Michelle Claire Williams MBCHB, BSC, Presenter: Speaker, Toshiba Corporation

Nick Weir PhD, Abstract Co-Author: Nothing to Disclose

Andrew John Baird, Abstract Co-Author: Nothing to Disclose

Saeed Mirsadraee MD, PhD, Abstract Co-Author: Nothing to Disclose

Edwin J R Van Beek MD, PhD, Abstract Co-Author: Research support, Toshiba Corporation Research support, Siemens AG Founder and owner, QCTIS, Inc Speaker, Toshiba Corporation Speaker, Vital Images Inc

John H. Reid, Abstract Co-Author: Nothing to Disclose

David Ernest Newby PHD, MRCP, Abstract Co-Author: Nothing to Disclose

Radiation dose is a major health care concern. We assessed the effect of two iterative reconstruction algorithms (AIDR and AIDR3D) and individualised, automatic tube current selection on radiation dose and image quality in computed tomography coronary angiography (CTCA).

In a single centre cohort study 695 patients underwent electrocardiogram gated CTCA using a 320 multidetector scanner. Images from group 1 (n=168) were reconstructed with a filtered back projection reconstruction algorithm (QDS+). Iterative reconstruction was used for group 2 (AIDR version 1, n=386) and group 3 (AIDR3D, n=141). Tube current and voltage was selected based on body mass index (BMI) for groups 1 and 2. For group 3 tube voltage was selected based on BMI (below 30, 100kV; above 30, 120kV) and tube current was selected automatically based on scout image attenuation. Dose length product (DLP) was recorded and subjective image quality was graded on a four-point scale (1 excellent to 4 non-diagnostic).

There was no difference between groups in age (59 (57-61) vs 58 (57-59) vs 58 (56-61), p 0.447), body mass index (30 (29-31) vs 30 (29-30) vs 29 (28-30), p 0.6), heart rate (61 (59-63) vs 61 (59-62) vs 58 (56-59), p 0.055) or z-axis volume size (median 128mm for all groups, p0.082). Image quality improved with iterative reconstruction and automatic tube current selection (1.4 (1.3-1.5) vs 1.2 (1.1-1.2) vs 1.1 (1-1.1), p <0.001) and radiation dose was decreased (283 (261-305) vs 249 (236-263) vs 180 (160-201), p<0.001).

The application of the latest iterative reconstruction algorithm and individualised automatic tube current selection led to a 36% reduction in radiation dose in CTCA.

CTCA is an increasing source of population radiation exposure and the application of patient tailored imaging protocols and iterative reconstruction can dramatically reduce radiation exposure.

Williams, M, Weir, N, Baird, A, Mirsadraee, S, Van Beek, E, Reid, J, Newby, D, Iterative Reconstruction and Individualized Automatic Tube Current Selection Reduce Radiation Dose While Maintaining Image Quality in 320 Multidetector Computed Tomography Coronary Angiography.  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12030885.html