The Evaluation Of PET/MRI In Pretreatment Staging Of Gastric Cancer

Background and Aims An accurate clinical tumor staging before surgery is critical for the benefits of patients with gastric cancer.CT remains the first choice for pretreatment staging in GC,however,the limited studies has showed that MRI has a superior performance in GC staging compared with CT.Both of them have a worse performance in diagnosis of distant metastasis lesions than PET/CT.Due to the advantages of superior softer-tissue contrast and functional imaging,18F-FDG PET/MRI has been applied to the diagnosis and preoperative staging in the majority solid tumor types;however,the report that PET/MRI applied in gastric cancer was rare because of motion artifacts.We investigated the value of PET/MRI for preoperative staging compared with PET/CT in gastric cancer(GC).Methods Thirty patients with confirmed GC were recruited from the Chinese XX General Hospital,between December 2016 and November 2017.Each patient underwent PET/CT and PET/MRI.TNM staging for each patient was determined from the PET/MRI and PET/CT images.The diagnostic performance of PET/MRI and PET/CT was calculated compared with the pathologic TNM stage.The two methods were compared using statistical analyses.Results The accuracy for T staging between PET/MRI and.PET/CT was 76.9%vs.57.7%.Any statistically significant difference was found in the comparisons of T staging.In T1 staging,the sensitivity and accuracy for PET/MRI vs.PET/CT was 1.0 vs.0.6 and 1.0 vs 0,88,respectively.The area under the curve(AUC)for PET/MRI vs.PET/CT was 1.00 vs.0.78 in T1 stage,0.73 vs.0.66 in T2 stage,0.72 vs.0.57 in T3 stage and 0.86 vs.0.83 in T4 stage.In T2 staging,PET/MRI has a superior performance than PET/CT,the sensitivity and accuracy were 95%vs.82%and 88%vs.77%.The sensitivity of T3 stage in PET/MRI was 0.5 and PET/CT was 0.25.In T4 staging,PET/MRI correctly diagnosis all patients and the accuracy was 0.89.The sensitivity of PET/CT was 0.89 and the accuracy was 0.77.The accuracy for N staging of PET/MRI vs.PET/CT was 53.9%vs.34.0%,and for N0 vs.N+ was 85.0%vs.77.0%.The sensitivity for PET/MRI in N3 staging was 0.67 and 0 for PET/CT.There was a statistically significant difference in the AUC for N1 staging(PET/MRI vs.PET/CT,0.63 vs.0.53,p=0.03).There exists a negative relation between SUV value and ADC value.The SUVmax/ADCmax positively correlate with tumor volume and Ki-67(r=0.663,p=0.001;r=0.690,p=0.000).Conclusion PET/MRI performs more accurately in TN staging compared with PET/CT and is optimal for accurate N staging.SUVmax/ADC have positive correlations with tumor volume and Ki-67 and may have a potential value in early prediction of neoadjuvant therapy.