Value of CT spectral imaging in demonstration of pancreatic ductal adenocarcinoma / 实用放射学杂志

ABSTRACT

Objective To explore the value of CT spectral imaging in the demonstration of pancreatic ductal adenocarcinoma (PDAC).Methods 113 patients were scanned by CT spectral,and gemstone spectral imaging (GSI) was performed in late arterial phase (AP) and portal venous phase (PP).All diagnosis were pathologically confirmed.The ROIs were placed on the lesion and on the pancreatic parenchyma.The ROI files including the CTmono values and the normalized CTmono values (normalized to pancreatic parenchyma) were saved.The works were performed three times repeatedly.CNR values ranged from 40 keV to 140 keV and the optimal keV in AP and PP were calculated.The differences of CTmono values, normalized CTmono values,and CNR were compared between the optimal keV and 70 keV(equivalent to conventional 120 kVp energy level).Paired t-test and Wilcoxon signed rank test were performed.P<0.05 was considered statistically significant.Results The optimal monochromatic energy of PDAC were 40 keV in both AP and PP.The optimal CNR values(mean±standard) were 2.31±1.02 and 2.38±1.02 in AP and PP,while the corresponding values of 70 keV were 2.08±0.98 and 2.12±0.96.The CNR of 40 keV was higher than that of 70 keV in both AP and PP.The CTmono values of PDAC were (58±13) HU and (71±19) HU at 70 keV and were (111±44) HU and (155±57) HU at 40 keV in AP and PP.The CTmono value in PP was higher than in AP.The median of normalized CTmono values of PDAC at 40 keV were 47.0% and 53.9% in AP and PP, and were lower than those of 70 keV,which were 57.7% and 61.8%.The differences of normalized CTmono values between 40 keV and 70 keV were significant.Conclusion CT spectral imaging manifests that PDAC is hypovascular both in AP and PP and is progressively enhanced form AP to PP.There is maximal conspicuity of tumor in AP, and the optimal monochromatic imaging can improve the conspicuity of PDAC lesion.