Dual-phase spiral CT: technique and clinical value for pancreatic carcinoma

Objective: To study the protocols of dual-phase spiral CT for the evaluation of pancreatic carcinoma. Methods: One hundred and four patients (44 with pancreatic carcinoma, 60 with no upper abdominal disease) underwent dual-phase spiral CT. In group A, 40 patients were scanned for arterial and portal phase (20 and 60 s after intravenous infusion of contrast material at 3 ml/s). In group B, 64 patients were scanned for pancreatic and hepatic phase (35 and 70 s). Mean CT attenuation value was obtained for normal pancreatic parenchyma, lesions and major peri-pancreatic blood vessels, respectively. The display rate of the small peri-pancreatic veins was calculated in the pancreatic and hepatic phase. All data were statistically analyzed. Results: In normal group, enhancement value of pancreas during the pancreatic phase was the greatest of all phases [(118.10 +-17.78) HU, P<0.05]. Major per-pancreatic vascular structures were visualized well in the pancreatic phase. The display rate of the small peri-pancreatic veins was higher in the pancreatic phase than in the hepatic phase (P<0.05). In abnormal group, the tumor-to-pancreas contrast difference was also the greatest during the pancreatic phase [(65.89 +- 28.81) HU, P<0.05]. Four cases of small cancer were found. It was identified that 54% of unresectable cases with major peri-pancreatic vessels invasion, 42% with small peri-pancreatic veins dilation, and 37% with metastatic hepatic neoplasms. Conclusion: In the dual-phase spiral CT protocol for pancreas, pancreatic and hepatic phase could be an optimal selection. It had an important value in diagnosing pancreatic carcinoma