Value of knowledge-based iterative model reconstruction in low-kV 256-slice coronary CT angiography

Yuki, Hideaki; Utsunomiya, Daisuke; Funama, Yoshinori; Tokuyasu, Shinichi; Namimoto, Tomohiro; Hirai, Toshinori; Itatani, Ryo; Katahira, Kentaro; Oshima, Shuichi; Yamashita, Yasuyuki

doi:10.1016/j.jcct.2013.12.010

Cited by 54 publications

(28 citation statements)

References 25 publications

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“…This significant improvement in CNR is based on the IMR induced noise reduction. Two recent studies on low kilo voltage coronary CT angiography using IMR supported our results by reporting significant noise reductions and improvement of CNR and image quality in angiographic studies [31, 32]. IMR is a knowledge-based IR approach in which reconstruction becomes a process of optimization that takes into account the data statistics, image statistics, as well as system models [17].…”

Section: Discussionsupporting

confidence: 77%

“…IMR is a knowledge-based IR approach in which reconstruction becomes a process of optimization that takes into account the data statistics, image statistics, as well as system models [17]. It generates optimal images by iteratively minimizing the difference between acquired data and their ideal form, providing noise and artifact free images [17, 31]. The consecutive improvement of CNR offers the opportunity to reduce the amount of CM.…”

Section: Discussionmentioning

confidence: 99%

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CT Pulmonary Angiography at Reduced Radiation Exposure and Contrast Material Volume Using Iterative Model Reconstruction and iDose4 Technique in Comparison to FBP

et al. 2016

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PurposeTo assess image quality of CT pulmonary angiography (CTPA) at reduced radiation exposure (RD-CTPA) and contrast medium (CM) volume using two different iterative reconstruction (IR) algorithms (iDose4 and iterative model reconstruction (IMR)) in comparison to filtered back projection (FBP).Materials and Methods52 patients (body weight < 100 kg, mean BMI: 23.9) with suspected pulmonary embolism (PE) underwent RD-CTPA (tube voltage: 80 kV; mean CTDIvol: 1.9 mGy) using 40 ml CM. Data were reconstructed using FBP and two different IR algorithms (iDose4 and IMR). Subjective and objective image quality and conspicuity of PE were assessed in central, segmental, and subsegmental arteries.ResultsNoise reduction of 55% was achieved with iDose4 and of 85% with IMR compared to FBP. Contrast-to-noise ratio significantly increased with iDose4 and IMR compared to FBP (p<0.05). Subjective image quality was rated significantly higher at IMR reconstructions in comparison to iDose4 and FBP. Conspicuity of central and segmental PE significantly improved with the use of IMR. In subsegmental arteries, iDose4 was superior to IMR.ConclusionsCTPA at reduced radiation exposure and contrast medium volume is feasible with the use of IMR, which provides improved image quality and conspicuity of pulmonary embolism in central and segmental arteries.

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Section: Discussionsupporting

confidence: 77%

Section: Discussionmentioning

confidence: 99%

CT Pulmonary Angiography at Reduced Radiation Exposure and Contrast Material Volume Using Iterative Model Reconstruction and iDose4 Technique in Comparison to FBP

et al. 2016

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“…Finally, we did not include assessment of image quality in this study as our focus is to compare the radiation dose among these different CT scanners. Recent developments in CCTA (both prospectively and retrospectively ECG-triggering) with use of iterative reconstruction (IR) algorithms have been shown to significantly improve image quality while reducing radiation dose to a greater extent [32, 33]. Thus, further studies with testing of these IR techniques on different CT scanners are needed.…”

Section: Discussionmentioning

confidence: 99%

Recent Update on Radiation Dose Assessment for the State-of-the-Art Coronary Computed Tomography Angiography Protocols

