The value of intravoxel incoherent motion diffusion-weighted imaging in predicting the pathologic response to neoadjuvant chemotherapy in locally advanced esophageal squamous cell carcinoma

Objective To explore the value of intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) for the prediction of pathologic response to neoadjuvant chemotherapy (NAC) in locally advanced esophageal squamous cell carcinoma (ESCC). Material and methods Forty patients with locally advanced ESCC who were treated with NAC followed by radical resection were prospectively enrolled from September 2015 to May 2018. MRI and IVIM were performed within 1 week before and 2-3 weeks after NAC, prior to surgery. Parameters including apparent diffusion coefficient (ADC), true diffusion coefficient (D), pseudodiffusion coefficient (D*), and pseudodiffusion fraction (f) before and after NAC were measured. Pathologic response was evaluated according to the AJCC tumor regression grade (TRG) system. The changes in IVIM values before and after therapy in different TRG groups were assessed. Receiver operating characteristic (ROC) curves analysis was used to determine the best cutoff value for predicting the pathologic response to NAC. Results Twenty-two patients were identified as TRG 2 (responders), and eighteen as TRG 3 (non-responders) in pathologic evaluation. The ADC,D, andfvalues increased significantly after NAC. The post-NACDand Delta Dvalues of responders were significantly higher than those of non-responders. The area under the curve (AUC) was 0.722 for post-NAC D and 0.859 for Delta Din predicting pathologic response. The cutoff values of post-NAC D and Delta D were 1.685 x 10(-3) mm(2)/s and 0.350 x 10(-3) mm(2)/s, respectively. Conclusion IVIM-DWI may be used as an effective functional imaging technique to predict pathologic response to NAC in locally advanced ESCC.

Automated summary

IVIM-DWI can be an effective functional imaging technique in predicting pathologic response to NAC in locally advanced ESCC, with significant increases in ADC, D, and f values post-NAC and higher D and Delta D values in responders compared to non-responders.