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

Purpose

Multidetector 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.

Methods

Ninety cases with PDAC were evaluated rsDECT. Tumor contrast (HU) differences, tumor size, CNR (contrast-noise ratio), and noise were measured at 70 keV, individual CNR-energy level, and 45 keV, 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.

Results

The median optimized viewing energy level was 51 keV. The mean ± SD 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 ± 3.7 mm (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 70 keV, optimized energy level, and 45 keV, respectively. The mean ± SD contrast gain ∆70-CNR was 63 ± 12; and ∆CNR-45 was 31 ± 26 HU (p < 0.001). NIC_tumor and NIC_parenchyma values were 0.62 ± 0.03 and 1.36 ± 0.05 mg/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.