The Value Of High Field Magnetic Resonance Imaging In The Preoperative T Staging Of Gastric Carcinoma And Grading

Background and PurposeGastric cancer is one of the upper digestive tract malignant tumors of the most common, the incidence and mortality rates are very high, and the prognosis is poor, ranking No. 2 in cancer-related death in the 5-year survival rate is only 20% ~ 30% [1]. Gastric cancer incidence and mortality due to geographical differences and different, despite the decline in recent years, GC is still the second leading cause of cancer-related deaths in the world. Stomach cancer treatment methods are surgery, chemotherapy, preoperative and postoperative discharge method, of which surgery is considered the only curative treatment of gastric cancer, but only a small number of patients at the time of diagnosis can be surgically removed. Tumor- node- metastasis(TNM) staging system, which is an accepted staging system in clinical practice, it has been shown to accurately predict the prognosis of patients [2]. Therefore, based on the early diagnosis of gastric cancer TNM staging and accurate staging will help clinicians develop the right treatment plan, thus improving the prognosis of patients. Endoscopy, EUS and CT has been widely used before the diagnosis and preoperativestaging of gastric cancer, but EUS is an invasive method, and its diagnostic results for the operator dependence great, but CT presence of ionizing radiation. In recent years, MR imaging techniques develop rapidly, advantages that show soft tissue much clearer than two means combined with excellent soft tissue contrast, noninvasive functional imaging and non-ionizing radiation. In addition, recent development of MRI, causing increased spatial and temporal resolution as well as to reduce motion artifacts [3]. Therefore, in recent years the use of MRI for gastric cancer diagnosis and preoperative staging before becoming one of the hotspots. This study was aimed to explore:1.Observed gastric MRI findings, evaluate the value of preoperative staging of gastric different sequences of high-field MRI;2.Investigate the single and double exponential value of DWI in the differential diagnosis of gastric lesions and gastric preoperative grading.Materials and MethodsCase of GE Discovery750 3.0T MR scanner, 8-channel phased-array body coil, 35 patients with suspected gastric prospective study, another 10 cases were randomly selected healthy people observe normal stomach, the patient is asked to keep fasting and being checked before checking 10 min intramuscular 654-2 20 mg, drink warm water before checking 5min 500ml-1000 m L.Conventional scan sequence using coronal breath single shot fast spin-echo(T2WI / TSE) and axial fat-suppressed respiratory triggered; fast spoiled gradient echo sequence pairs(FSPGR-dual echo).DWI(diffusion-weighted imaging, DWI): Traditional DWI sequence selected b = 0,1000 s / mm2; multi-b-value DWI sequence: Selection b value = 0,20,50,100,200,400,600,800,1000,1200 s / mm2, respectively, and their adjacent normal gastric parietal get the ADC map, D map, D * map, f, and measure three times averaged, and compare. DCE-MRI: the use of axial acceleration volume collection liver(liver acceleration volume acquisition, LAVA) sequence.All data use SPSS17.0 software package for processing.Result1.In vivo MRI examination, the appropriate filling of the stomach can be displayed 1-3 layer structure; MRI multi-directional scanning and 3D reconstruction, can accurately display the stomach tumor location and size, shape. 2.MRI conventional sequences, MRI conventional sequence + DWI, MRI conventional sequence + DWI + DCE-MRI three methods for T staging and pathological findings accuracy rates were 68.6%, 74.3%, 91.4%. 3.gastric cancer ADC, D, D *, f mean respectively(1.43 ± 0.25) × 10-3mm2 / s,(0.96 ± 0.32) ×10-3mm2 / s,(16.15 ± 11.65) ×10-3mm2 / s,(52.26 ± 14.83)%; control group ADC, D, D *, f mean respectively(2.83 ± 0.47) ×10-3mm2 / s,(2.33 ± 0.49) ×10-3mm2 / s,(22.16 ± 10.82) ×10-3mm2 / s,(34.41 ± 14.49)%. ADC values of gastric cancer, D values, D * value is less than the control group, and f is greater than in the control group, ADC, D, f differences were statistically significant; and D * value of the difference was not statistically significant. 4.Poorly differentiated group of gastric cancer group ADC, D, D *, f mean respectively(1.27 ± 0.19) ×10-3mm2 / s,(0.76 ± 0.16) ×10-3mm2 / s,(16.54 ± 8.28) ×10-3mm2 / s,(57.92 ± 13.13)%, well-differentiated group ADC, D, D *, f mean respectively(1.61 ± 0.18) ×10-3mm2 / s,(1.12 ± 0.31) ×10-3mm2 / s,(18.24 ± 13.45) ×10-3mm2 / s,(45.75 ± 14.41)%, poorly differentiated gastric cancer group ADC value, D value, D * value of less than well-differentiated group, and f is greater than the well differentiated group, ADC, D, f differences were statistically significant; and D * value difference was not statistically significant.Conclusion1.MRI + DWI conventional sequence of T staging of gastric cancer have limited value. 2.DWI scans valuable qualitative diagnosis of gastric cancer, but did not significantly improve the preoperative T staging of gastric accuracy.3.MRI conventional sequence + DWI + DCE has high consistency comparing with the pathology in T staging of gastric cancer,and the sequences are the best combination of the current T staging of gastric cancer. 4.ADC as single-exponential model parameters and IVIM-DWI parameter values D, f value are helpful for the identification of gastric cancer and adjacent normal stomach. 5.There is some help in ADC as single-exponential model parameter and IVIM-DWI parameter values D, f value for the differential diagnosis of gastric level of differentiation.