Background: Many previous studies have analyzed and proposed different strategies to achieve optimal contrast timing and enhancement in the late arterial phase to best depict arterialized lesions in the liver and hypoattenuating tumors in the pancreas(1-12). But even with the use of state-of-the-art protocols, inter-subject variations of optimal contrast enhancement in liver lesions and pancreas parenchyma are still very common. The aim of this study is to first analyze these alterations and to, secondly, use the newly gained knowledge to design a dose-neutral multiple arterial phase protocol. An optimized arterial phase protocol might improve the detection of hepatocellular carcinoma (HCC) and/or pancreatic adenocarcinoma.~Purpose: To measure when the greatest difference in attenuation occurs in HCC compared to background liver parenchyma resp. in pancreatic lesions vs. pancreatic parenchyma. To describe the inter-subject variation of these enhancement times and to evaluate at which time-points an optimal late arterial phase can be achieved. The investigators will use the perfusion scanning technique, bolus-tracking and high body-weight-adjusted volumes of contrast media (CM).~Anticipated results: The aim is to find the best time points for optimal CM-enhancement in HCC lesions and pancreas parenchyma. The results will show the extent of the inter-subject temporal enhancement differences and will be used to design an optimized late arterial phase protocol for clinical practice and future studies.
To examine inter-subject variations of optimal late arterial phase contrast-enhancement defined as the greatest difference in contrast attenuation of hepatocellular carcinoma (HCC) compared to background liver parenchyma resp. pancreatic lesions compared to pancreatic parenchyma. To evaluate which time-points best depict an optimal late arterial phase.