Ranish Deedar Ali Khawaja MD, Presenter: Nothing to Disclose

Sjirk Jan Westra MD, Abstract Co-Author: Nothing to Disclose

Mannudeep K. S. Kalra MD, Abstract Co-Author: Nothing to Disclose

Ruth Lim MD, Abstract Co-Author: Consultant, Alexion Pharmaceuticals, Inc Officer, New England PET Imaging System

Michael Stanley Gee MD, PhD, Abstract Co-Author: Nothing to Disclose

Katherine Nimkin MD, Abstract Co-Author: Nothing to Disclose

Atul Padole MD, Abstract Co-Author: Nothing to Disclose

Roberto Lo Gullo MD, Abstract Co-Author: Nothing to Disclose

Sarabjeet Singh MD, Abstract Co-Author: Research Grant, Siemens AG Research Grant, Toshiba Corporation Research Grant, General Electric Company Research Grant, Koninklijke Philips NV

To assess lesion detection and image quality with hybrid (adaptive statistical iterative reconstruction [ASIR]) and pure (model-based iterative reconstruction [MBIR]) algorithms in pediatric chest CT examinations at submillisievert (SubmSv, <1 mSv) radiation dose. 

This IRB-approved study included 180 examinations for 97 patients who underwent routine chest CT on 64-slice MDCT (750HD Discovery, GE Healthcare). Sub-mSv (n, 90 CT exams; 9±5 years, 61% boys; median weight 24kg) and controls (size-matched with an estimated effective dose ≥1 mSv; n, 90; 9±6 years 54% boys; median weight 28kg) were assessed for lesion detection, conspicuity, diagnostic confidence and diagnostic acceptability for lesion characterization. Sub-mSv CT exams were reconstructed with ASIR60% (n, 60 CT) and MBIR (n, 30) whereas control CT exams were reconstructed with ASIR30%-60%. Independent & blinded evaluation for subjective image quality was performed for image noise, contrast, presence of artifacts & visibility of small structures. Data were analyzed with ANOVA and multiple-paired t tests.

Radiation dose between control-CT (mean SSDE, 3.8 mGy [~2.5 mSv]) and Sub-mSv CT (mean SSDE, 2.4 mGy [~0.6 mSv]) were statistically different by 76% (P.0001). A total of 199 lesions were identified in controls (n=, 61), Sub-mSv-ASIR (n, 99) & Sub-mSv-MBIR exams (n, 39). Lesions  on both control- and Sub-mSv-exams (ASIR & MBIR) were well seen with sharp margins. The diagnostic confidence and acceptability were equal in control & Sub-mSv exams. There was no difference in the subjective image noise evaluation in control & Sub-mSv ASIR/MBIR exams (P=0.9). Sub-mSv exams had both excellent visibility of small structures and image contrast comparable to control-ASIR exams (P=0.9). Streak & beam hardening artifacts were present in both Sub-mSv-ASIR & control-ASIR exams without interfering with diagnostic decision making.    

Implementation of hybrid (ASIR) and pure model iterative reconstruction technique (MBIR) successfully enabled submillisievert radiation dose for pediatric chest CT while maintaining image quality and diagnostic confidence.

ASIR- and MBIR- enabled indication-based CT protocols allow optimal clinical evaluation in submillisievert pediatric chest CT examinations.

Khawaja, R, Westra, S, Kalra, M, Lim, R, Gee, M, Nimkin, K, Padole, A, Lo Gullo, R, Singh, S, Sub-millisievert Pediatric Chest CT: Implementation of Hybrid (ASIR) and Pure (MBIR) Iterative Reconstruction Techniques for Substantial Dose Reduction.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14045447.html