Sasi Rekha Ganga Raju, Presenter: Nothing to Disclose

Donya Ahmed Al-Hassan MD, Abstract Co-Author: Nothing to Disclose

Jonathon Avrom Leipsic MD, Abstract Co-Author: Speakers Bureau, General Electric Company Speakers Bureau, Edwards Lifesciences Corporation Consultant, Heartflow, Inc Consultant, Circle Cardiovascular Imaging Inc

Don D. Sin MD, FRCPC, Abstract Co-Author: Nothing to Disclose

Harvey Owen Coxson PhD, Abstract Co-Author: Research Grant, GlaxoSmithKline plc Contract, GlaxoSmithKline plc Contract, Olympus Corporation Steering Committee, GlaxoSmithKline plc

Cameron John Hague MD, Abstract Co-Author: Nothing to Disclose

Kevin Kai Ming Ho MBBS, Abstract Co-Author: Nothing to Disclose

Natasha Krowchuk, Abstract Co-Author: Nothing to Disclose

Jennifer Deryn Ellis MD, Abstract Co-Author: Nothing to Disclose

The purpose of this research is to examine the role that differing levels of adaptive statistical iterative reconstruction (ASIR) have on the qualitative and quantitative assessment of smoking related lung disease.

52 patients undergoing clinically indicated low dose computed tomographic (CT) exams of the chest (100 kVp, and 65mAs), with reconstruction of data with different levels of blended ASIR (0, 40 and 100%) were consented. Qualitative assessment of CT datasets were performed by two thoracic trained radiologists blinded to clinical history, spirometry and quantitative data for presence of emphysema (%/lung zone) and degree of respiratory bronchiolitis (RB). Quantitative analysis was performed to assess emphysema and airway measures of COPD (Apollo, VIDA Diagnostics). IRB approval was obtained.

The application of ASIR results in alterations in both qualitative and quantitative assessment of smoking related lung disease. As levels of ASIR increased both readers scored more RB (p <0.05). As levels of ASIR changed significant (p<0.05) differences were demonstrated for % below -950Hu, % of density below the 15th percentile, number of airways measured, and airway thickness (Pi10mm). The effect ASIR has on emphysema quantification is accentuated in patients with higher BMI. The differences between the attenuation histograms at different levels of applied ASIR in patients with elevated BMI’s are maximized. As such, differences in emphysema quantification in these patients are also maximized.

The use of ASIR alters both the qualitative and quantitative assessment of smoking related lung disease. Increasing levels of ASIR result in a potential overestimation of the degree of respiratory bronchiolitis. Quantitative assessment demonstrates decreased levels of emphysema, increased airway thickness and diminished ability to count distal airways as levels of ASIR increase.

While iterative reconstruction algorithms such as ASIR are becoming widespread in their clinical use as an avenue to reduce radiation dose, their application with regards to assessment of smoking related lung disease both qualitatively and quantitatively needs to be utilized with caution.

Ganga Raju, S, Al-Hassan, D, Leipsic, J, Sin, D, Coxson, H, Hague, C, Ho, K, Krowchuk, N, Ellis, J, The Effect of Different Levels of Iterative Reconstruction on Qualitative and Quantitative Assessment of Smoking Related Lung Disease.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14010141.html