Martin J Willemink1, Annemarie M den Harder2, Wouter Foppen2, Arnold M R Schilham2, Rienk Rienks3, Eduard M Laufer3, Koen Nieman4, Pim A de Jong2, Ricardo P J Budde5, Hendrik M Nathoe3, Tim Leiner2. 1. Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands. Electronic address: m.j.willemink@gmail.com. 2. Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands. 3. Department of Cardiology, University Medical Center Utrecht, Utrecht, The Netherlands. 4. Department of Cardiology, Erasmus Medical Center, Rotterdam, The Netherlands; Department of Radiology, Erasmus Medical Center, Rotterdam, The Netherlands. 5. Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands; Department of Radiology, Erasmus Medical Center, Rotterdam, The Netherlands.
Abstract
OBJECTIVE: To assess the maximally achievable computed tomography (CT) dose reduction for coronary artery calcium (CAC) scoring with iterative reconstruction (IR) by using phantom-experiments and a systematical within-patient study. METHODS: Our local institutional review-board approved this study and informed consent was obtained from all participants. A phantom and patient study were conducted with 30 patients (23 men, median age 55.0 (52.0-56.0) years) who underwent 256-slice electrocardiogram-triggered CAC-scoring at four dose levels (routine, 60%, 40%, and 20%-dose) in a single session. Tube-voltage was 120 kVp, tube-current was lowered to achieve stated dose levels. Data were reconstructed with filtered back-projection (FBP) and three IR levels. Agatston, volume and mass scores were determined with validated software and compared using Wilcoxon signed ranks-tests. Subsequently, patient reclassification was analyzed. RESULTS: The phantom study showed that Agatston scores remained nearly stable with FBP between routine-dose and 40%-dose and increased substantially at lower dose. Twenty-three patients (77%) had coronary calcifications. For Agatston scoring, one 40%-dose and six 20%-dose FBP reconstructions were not interpretable due to noise. In contrast, with IR all reconstructions were interpretable. Median Agatston scores increased with FBP from 26.1 (5.2-192.2) at routine-dose to 60.5 (11.6-251.7) at 20% dose. However, IR lowered Agatston scores to 22.9 (5.9-195.5) at 20%-dose and strong IR (level 7) with Agatston reclassifications in 15%. CONCLUSION: IR allows for CAC-scoring radiation dose reductions of up to 80% resulting in effective doses between 0.15 and 0.18 mSv. At these dose-levels, reclassification-rates remain within 15% if the highest IR-level is applied.
OBJECTIVE: To assess the maximally achievable computed tomography (CT) dose reduction for coronary artery calcium (CAC) scoring with iterative reconstruction (IR) by using phantom-experiments and a systematical within-patient study. METHODS: Our local institutional review-board approved this study and informed consent was obtained from all participants. A phantom and patient study were conducted with 30 patients (23 men, median age 55.0 (52.0-56.0) years) who underwent 256-slice electrocardiogram-triggered CAC-scoring at four dose levels (routine, 60%, 40%, and 20%-dose) in a single session. Tube-voltage was 120 kVp, tube-current was lowered to achieve stated dose levels. Data were reconstructed with filtered back-projection (FBP) and three IR levels. Agatston, volume and mass scores were determined with validated software and compared using Wilcoxon signed ranks-tests. Subsequently, patient reclassification was analyzed. RESULTS: The phantom study showed that Agatston scores remained nearly stable with FBP between routine-dose and 40%-dose and increased substantially at lower dose. Twenty-three patients (77%) had coronary calcifications. For Agatston scoring, one 40%-dose and six 20%-dose FBP reconstructions were not interpretable due to noise. In contrast, with IR all reconstructions were interpretable. Median Agatston scores increased with FBP from 26.1 (5.2-192.2) at routine-dose to 60.5 (11.6-251.7) at 20% dose. However, IR lowered Agatston scores to 22.9 (5.9-195.5) at 20%-dose and strong IR (level 7) with Agatston reclassifications in 15%. CONCLUSION: IR allows for CAC-scoring radiation dose reductions of up to 80% resulting in effective doses between 0.15 and 0.18 mSv. At these dose-levels, reclassification-rates remain within 15% if the highest IR-level is applied.
Authors: Andrew D Choi; Eric S Leifer; Jeannie Yu; Sujata M Shanbhag; Kathie Bronson; Andrew E Arai; Marcus Y Chen Journal: J Cardiovasc Comput Tomogr Date: 2016-07-27
Authors: N R van der Werf; P A Rodesch; S Si-Mohamed; R W van Hamersvelt; M J W Greuter; T Leiner; L Boussel; M J Willemink; P Douek Journal: Eur Radiol Date: 2022-01-08 Impact factor: 5.315
Authors: Tobias Gassenmaier; Thomas Allmendinger; Andreas S Kunz; Maike Veyhl-Wichmann; Süleyman Ergün; Thorsten A Bley; Bernhard Petritsch Journal: Acta Radiol Open Date: 2017-05-29