Arterial phase CT-imaging is crucial for detecting hypervascular liver lesions, for example hepatocellular carcinoma. When the tube voltage, which used to be fixed at 120 kV, will be lowered, the CT value of iodine will become higher. Therefore, arterial enhancing lesions are more conspicuous at low kV arterial phase CT (1).However, when lowering the tube voltage, image noise will increase (2). This can be resolved by increasing the tube current at the cost of additional dose (3). In clinical practice, this tube current increase might...

SinceAugust2010, three different scanning protocols were used on one multi-slice CT scanner (Definition AS+, Siemens, Germany) for arterial phase imaging.Initially, the tube voltage was fixed at 120 kV.Next, the tube voltage was manually selected (80 or 100 kV) based on the patient's weight.Finally, the tube voltage was automatically selected by the scanner's software based on patient's weight and tissue type of interest,while taking the power limitations of the x-ray tube into account (Care kV option). For each protocol, the mAs value was adapted accordingly. Patients...

Ten patients, 4 female and 6 male, were included. Mean age was 66.8 years (range 37-78 years). All patients had a stable lateral size.Three patients underwentonly2CT examinations, with manually selected tube voltage (figure 1)and automated selected tube voltage (figure 2),respectively. All other patients underwent alsothe CT examination with fixed tube voltage of 120 kV (figure 3). For5 patients, the automated protocol increased the manuallyselected voltage of 80 kV to 100 kVin favor of soft tissue visualization.For the remainder,tube voltagesdid not change.Compared with the fixed 120...

Automated tube voltage selection robustly optimizes arterial phase liverCT. One should be aware of the trade-off between dose saving optimized for soft tissue visualization and for vascular visualization.

1 Marin D, Nelson RC, Schindera ST, et al. (2009) Hypervascular Liver Tumors: Low Tube Voltage, High Tube Current Multidetector CT during Late Hepatic Arterial Phase for Detection—Initial Clinical Experience. Radiology, 251:771–779. 2. Lee KH, Lee JM, Moon SK, et al. (2012) Attenuation-based automatic tube voltage selection and tube current modulation for dose reduction at contrast-enhanced liver CT. Radiology, 265:437-447. doi: radiol.12112434 [pii] 10.1148/radiol.12112434 3. Brink JA, Morin RL (2012) Size-specific dose estimation for CT: how should it be used and what does it mean?...

Address correspondence to: François Willemssen, MD Department of Radiology Erasmus Medical Centre University of Rotterdam The Netherlands Email: [email protected]