Objective To compare the application value of ¹⁸F-fluorodeoxyglucose (FDG) PET/MRI and MRI in the preoperative T and N staging of patients with esophageal cancer.

Methods The clinical and imaging data of 30 patients who underwent radical resection for esophageal cancer in the Second Affiliated Hospital of the Air Force Military Medical University from January 2018 to December 2019 were retrospectively analyzed. The sample included 25 males and 5 females, aged 42–77(62.9±8.0) years old. All patients underwent ¹⁸F-FDG PET/MRI examination within 2 weeks before operation, and the postoperative histopathological examination results were used as the “gold standard” for staging. The Kappa test was employed to evaluate the consistency of ¹⁸F-FDGPET/MRI and MRI in the preoperative T and N staging of patients with esophageal cancer and in postoperative histopathological staging. The staging accuracy was compared using the χ² test, and the values of the maximum standardized uptake (SUV_max), mean standardized uptake (SUV_mean), apparent diffusion coefficient minimum vaalue (ADC_min), and apparent diffusion coefficient mean value (ADC_mean) of metastatic lymph nodes and benign lymph nodes were compared using independent sample t test.

Results ¹⁸F-FDG PET/MRI and MRI showed strong consistency in the preoperative T staging and postoperative histopathological staging of patients with esophageal cancer (Kappa value=0.757, 0.698; both P<0.001). The accuracy rates of ¹⁸F-FDG PET/MRI and MRI in the diagnosis of preoperative T staging in patients with esophageal cancer were 83.3% (25/30) and 80.0% (24/30) respectively, with no significant difference (χ²=0.110, P>0.05). The diagnostic accuracy of ¹⁸F-FDG PET/MRI for preoperative N staging in patients with esophageal cancer was higher than that of MRI (76.7% (23/30) vs. 66.7% (20/30)), and the difference was statistically significant (χ²=11.273, P<0.01). The SUV_max and SUV_mean values of the metastatic lymph nodes were higher than those of the benign lymph nodes (5.77±2.66 vs. 2.79±1.29 and 3.16±1.28 vs. 1.78±1.01, respectively), and the difference was statistically significant (t=6.39, 5.96; both P<0.001). Furthermore, the ADC_min of metastatic lymph nodes was lower than that of benign lymph nodes (1.02±0.33 vs. 1.20±0.24), and the difference was statistically significant (t=−3.81, P<0.001). In comparison, there was no statistical significance in the comparison of ADC_mean (t=−1.52, P>0.05).

Conclusions The value of ¹⁸F-FDG PET/MRI in the preoperative T staging of patients with esophageal cancer is comparable to that of MRI, while its diagnostic performance for preoperative N staging of patients with esophageal cancer is better than MRI. Thus, it can be considered the preferred non-invasive preoperative staging method for patients with esophageal cancer.