The Clinical Role Of 2nd Generation DSCT Dual-Energy Multiple Image Technique In Diagnosis Of Pancreatic Adenocarcinoma

Objective:To explore the clinical role of second generation dual-source CT dual-engergy multiple image technique in diagnosis of pancreatic adenocarcinoma.Methods:Thirty-three patients with pancreatic carcinoma proved by surgical pathology underwent abdominal dual-phase enhancement scans by second generation dual-source CT with dual-engergy technique.All the data were analyzed with dual energy software to get virtual no contrast image、liner blend image、non-liner blend image、iodine map、the spectral curves、the highest CNR value photon energy image and 70kev photon energy image.The average CT value,focus region noise(SD),signal-noise ratio(SNR)of pancreatic carcinoma tissue,score of subjective imaging quality and the detection sensitivity of pancreatic carcinoma were compared between TNC and VNC;the absolute enhancement value of pancreatic carcinoma tissue(AEV),the relative enhancement value of pancreatic carcinoma tissue(REV),enhancement ratio(ER)of carcinoma tissue to pancreatic parenchyma,and the image contrast to noise ratio(CNR)of liner blend image、non-liner blend image and iodine map were analysed;the cure slope were compared among pancreatic carcinoma tissue,parenchyma and psoas major;and the imaging CNR was compared between the highest CNR value photon energy image and 70 kev photon energy image.Results:The CT value of VNC in pancreatic carcinoma tissue was positively correlated with that of TNC.There were significant differences in CT value,SD and SNR of lesion between TNC and VNC(P<0.05),SD was VNC<TNC and SNR was VNC>TNC.There was no significant difference in subjective imaging quality scores and the detection sensitivity of pancreatic carcinoma between TNC and VNC(P>0.05).On arterial phase,there was statistical difference in AEV,REV and CNR value among liner blend image,non-liner blend image and iodine map(P<0.05).On parenchymal phase,there was significant difference in REV,ER,and CNR value among the three groups(P<0.01).Between arterial and parenchymal phase,three sequences were compared one-to-one,there was statistically significant difference in AEV and REV value of carcinoma tissues among the groups(P<0.05).There was statistically significant difference in linear blend image of ER value and iodine map of CNR in dual phase enhancement(P<0.05).The curve slope of pancreatic carcinoma tissue,normal pancreatic parenchyma and psoas major respectively was 0.769,1.451 and 0.357 in arterial phase,and that was 1.076,1.502 and 0.603 in parenchymal phase.There was significant difference among pancreatic carcinoma tissue,normal pancreatic parenchyma and psoas major in arterial phase and parenchymal phase(P<0.05).Between arterial and parenchymal phase,there was statistically significant difference in pancreatic carcinoma tissue and psoas major(P<0.05).There was no statistically significant difference between the highest CNR value photon energy image and 70kev photon energy image in CNR on the same phase(P>0.05).However between arterial and parenchymal phase,there was significant difference in the highest CNR value photon energy image and 70kev photon energy image of CNR(P<0.05),and that of arterial phase>that of parenchymal phase.Conclusions:1.Imaging quality of VNCT derived from dual-energy CT enhancing scan is similar to TNCT,and can meet the diagnostic requirements.2.Dual-energy CT in dual Phase enhanced scan mode combined with multiple sequences can be used to optimally display pancreatic carcinoma lesions.3.The spctrum curve of spectral CT can be used to the semiquantitative analysis of attenuation characteristic of pancreatic carcinoma.Spectral CT imaging have potential auxiliary for diagnosis of pancreatic adenocarcinoma.