Lower energy levels and iodine-based material decomposition images increase pancreatic ductal adenocarcinoma conspicuity on rapid kV-switching dual-energy CT

Abstract

PurposeMultidetector computed tomography (MDCT) is used in the diagnosis of pancreatic ductal adenocarcinoma (PDAC), but it may be inadequate in some cases. Tumor detection can be improved using rapid kV-switching dual-energy CT (rsDECT) and iodine maps. Our aim this study is to evaluate tumor conspicuity in PDAC cases using rsDECT and iodine maps.MethodsNinety cases with PDAC were evaluated rsDECT. Tumor contrast (HU) differences, tumor size, CNR (contrast-noise ratio), and noise were measured at 70keV, individual CNR-energy level, and 45keV, respectively. Quantitative differences in contrast gain 70-CNR and CNR-45 were compared. On iodine maps, the iodine concentration measured in the tumor and parenchyma was normalized to the aorta as normalized iodine concentration (NIC) and compared.ResultsThe median optimized viewing energy level was 51keV. The meanSD tumor contrast values were 62 +/- 20, 115 +/- 48, and 152 +/- 48 HU (p<0.001); the largest axial diameters were 36.6 +/- 5.1, 37.9 +/- 4.2, and 38.3 +/- 3.7mm (p=0.015); the CNRs were 1.83 +/- 0.72, 3.37 +/- 0.93, and 2.36 +/- 0.56; and the image noise levels were 23.7 +/- 6.8, 39.3 +/- 11.6, and 59.5 +/- 17.2 (p<0.001) (p<0.001) for 70keV, optimized energy level, and 45keV, respectively. The mean +/- SD contrast gain 70-CNR was 63 +/- 12; and CNR-45 was 31 +/- 26 HU (p<0.001). NICtumor and NICparenchyma values were 0.62 +/- 0.03 and 1.36 +/- 0.05mg/mL, respectively (p=0.004).Conclusion The use of low energy levels on rsDECT and iodine maps improves tumor conspicuity. This situation may be help better detection of pancreatic tumors.