Tan

Yeong

et al. 2016

PLoS ONE

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ObjectivesThis study aimed to measure the absorbed doses in selected organs for prospectively ECG-triggered coronary computed tomography angiography (CCTA) using five different generations CT scanners in a female adult anthropomorphic phantom and to estimate the effective dose (HE).Materials and MethodsProspectively ECG-triggered CCTA was performed using five commercially available CT scanners: 64-detector-row single source CT (SSCT), 2 × 32-detector-row-dual source CT (DSCT), 2 × 64-detector-row DSCT and 320-detector-row SSCT scanners. Absorbed doses were measured in 34 organs using pre-calibrated optically stimulated luminescence dosimeters (OSLDs) placed inside a standard female adult anthropomorphic phantom. HE was calculated from the measured organ doses and compared to the HE derived from the air kerma-length product (PKL) using the conversion coefficient of 0.014 mSv∙mGy-1∙cm-1 for the chest region.ResultsBoth breasts and lungs received the highest radiation dose during CCTA examination. The highest HE was received from 2 × 32-detector-row DSCT scanner (6.06 ± 0.72 mSv), followed by 64-detector-row SSCT (5.60 ± 0.68 and 5.02 ± 0.73 mSv), 2 × 64-detector-row DSCT (1.88 ± 0.25 mSv) and 320-detector-row SSCT (1.34 ± 0.48 mSv) scanners. HE calculated from the measured organ doses were about 38 to 53% higher than the HE derived from the PKL-to-HE conversion factor.ConclusionThe radiation doses received from a prospectively ECG-triggered CCTA are relatively small and are depending on the scanner technology and imaging protocols. HE as low as 1.34 and 1.88 mSv can be achieved in prospectively ECG-triggered CCTA using 320-detector-row SSCT and 2 × 64-detector-row DSCT scanners.

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“…[13–15] Unlike HIR, IMR is an advanced iterative reconstruction that applies a knowledge-based approach to accurately determine the data and image statistical models that are coupled with the model of the CT system and involve the geometry and physical characteristics of the CT scanner. [16] It is mathematically more complex and accurate, and theoretically enables lower image noise and better image quality. Consistent with the theory, our results revealed that IMR significantly improved both objective and subjective image quality at LD chest scans using < 50% of routine tube current (Figs.…”

Section: Discussionmentioning

confidence: 99%

Chest CT with iterative reconstruction algorithms for airway stent evaluation in patients with malignant obstructive tracheobronchial diseases

Zhang²,

Wang³

et al. 2016

Medicine

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The aim of the study was to investigate the image quality of low-dose CT images with different reconstruction algorithms including filtered back projection (FBP), hybrid iterative reconstruction (HIR), and iterative model reconstruction (IMR) algorithms by comparison of routine dose images with FBP reconstruction, in patients with malignant obstructive tracheobronchial diseases.In total, 60 patients (59 ± 9.3 years, 37 males) with airway stent who are randomly assigned into 2 groups (routine-dose [RD] and low-dose [LD] group, 30 for each) underwent chest CT on a 256-slice CT (RD-group 120 kV, 250 mAs, LD-group 120 kV, 120 mAs). Images were reconstructed with filtered back projection (FBP) algorithm in the RD group, whereas with FBP, HIR and IMR algorithms in the LD group. Effective radiation dose of both groups was recorded. Image-quality assessment was performed by 2 radiologists according to structure demarcation near stents, artifacts, noise, and diagnostic confidence using a 5-point scale (1 [poor] to 5 [excellent]). Image noise and CNR were measured.The effective radiation dose of LD group was reduced 52.7% compared with the RD group (10.8 mSv ± 0.58 vs 5.1 mSv ± 0.26, P = 0.00). LD-IMR images enabled lowest image noise and best subjective image quality scores of all 4 indices, when compared with RD images reconstructed with FBP (RD-FBP) images (all P < 0.05). LD images reconstructed with and with HIR (LD-HIR) images enabled higher score in subjective image quality of artifacts (P < 0.05), whereas it showed no difference in the other subjective image-quality indices and image noise. Significant higher image noise and lower score of subjective image quality were observed in LD-FBP images (all P < 0.05).Both IMR and HIR improved image quality of low-dose chest CT by comparison of routine dose images reconstructed with FBP. Meanwhile, IMR allows further image quality improvement than HIR.

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Value of knowledge-based iterative model reconstruction in low-kV 256-slice coronary CT angiography

Cited by 54 publications

References 25 publications

CT Pulmonary Angiography at Reduced Radiation Exposure and Contrast Material Volume Using Iterative Model Reconstruction and iDose4 Technique in Comparison to FBP

CT Pulmonary Angiography at Reduced Radiation Exposure and Contrast Material Volume Using Iterative Model Reconstruction and iDose4 Technique in Comparison to FBP

Recent Update on Radiation Dose Assessment for the State-of-the-Art Coronary Computed Tomography Angiography Protocols

Chest CT with iterative reconstruction algorithms for airway stent evaluation in patients with malignant obstructive tracheobronchial diseases

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