Low-dose, wide-detector array thoracic aortic CT angiography using an iterative reconstruction technique results in improved image quality with lower noise and fewer artifacts

Background Iterative reconstruction techniques (IRTs) may improve image quality for low-dose imaging compared with filtered back projection (FBP) reconstruction. Objectives We compared the results of an IRT for low-dose thoracic aortic computed tomography (CT) imaging with those from FBP reconstruction. Methods Data from 50 patients who underwent 256-slice CT for evaluation of the thoracic aorta were reconstructed with FBP and an IRT (iDose 4 ) at 3 noise-reduction strengths (levels 2, 4, and 6). A blinded reader graded image quality (scale, 1–5; 5 = high diagnostic confidence) and the extent of shoulder artifact (scale, 1–5; 5 = no artifact) on all reconstructions. A second reader evaluated a subset of 20 cases to determine interreader and intrareader reproducibility. The mean and SD of attenuation were measured at 5 locations along the thoracic aorta and both subclavian arteries. Results Image noise (SD of attenuation) improved with IRT relative to FBP (aorta: FBP, 31.4 ± 8.6 HU; IRT level 2, 25.1 ± 6.9 HU; level 4, 21.7 ± 6.2 HU; level 6, 17.2 ± 5.4 HU; P P P Conclusion IRT is associated with reduced noise and shoulder artifact and allows for low-dose aortic CT imaging.