| Objective To investigate the optimal single-phase scan enhanced delay time of MSCT, and the diagnostic value in suspected pancreas carcinoma examination.Methods (1) Total 60 cases meeting the including and excluding criteria underwent enhanced serial dynamic CT scanning of the pancreas. By means of injection dosage of 120ml contrast at 2.5ml/s rate, CT value of the peripancreatic aorta and portal vein, pancreatic and hepatic parenchyma was measured respectively in order to make the time-density curves of their enhancement. (2) Incremental pancreatic multi-phase MSCT were performed in 20 cases meeting the including and excluding criteria with the same dosage of contrast and injection rate. Reconstruction of peripancreatic vessels was performed with multiplanar reconstruction (MPR) and surface shaded display (SSD).The display rate and degree of peripancreatic blood vessels at 40s and 60s were evaluated emphatically. (3) From April 2006 to February 2007, 25 cases who were suspected pancreatic carcinoma were performed by Single-phase and Two-phase Enhanced Helical CT. Single-phase and Two-phase began at 60 seconds and 40,80 seconds after the start of the injection. Finaly 17 cases were confirmed pancreatic carcinoma by imaging findings.Mean CT attenuation values of normal pancreas, tumor and tumor-pancreas contrast for both phases were obtained and the differences were calculated.The images were analyzed separately by two radiologists , and the results were tested statistically.Results (1) The results of enhanced serial dynamic CT scanning indicated that the time was 50s for peak enhancement of the peripancreatic aorta, while mean value of their enhancement was (295.75±40.13) HU. 60s for the peripancreatic portal vein, while mean value of their enhancement was (180.37±25.34) HU. 60s for the pancreatic parenchyma(the platform stage for the pancreatic parenchyma ranged from 60s to 70s), while mean value of their enhancement was (123.34±20.37) HU, and 60s for the hepatic parenchyma (the platform stage for the hepatic parenchyma ranged from 60s to 80s), while mean value of their enhancement was (108.79±19.35) HU. (2) The results of step two showed that the display rate was 100% for the peripancreatic blood vessels at 40s and 60s .While for the displaying degree of peripancreatic blood vessels, 60s was well superior to 40s. (3) All the pancreatic carcinoma and its surrounding vessels invaded were delineated in Single-phase and Two-phase images.Conclusion (1)The optimal single-phase enhancement scan protocol of MSCT in suspected pancreas carcinoma examination was the injection dosage of 120ml contrast at 2.5ml/s rate and the recommended delay time was 60s. (2) Single-phase enhanced helical CT has the higher value in diagnosing pancreatic adenocarcinoma, and also could meet the requirement of diagnosis.
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