Title: Spiral CT portography: correlation with different injection rate
Abstract: Objective To choose optimal injection rate in spiral CT portography(CTP) by comparing 3D CTP images using different injection rates. Methods Thirty seven patients were randomly divided into 2 groups (11 and 26 cases in each group). Single level dynamic scan was completed at the first liver hilus, starting at 15 s or 30 s after initial contrast injection(2 ml/kg) with injection rate 1.5 ml/s (slow group) or 3.0 ml/s (rapid group). The continuous scan were repeated every 5 s for 120 s or 135 s. ROI was used to measure the CT value of the portal vein and the liver parenchyma, respectively, and then the time density curves were drawn. Spiral CT portography were performed at injection rate of 1.5 ml/s or 3.0 ml/s as the delay time designed described above, including 98 cases in rapid group and 12 cases in slow group. Both MPVR (multi projection volume reconstruction) and MIP (maximum intensity projection) were employed for reconstruction. All images were ranked according to the grade of portal vein, the different CT value between the portal vein and the liver parenchyma, the edge′s definition of blood vessel, the grade of hepatic vein and the display of IVC by 2 radiologists. Results The maximum density difference in average between the portal vein and the liver parenchyma was 53.4 HU and 83.9 HU, respectively ( t =16.418, P 0.001) in slow group and rapid one, and the mean reaching time was 80 s and 60 s, respectively ( t =13.394, P 0.001). In slow injection group, the average score of MPVR image was 9.3, while it was 12.5 ( t =3.514, P 0.01) in rapid injection group. Rapid group was better than slow one at the PV L, the grade of the portal vein, and the edge′s definition of blood vessel. Conclusion Using rapid injection rate (3.0 ml/s), the maximum density difference between the portal vein and the liver parenchyma increases, and the mean reaching time shortens. The quality of 3D CTP image of rapid injection rate (3.0 ml/s) is superior to that of slow injection rate (1.5 ml/s).
Publication Year: 2000
Publication Date: 2000-01-01
Language: en
Type: article
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