Evaluation of pancreatic iodine uptake and related influential factors in multiphase dual-energy CT.

ABSTRACT

OBJECTIVES: To establish normative values and identify potential factors influencing pancreatic iodine uptake using dual-energy CT (DECT). MATERIALS AND METHODS: This retrospective study included participants without pancreatic diseases undergoing DECT at two institutions with different platforms. Their protocols both included arterial phase (AP), portal venous phase (PP), and equilibrium phase (EP), defined as 35 s-40 s, 60 s-70 s, and 150 s-180 s after injection of contrast agent, respectively. Both iodine concentration (IC) and normalised IC (NIC) were measured. Demographic features, local measurements of the pancreas and visceral fat area (VFA) were considered as potential factors influencing iodine uptake using multivariate linear regression analyses. RESULTS: A total of 562 participants (median age 58 years [interquartile range 47-67], with 282 men) were evaluated. The mean IC differed significantly between two institutions (all p < 0.001) across three contrast-enhanced phases, while the mean NIC showed no significant differences (all p > 0.05). The mean values of NIC were 0.22 at AP, 0.43 at PP and 0.45 at EP. NICAP was independently affected by VFA (ß = 0.362, p < 0.001), smoking (ß = -0.240, p = 0.001), and type-II diabetes (ß = -0.449, p < 0.001); NICPP by VFA (ß = -0.301, p = 0.017) and smoking (ß = -0.291, p < 0.001); and NICEP by smoking (ß = -0.154, p = 0.10) and alcohol consumption (ß = -0.350, p < 0.001) with statistical power values over 0.81. CONCLUSION: NIC values were consistent across institutions. Abdominal obesity, smoking, alcohol consumption, and diabetes are independent factors influencing pancreatic iodine uptake. CLINICAL RELEVANCE STATEMENT This study has provided reference normative values, influential factors and effective normalisation methods of pancreatic iodine uptake in multiphase dual-energy CT for future studies in this area as a new biological marker. KEY POINTS Evaluation of pancreatic iodine uptake measured by dual-energy CT is a promising method for future studies. Abdominal obesity, smoking, alcohol consumption, diabetes, and sex are independent factors influencing pancreatic iodine uptake. Utility of normalised iodine concentration is necessary to ensure the consistency across different institutions.