Diffusion-Weighted Magnetic Resonance Imaging for Predicting and Detecting the Early Response to Chemoradiotherapy of Advanced Esophageal Squamous Cell Carcinoma

Background: The aim of this study was to investigate the utility of the apparent diffusion coefficient (ADC) value in diffusion-weighted magnetic resonance imaging (DWMRI) for prediction and early detection of treatment response in advanced esophageal squamous cell carcinoma. Method: DWMRI was performed in 27 patients with primary cT4 esophageal carcinoma that were undergoing chemoradiotherapy before treatment and after 20 and 40 Gy. We calculated tumor ADCs and association of the treatment effect between responders and nonresponders. Results: The ADC at the time of 20 Gy was significantly higher in responders compared to nonresponders (1.13 vs. 0.93; p = 0.005). The ADC cut-off value was set at 1.00 × 10 -3 mm 2 /s and the ADC predicted the responders with a sensitivity, positive predictive value and accuracy of 79, 73 and 74%, respectively. The increased rate of the ADC at the time of 20 Gy (ΔADC20) was also significantly higher in responders compared to nonresponders (35.4 vs. 1.5%; p = 0.0007). An ADC cut-off value for ΔADC20 of 15% predicted the responders with a sensitivity, positive predictive value and accuracy of 71, 100 and 85%, respectively. Conclusion: The ADC values predicted the prognosis of patients with advanced esophageal squamous cell carcinoma as well as the treatment response.