Xiao Zhu Lin BA, Presenter: Nothing to Disclose

Isao Tanaka, Abstract Co-Author: Nothing to Disclose

JianYing Li, Abstract Co-Author: Employee, General Electric Company

Eiko Ueno MD, Abstract Co-Author: Nothing to Disclose

Yun Shen PhD, Abstract Co-Author: Employee, General Electric Company Researcher, General Electric Company

Kemin Chen MD, PhD, Abstract Co-Author: Nothing to Disclose

To assess the dose reduction potential with advanced reconstruction algorithms (model-based iterative reconstruction (Veo) and adaptive statistical iterative reconstruction (ASIR)) by comparing image noise and contrast-noise-ratio (CNR) with the filtered back projection (FBP) reconstructions.

11 subjects underwent contrast enhanced abdominal CT with different indications on Discovery CT750HD was included. In addition to the 5mm slice thickness images with FBP for routine diagnosis, 3 sets of 0.625mm slice thickness CT images were reconstructed with FBP, 50% ASIR and Veo. Image noises of the background, liver, pancreas, spleen, portal vein (PV), and CNR between PV and liver in the portal venous phase were measured and compared within the recon groups.

For the comparison with same image slice thickness, the average image noise reduction with 50%ASIR and Veo compared with FBP for the background, liver, pancreas, spleen and portal vein were (27.6%, 30.1%, 30.6%, 31.7% and 30.9%) and (62.1%, 57.3%, 57.3%, 54.1% and 54.0%), respectively. The CNR for PV with 50%ASIR and Veo was improved by 40% and 128%, respectively compared with that of FBP. All differences were statistically significant (p<0.001). Even at the much reduced slice thickness of 0.625mm (1/8 of 5mm), Veo reconstructions revealed statistically lower image noises for the background, liver, pancreas, spleen and portal vein, respectively (p<0.05): (5.5±0.8HU, 10.2±1.5HU, 10.6±1.4HU, 12.3±2.0HU, and 13.4±2.8HU) with Veo and (6.6±1.7HU, 12.6±1.2HU, 13.0±1.9HU, 14.0±2.3HU, and 16.0±2.3HU) with FBP. CNR for the portal vein at 5.7±2.1 with Veo was also much higher than the 0.5±0.3 with FBP (p<0.001).

Advanced reconstruction algorithms greatly reduced image noise and improved image CNR. With Veo reconstruction, it was possible to reduce dose by 80% if similar noise as the current FBP images was acceptable.

Veo and ASIR reconstruction techniques have the ability to reduce radiation dose through their improvement in image quality compared with the current algorithms such as FBP.

Lin, X, Tanaka, I, Li, J, Ueno, E, Shen, Y, Chen, K, Dose Reduction Potential with Advanced Reconstruction Algorithms: Assessment of Image Noise and Image Quality in Abdominal CT.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11014348.html