| Pancreatic cancer is a malignant tumor of the digestive tract,and about 90% of it is ductal adenocarcinoma,which originates from the epithelium of the gland.The incidence and mortality of pancreatic cancer have increased in recent years,and it is one of the worst malignant tumors with the worst prognosis.Early diagnosis of pancreatic cancer is difficult due to the lack of typical clinical symptoms and laboratory indicators.Early diagnosis of pancreatic cancer mainly depends on imaging examination.CT and MRI are widely used in the detection and diagnosis of pancreatic cancer,but it relies mainly on visual observation,which is greatly influenced by subjective observer,and lack of quantitative indicators which can accurately reflect the lesions of small changes.DCE-MRI is to track the flow and distribution of gadolinium molecules in the capillaries and extracellular space by using MRI dynamic imaging,to reflect the tissue microvascular perfusion and the hemodynamic characteristics of microvascular infiltration.Early DCE-MRI studies have focused on brain tumors.With the development of MRI technology,the clinical study of DCE-MRI has been extended to the body and limbs,and breast cancer research is the most in-depth,including diagnosis and efficacy evaluation.DCE-MRI studies in pancreatic cancer mainly focus on diagnosis and differential diagnosis.Objective:To obtain effective parameters as imaging biomarkers of pancreatic cancer research for diagnosis and differential diagnosis,as well as parameters related to pathological classification,by analyzing DCE-MRI data of pancreatic lesions using hemodynamic software.Methods:From September 2013 to September 2015,55 patients with suspected pancreatic solid tumors(other imaging suggested)in our hospital were selected.They all underwent routine MRI and DCE-MRI.Each patient signed an informed consent for enhanced MRI examination.Among them,there were 6 cases of normal pancreas,36 cases of pancreatic cancer and 6 cases of pancreatic neuroendocrine tumor and 4 cases of inflammatory mass were pathologically confirmed,and 3 cases without pathological confirmation.DCE-MRI data were collected on 3.0-T MRI.Gadolinium contrast(Eunaige,GE,Ireland)was injected intravenously with a high pressure syringe,at a rate of 0.15 mmol/kg(0.3 ml/kg),at a speed of 2 ml/s,and followed by 20 ml saline at the same rate.The collected data were transmitted to a computer equipped with hemodynamic software(Omni-Kinetics)for data analysis and multiple quantitative parameter measurements.AIF and area of interest are selected by experienced radiologists.The parameters include: Ktrans,Kep,Ve,Vp and AUC.CT enhancement image data of 36 patients with pancreatic cancer were retrospectively analyzed and its enhancement forms were summarized.Quantitative parameters of head,body and tail of normal pancreas were measured and compared.Quantitative parameters of pancreatic cancer and its caudal side normal pancreatic tissue were measured and compared.Quantitative parameters of pancreatic cancer and its cephalic normal pancreatic tissue were measured and compared.The parameters of pancreatic tissue on the caudal side and pancreatic tissue on the cephalic side were compared.Quantitative parameters of neuroendocrine tumor and chronic inflammatory mass were measured,and quantitative parameters of the normal pancreas,pancreatic cancer,neuroendocrine tumor and chronic inflammatory mass were compared,and time –relative enhancement curve were drawed.According to the pathological grade of pancreatic ductal adenocarcinoma,the patients were divided into three groups: low differentiation group,middle differentiation group and high differentiation group.The quantitative parameters of the three groups were measured separately and the correlation analysis was conducted with the pathological grade.The correlation between CT enhancement and pathological grade was analyzed.Results:Quantitative parameters Ktrans,Kep,Ve,Vp and AUC showed no statistical difference in the head,body and tail of normal pancreas(P > 0.05).Ktrans,Kep and Ve were different in pancreatic cancer and the relative normal pancreatic tissue on the caudal and cephalic side(P<0.05).Ktrans on the caudal side of pancreatic carcinoma were different from that in the cephalic side(P<0.05).Ktrans were significantly different in pancreatic cancer,neuroendocrine tumor,chronic inflammation and normal pancreas(P<0.001);Kep and Ve were different in pancreatic cancer,neuroendocrine tumor,chronic inflammation and normal pancreas(P<0.05).Quantitative parameter Ktrans showed statistically significant differences in pancreatic cancer,compared to normal pancreas,neuroendocrine tumor and chronic inflammatory mass separately(P< 0.001,P<0.001,P<0.001).There were significant differences in Kep between pancreatic cancer and normal pancreatic,pancreatic and neuroendocrine tumors(P= 0.001,P<0.001).There were significant differences in Ve between pancreatic cancer and normal pancreas,and between pancreatic cancer and neuroendocrine tumor(P<0.001,P<0.05).The time –relative enhancement curve of normal pancreas was 100% Type A.The curve of pancreatic cancer was Type A(8.3%),Type B(72.2%),Type C(16.7%)and Type D(2.8%).The curve of neuroendocrine tumor was Type A(36.3%),Type B(18.2%),and Type D(45.5%).The curce of chronic inflammatory mass was Type C(75%)and Type D(25%).Quantitative parameters Ktrans showed differences in different pathological grades of pancreatic cancer(P<0.05).Quantitative parameter Ktrans showed differences between low and high differentiaed groups,middle and high differentiated groups(P<0.05).The pathological grade showed a moderate positive correlation with the quantitative parameter Ktrans of DCE-MRI(r =0.666,P<0.001).The pathological grade was negatively correlated with the CT enhancement forms(r =-0.587,P<0.001).Conclusion:This study confirmed the the role of Ktrans,Kep and Ve in the diagnosis and differential diagnosis of pancreatic cancer;Quantitative parameters Ktrans had correlation with pathological classification compared with CT enhancement;which explained the DCE-MRI is a reliable quantitative imaging method,and had positive significance to the clinical diagnosis of pancreatic cancer,Quantitative parameter Ktrans can be used as an imaging biomarker for pancreatic cancer research. |
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