Multi-detector row helical CT of the pancreas: Effect of contrast-enhancedmultiphasic imaging on enhancement af the pancreas, peripancreatic vasculature, and pancreatic adenocarcinoma

PURPOSE: To determine the optimal phase for enhancement of the normal pancr eas and peripancreatic vasculature and the maximal tumor-to-pancreatic pare nchymal enhancement difference by using multiphase, contrast material-enhan ced, multi-detector row helical computed tomography (CT). MATERIALS AND METHODS: Forty-nine patients with a normal-appearing pancreas but suspected of having pancreatic abnormality and 28 patients with proved pancreatic adenocarcinoma underwent multiphase, contrast-enhanced, multi-d etector row CT during the arterial phase (AP), pancreatic parenchymal phase (PPP)I and portal venous phase (PVP). Attenuation values of the normal pan creas, pancreatic adenocarcinoma, celiac and superior mesenteric arteries, and superior mesenteric and portal veins were measured during all three ima ging phases. Quantitative analysis of these measurements and subjective qua litative analysis of tumor conspicuity were performed. RESULTS: Maximal enhancement of the normal pancreatic parenchyma occurred d uring the PPP. Maximal tumor-to-parenchyma attenuation differences during t he PPP and PVP were equivalent but greater than that during the AP. Subject ive analysis revealed that tumor conspicuity during the PPP and PVP was equ ivalent but superior to that during the AP. Maximal arterial enhancement wa s seen during the PPP, and maximal venous enhancement was seen during the P VP. CONCLUSION: A combination of PPP and PVP imaging is sufficient for detectio n of pancreatic adenocarcinoma, because it provides maximal pancreatic pare nchymal and peripancreatic vascular enhancement. AP imaging can be reserved for patients in whom CT angiography is required.