Application of diffusion-weighted magnetic resonance imaging in precise radiotherapy for esophageal carcinoma

Abstract

Objective To explore the application of diffusion-weighted magnetic resonance imaging (DWMRI) in precise radiotherapy of esophageal carcinoma.Methods Thirty-seven patients with biopsy proven esophageal cancer from March 2010 to January 2011 were included.To delineate the gross tumor volume (GTV) using CT and DWMRI images,each patient was examined by DWMRI and CT scan using the same position before radiotherapy.To compare the maximum diameters and volumes of tumor between CT and DWMRI. The tumor lengths measured by esophagogram,esophagoscope,CT and DWMRI were compared.Results Tumor lengths under esophagogram,esophagoscope,CT and DWMRI were 5.70 cm,6.06 cm,7.97 cm and 5.79 cm respectively. The lengths between CT and esophagogram,CT and esophagoscope,CT and DWMRI had statistical significance respectively (F=4.88,P=0.003).The maximum diameters of tumor shown on CT and DWMRI were 3.79 cm and 3.81 cm respectively ( t =-0.32,P=0.751 ).The GTV were 45.75 cm3 and 38.05 cm3 in CT and DWMRI respectively (t=5.30,P =0.001 ).53 lymph nodes were assessed positive on both CT and DWMRI.DWMRI excluded 25 positive lymph nodes assesed by CT; also confirmed 15 negative lymph nodes excluded by CT,6 of which were paraesophageal lymph nodes.The addition of DWMRI information altered the clinical stage in 6 patients.Conclusions Tumor lengths measured on DWMRI and esophagogram had the optimal approximation.It was easy to find paraesophageal lymph nodes via DWMRI.With the addition of DWMRI information,the target range and clinical stage were alerted in some patients. Key words: diffusion-weighted magnetic resonance imaging; Esophageal neoplasms; Neoplasm staging; Target volume delineation