Dynamic CT of the liver

The most commonly used CT technique for contrast enhancement CE of the liver are dynamic CT scanning after either IV, direct hepatic arterial or indirect portal contrast injection. The need for these different approaches is because compromises have to be made which take into account the scanner performance, the pharmacodynamics of the available urographic contrast agent and the complex vascularisation of the liver and the tumors. Spiral scanning is a novel technique which allows to scan the entire liver in a single breathhold period of about 10 to 20 seconds with the a posteriori calculation of perfectly contiguous or even overlapping slices. These two new specifications offer entirely new perspectives in terms of liver enhancement. It becomes theoretically possible to scan the entire liver twice, during both the early arterial phase and the subsequent venous phase after one single short IV bolus injection. Hence the total amount of contrast media to be administered can be reduced while the diagnostic potential of the contrast agent is significantly increased.