Iterative reconstruction reduces abdominal CT dose

Eur J Radiol. 2012 Jul;81(7):1483-7. doi: 10.1016/j.ejrad.2011.04.021. Epub 2011 May 2.


Objective: In medical imaging, lowering radiation dose from computed tomography scanning, without reducing diagnostic performance is a desired achievement. Iterative image reconstruction may be one tool to achieve dose reduction. This study reports the diagnostic performance using a blending of 50% statistical iterative reconstruction (ASIR) and filtered back projection reconstruction (FBP) compared to standard FBP image reconstruction at different dose levels for liver phantom examinations.

Methods: An anthropomorphic liver phantom was scanned at 250, 185, 155, 140, 120 and 100 mAs, on a 64-slice GE Lightspeed VCT scanner. All scans were reconstructed with ASIR and FBP. Four readers evaluated independently on a 5-point scale 21 images, each containing 32 test sectors. In total 672 areas were assessed. ROC analysis was used to evaluate the differences.

Results: There was a difference in AUC between the 250 mAs FBP images and the 120 and 100 mAs FBP images. ASIR reconstruction gave a significantly higher diagnostic performance compared to standard reconstruction at 100 mAs.

Conclusion: A blending of 50-90% ASIR and FBP may improve image quality of low dose CT examinations of the liver, and thus give a potential for reducing radiation dose.

MeSH terms

  • Algorithms
  • Area Under Curve
  • Humans
  • Liver / diagnostic imaging*
  • Phantoms, Imaging
  • ROC Curve
  • Radiation Dosage*
  • Radiographic Image Interpretation, Computer-Assisted
  • Radiography, Abdominal / methods*
  • Sensitivity and Specificity
  • Tomography, X-Ray Computed / methods*