The application of DW-MRI in the staging of oesophageal cancer: prospective comparison with EUS and MDCT

Purpose: To prospectively compare the diagnostic performance of diffusion - weighted magnetic resonance (DW -MR), multidetector computed tomography (MDCT) and endoscopic ultrasound (EUS) in the preoperative loco -regional staging of oesophageal cancer. Methods and Materials: Eighteen patients with biopsy -proved oesophageal tumour (9 directly treated with surgery and 9 addressed t o chemo/radiotherapy before) underwent 1.5 T DW -MRI, 64 -channels MDCT and EUS before and after neoadjuvant treatment. All images were analysed blindly by dedicated operators and two radiologists calculated independently the ADC from the first scan. Results were then compared with surgical findings. Spearman and intraclass correlation coefficients, Mann- Whitney and ROC curves analysis were performed. The population was divided into T1 -2 vs T3 -4 and N0 vs N+. Sensitivity, specificity, accuracy, positive and negative predictive value were calculated and compared for each technique. Results: For T staging, EUS showed the best sensitivity (100%) while MR showed the highest specificity (92%) and accuracy (83%). For N staging, MR and EUS showed the highest sensitivity (100%) but none of the three techniques showed adequate results for specificity. Overall, MR showed the highest accuracy (66%) for N stage. Mean ADC was different between surgery - only and chemo/radiotherapy groups (1.90 vs 1.30 x 10-3 mm2/s, respective ly; p= 0.005), with an optimal cut off for local invasion of 1.33 x 10-3 mm2/s (p=0.05). Conclusion: DW -MR could improve the current preoperative staging workup for oesophageal cancer, showing characteristic advantages for both staging and initial treatment decision -making.