Namita Sharma Gandhi MD, Presenter: Nothing to Disclose

Brian Robert Herts MD, Abstract Co-Author: Research Grant, Siemens AG

Andrei S. Purysko MD, Abstract Co-Author: Nothing to Disclose

Erick Marc Remer MD, Abstract Co-Author: Nothing to Disclose

David Marc Einstein MD, Abstract Co-Author: Nothing to Disclose

Noushin Vahdat MD, Abstract Co-Author: Nothing to Disclose

Devaraju Kanmaniraja MD, Abstract Co-Author: Nothing to Disclose

Myra Kay Feldman MD, Abstract Co-Author: Nothing to Disclose

Christopher Peter Coppa MD, Abstract Co-Author: Nothing to Disclose

Nancy A. Obuchowski PhD, Abstract Co-Author: Research Consultant, Siemens AG Research Consultant, Hologic, Inc Research Consultant, CVUS Research Consultant, Elucid Bioimaging Inc

Ajit Harishkumar Goenka MD, Abstract Co-Author: Nothing to Disclose

Mark E. Baker MD, Abstract Co-Author: Research Consultant, Bracco Group Researcher, Siemens AG Research support, Siemens AG

To compare diagnostic accuracy and image quality between sinogram affirmed iterative reconstruction (SAFIRE) and filtered back projection (FBP) at half and full dose for diagnosis of active inflammatory terminal ileal (TI) Crohn’s disease on CT Enterography (CTE).

IRB approved, HIPAA compliant, Retrospective, Single center study. Study cohort of 90 patients: active TI Crohns disease (n=45) and Normal (N=45). All patients had a CTE on a dual-source CT (100% dose) with FBP reconstruction. Single source (50% dose) data was extracted and reconstructed with FBP & SAFIRE version 3 (strength 3 & 4). CTDIvol full dose mean=13.1 mGy, median=7.36 mGy, range- 3.62-44.5 mGy; CTDIvol ½ dose mean=6.55 mGy, median=3.68 mGy, range- 1.81-22.25 mGy. Using a 5-point scale, 8 readers evaluated the studies, randomized & blinded to the clinical history, dose and reconstruction method, separately for subjective image quality and presence or absence of active TI Crohn’s disease. Statistical evaluation included multireader multi-comparison ROC analysis, with nonparametric methods and non-inferiority analysis at a margin of −0.05.

Each half-dose reconstruction had a significantly higher proportion of non-diagnostic or suboptimal images compared to full dose FBP (mean frequency of such images at ½ dose FBP: 0.117; ½ dose SAFIRE strength 3: 0.054 & ½ dose SAFIRE strength 4: 0.054; full-dose FBP: 0.017) with all p values <0.001 (adjusted for difference test) (95% CI -0.131, -0.016). The readers’ mean accuracies with ½ dose were significantly non-inferior to full dose FBP (i.e. no more than 0.05 less than)(½ dose FBP: 0.908; ½ dose SAFIRE strength 3: 0.935; ½ dose SAFIRE strength 4: 0.924; full-dose FBP: 0.908) with p-values of 0.003 (CI: -.031,.031) for ½ dose FBP, <0.001(CI -0.041, 0.013) for ½ dose Safire strength 3 and <0.001 (CI-0.039, 0.007) for ½ dose Safire strength 4.

The diagnostic accuracies of half dose CTE with FBP, SAFIRE version 4 (strength 3 & 4) are statistically non-inferior to full dose CTE for diagnosing active inflammatory terminal ileal Crohn’s disease despite an inferior subjective image quality.

Radiation dose reduction can be achieved in patients with Crohns disease who often undergo multiple CT Enterography studies to assess for active inflammation.

Gandhi, N, Herts, B, Purysko, A, Remer, E, Einstein, D, Vahdat, N, Kanmaniraja, D, Feldman, M, Coppa, C, Obuchowski, N, Goenka, A, Baker, M, Diagnostic Accuracy of Sinogram Affirmed Iterative Reconstruction and Filtered Back Projection in CTE at Half Dose for Active Inflammatory Terminal Ileal Crohn’s Disease: A Multireader Study.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14008157.html