| Part One: Dynamic Enhanced MR Imaging of Pancreas---The Study of Scanning Time Window Purpose: To make up the time versus gadolinium-enhancement index curves of the normal pancreas, to investigate the best multiphase scanning time window. Materials and Methods: 60 patients without any pancreatic diseases were randomly assigned to A,B,C group. Contrast test-bolus imaging with turbo-FLASH was performed to determine the transit time (TwA) from elbow vein to abdominal aorta in all patients. Gadolinium was used with the same amounts, injection speed and saline solution in three groups. According to the formula: D=TV-A-1/4TA+t, the first-phase scanning time after administration of Gd-DTPA was definite at t=0,5,10 seconds respective to A, B,C group. The second-phase and third-phase scanning in A group were respectively delayed 10 seconds after the end of former scanning. In B and C group, the second-phase scanning was respectively delayed lOs after the end of the first phase; the third phase scanning was delayed 30s after the end of the second phase. Signal intensities of pancreas, liver, and peripancreatic vessels were measured and enhancement index was calculated and using a five-point scale assessed images quality. Results: The transit time from elbow vein to abdominal aorta ranged widely from 9 to 29 seconds after injecting Gd-DTPA and it increasingly became delayed with aging above forty year old. The best pancreatic enhancement occurred at the first-phase of B group (a delay of 5 seconds after arrival of Gd-DTPA to the abdominal aorta). The contrast-enhanced index of pancreas was 18.6, which evidently higher than A group (10.4, p |
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