accurately distinguish the tumor from atelectasis before and after chemotherapy. The change of ADC value after chemotherapy is earlier than that of morphological change. The change rate of b value can better evaluate the curative effect of chemotherapy.