Christoph Schabel MD, Presenter: Speaker, Siemens AG

Malte Niklas Bongers, Abstract Co-Author: Nothing to Disclose

Stefanie Mangold MD, Abstract Co-Author: Nothing to Disclose

Bernhard Krauss PhD, Abstract Co-Author: Employee, Siemens AG

Konstantin Nikolaou MD, Abstract Co-Author: Speakers Bureau, Siemens AG Speakers Bureau, Bracco Group Speakers Bureau, Bayer AG

Christoph Karl Thomas MD, Abstract Co-Author: Speaker, Siemens AG

Ilias Tsiflikas MD, Abstract Co-Author: Nothing to Disclose

Ulrich Grosse MD, Abstract Co-Author: Nothing to Disclose

To evaluate a novel monoenergetic postprocessing algorithm (MEI+) with newly available dual energy voltage combinations of a 3rd generation dual source CT (Somatom Definition Force, Siemens, Forchheim, Germany) in a phantom model and in patients with poor intrahepatic contrast enhancement.

An anthropomorphic phantom which contained iodine of different dilutions, was scanned using a 3rd generation dual-source CT scanner with five different voltage combinations (70/150, 80/150, 90/150, 100/150, 80/140kV) with additional tin filter for 150kV and single energy at 120kV (SE). CTDI was kept constant throughout all scans. Optimal contrast images (OC), sole low kV (70, 80, 90, 100kV) images and traditional monoenergetic images (MEI) and MEI+ images (40keV to 190 keV) were calculated. MEI+ is a novel technique which combines the MEI algorithm with an advanced noise reduction algorithm. The contrast-to-noise ratio (CNR) between two different iodine dilutions were measured. Furthermore dual energy late-phase imaging of the liver which was acquired with a 2nd generation dual energy CT (Somatom Definition Flash, Siemens, Germany) was retrospectively evaluated in 25 patients with approval of local IRB and waiver of written informed consent. Measurements were used as a model for poor intrahepatic contrast enhancement.

MEI+ had highest CNR at 40keV (3.99-4.63 at 70/150kV) compared to MEI (2.34-3.89 at 60-70keV and 70/150kV), OC (3.02-4.35 at 70/150kV), sole low kV images (2.87-3.93 at 70kV) and SE (2.32). MEI, MEI+ (at low keV settings) and OC achieved highest CNR for 70/150kV scans but only MEI+ and OC were able to surpass sole 70kV images. In late phase imaging of the liver MEI+ increased CNR (2.1 ± 0.6 at 40keV) between liver veins and parenchyma significantly compared to MEI (1.0 ± 0.4 at 70keV) and sole 100 kV images (1.0 ± 0.3).

MEI+ overcomes noise limitations of MEI at low virtual keV levels and increases CNR by about 100% (72-100%) compared to SE at an equal radiation dose. Images acquired with 90/150kV and 100/150kV gain most CNR from MEI+ and are feasible in most patients due to power reserves of the scanning system.

An increase in CNR can be used to reduce contrast dose or radiation dose in patients.

Schabel, C, Bongers, M, Mangold, S, Krauss, B, Nikolaou, K, Thomas, C, Tsiflikas, I, Grosse, U, Evaluation of a Novel Monoenergetic Postprocessing Algorithm with Newly Available Dual Energy Voltage Combinations of a 3rd Generation Dual Source CT in a Phantom Model and a Patient Study.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14013309.html