The Value Of Spectral CT Combined With Perfusion Scan In Pancreatic Neuroendocrine Tumors

Objective:To explore the diagnostic value of spectral CT combined with perfusion scanning in pancreatic neuroendocrine tumors and to evaluate the differences in perfusion parameters of low levels pancreatic neuroendocrine tumors.Materials and methods:From December 2017 to October 2019,in the First Affiliated Hospital of Zhengzhou University,50 patients who underwent one-stop spectral CT combined perfusion scan for clinically suspected pancreatic neuroendocrine tumors were prospectively enrolled in this study.There were 36 patients with neuroendocrine tumors,including 15 males and 21 females,ranging in age from 20 to 70 years,with a median age of 52 years.The scannings were performed on a GE Revolution CT scan machine.After a conventional upper abdomen scan,the entire pancreas was scanned with low-dose perfusion combined with spectroscopy.After the scan was completed,the perfusion and spectral images were reconstructed and data were measured.Imaging characteristics were analyed,According to the perfusion pseudocolor map,the perfusion parameters,such as BV,BF,PS,MTT,TTP,Tmax,MSI,IRF T0,between the tumor and the normal pancreas parenchyma were compared.The difference perfusion parameters between different levela of tumor were analyed.The differences in spectrum parameters between tumor and normal parenchyma were compared,including 60 keV-140 keV single energy CT values(at 10 keV intervals)?arteriovenous phase iodine concentration(IC),arteriovenous phase water concentration(WC),and calculation of lesion Compared with the standard iodine concentration(NIC)of the parenchymal arteriovenous phase of normal pancreas;the radiation dose was analyzed.Results:?In different scanning modes,the detection rate of lesions is different.The detection rate of spectral CT combined with perfusion is 90.3%? 96.3%,and the detection rate of conventional pancreatic perfusion is 82.8(p<0,05).Arterial phase energy spectrum combined with perfusion scan is more conducive to the detection of lesions.?The pancreatic neuroendocrine tumor has a rich blood supplement.Perfusion results show that the tumor is significantly more perfused than the adjacent normal parenchyma.The perfusion parameters BF,BV,and MSI of the pNETs lesions are 238.24±133.58 ml/min-1·100g-1,22.67 ± 6.54 ml/100g,10.60±3.37,which are higher than normal parenchymal parameters,and the difference is statistically meaningful(p<0.05,both);and the paraneters MTT,PS,TTP,and Tmax are 6.98 ±3.52 s,3.28 ± 1.79 ml/min-1·100g-1,16.±2.37 s,4.11±1.78 s,which were lower than the normal parenchymal parameters,and the difference was statistically meaningful(p<0.05,both);the IRF T0 parameter was not statistically different between tumor and normal parenchymal.?pNETs tumors are divided into two groups according to different pathological levels,that is,compared with group G1 and group G2.The BF and IRF T0 of the perfusion parameters between the two groups were 224.72±77.95ml/min-1·100g-1,0.66 ± 0.10,287.63 ± 89.07 ml/min-1·100g-1,1.56±0.25,the difference is statistically meaningful(p<0.05,both);the higher the level,the higher blood flow.?In the arterial phase the CT value of single-energy keV between pNETs lesions and the normal pancreatic parenchyma group is different.Under the same single energy,the CT value of the lesion is higher than that of the pancreatic parenchyma,and there is no significant difference in CT value between the two group.?The IC value,WC value,and NIC value of arterial lesions were 82.31±33.71 ug/cm3,1070.71±72.32 mg/cm3,and 0.76±0.50 ug/cm3,which were higher than those of normal pancreas parenchyma,and the differences were statistically significant;IC value and NIC value of venous lesions were 37.26 ±26.28 ug/cm3 and 0.78 ± 0.20 ug/cm3,which were higher than normal parenchyma(p<0.05);the spectrum curve of arterial show that tumors'curve was higher than normal parenchyma's,The lower single energ keV,the greater difference in the CT values between tumor and normal parenchyma,and the tumor was seen more easier.?The effective radiation dose received by the patient during the whole process of CT and perfusion scan was 19.24 ± 3.21 mSv.Conclusions:Spectral CT combined with perfusion imaging is conducive to the detection of pancreatic neuroendocrine tumor lesions,the detection rate is higher than conventional pancreatic perfusion,and the effective radiation dose is slightly lower than it.At the same time,the lesion can be distinguished from normal parenchyma based on perfusion parameters and spectral parameters.The classification of pancreatic neuroendocrine tumors can be predicted based on BF and IRF T0 perfusion parameters,which has certain significance for guiding clinical diagnosis and treatment.