Application Of Pancreas Perfusion CT Combined With Dual-energy CT In Diagnosis Of Functional Pancreatic Neuroendocrine Neoplasms

Part 1 The value of low-dose whole pancreas perfusion CT in diagnosis of functional pancreatic neuroendocrine neoplasmsObject:To evaluate the correlation between time to peak(TTP)of the functional pancreatic neuroendocrine neoplasms(F-PanNENs)and the density of the abdominal aorta,and to identify timing of individualized pancreatic phase.Material and Methods:18 patients with F-PanNENs,including 6 males and 12 females,with a mean age of 49.7±14.7(range,18-70),who underwent volume perfusion computed tomography(VPCT),were enrolled in this retrospective study.VPCT-Body was used to analyze perfusion data and the time to peak(TTP)of the F-PanNENs and normal pancreatic parenchyma.The perfusion data included blood flow(BF),blood volume(BV)and permeability(PMB).Dyn Eva was used to analyze the time when the abdominal aorta attained 100 Hounsfield units,HU(Tb100).All data were measured for three times,and the mean values were obtained for statistical analysis,to analyze the correlation between the TTP of F-PanNENs and Tbioo,as well as the correlation between TTP of F-PanNENs and normal pancreatic parenchyma.Dose-length-product(DLP)of the VPCT was recorded and theeffective dose(ED)was calculated.Results:The TTP of F-PanNENs was 25.94±4.54s(range,21-38s),the TTP of normal pancreatic parenchyma was 28.61 ± 4.47s(range,22-38s),and the difference between them was 2.67 ± 1.50s.The TTP was significantly shorter in F-PanNENs than in normal pancreatic parenchyma(P<0.01,t=7.57).The Tb100 was 16.72 ± 3.30s,significantly shorter than TTP of F-PanNENs(P<0.01,t=24.57),and strongly correlated with TTP of F-PanNENs(r=0.967).The difference between Tb100 and TTP of F-PanNENs was 9.22± 1.59s.The BF and BV in F-PanNENs(187.39 ± 76.93 mL/100mL/min,40.72 ± 23.32 mL/100mL,respectively)was significantly higher than normal pancreatic parenchyma(89.2 ±23.72mL/100mL/min,17.39 ± 10.24 mL/100mL,respectively).PMB was not significantly different between F-PanNENs(44.50 ± 43.28 mL/1 00mL/min)and normal pancreatic parenchyma(40.78 ± 17.95 mL/1 00mL/min)(P=0.718).The DLP of the VPCT was 386.2mGy*cm,resulting in an ED of 5.8 mSv.Conclusion:The TTP of F-PanNENs was strongly correlated with Tb100.Choosing 9s after Tb100 as the arterial phase,will improve significantly the detection of F-PanNENs,which was high perfusion in VPCT.Part 2 The value of individualized dual-energy enhanced CT in diagnosis of functional pancreatic neuroendocrine neoplasmsObject:To compare the detection and image quality in different post-processing of individualized dual-energy enhanced computed tomography(CT)in preoperative diagnosis of functional pancreatic neuroendocrine neoplasms(F-PanNENs).Materials and Methods:9 patients with F-PanNENs,including 3 males and 6 females,with a mean age of 50.9±15.9,who underwent individualized dual-energy enhanced CT,were enrolled in this retrospective study.Monoenergetic images from 40keV to 190keV in dual phase were reconstructed and the contrast noise ratio(CNR)of pancrease-to-tumor was calculated.The optimal monoenergetic image(Mono)with the highest CNRMono was recorded.Optimum contrast mixed images(OCM)in dual phase were reconstructed and the CNRocm was calculated.The CNRm of the weighted-average 120 kV images was recorded.All data were measured for three times,and the mean values were obtained for statistical analysis,to analyze the difference in CNRMono,CNRocm and CNRM.The detection of preoperative diagnosis of F-PanNENs in those images was compared.Results:CNRMono,CNRocm and CNRm in arterial phase was 4.89±1.60,3.37± 1.24,7.91 ±3.11,respectively.CNRocm was significantly larger than CNRMono,and CNRMono was significantly larger than CNRM.CNRMono,CNRocm and CNRM in venous phase was 2.13± 1.16,1.22±0.85,2.9± 1.92,respectively.And all of them were significantly smaller than CNR in arterial phase.Individualized arterial phase of dual-energy CT detected all of 9 tumors.In the venous phase images,the weighted-average 120 kV images detected 3 of 9 tumors,both the Mono and the OCM detected 4 of 9 tumors.Conclusion:Individualized dual-energy enhanced CT could obtain multi-pattens images in preoperative diagnosis of F-PanNENs,including 80kV images,Sn140kV images,weighted-average 120 kV images,monoenergetic images,and optimum contrast mixed images.The optimum contrast mixed images in individualized arterial phase of dual-energy CT had the highest CNR,which can improve the diagnostic sensitivity of F-PanNENs.