scholarly journals Iterative Reconstruction for Head CT: Effects on Radiation Dose and Image Quality

2014 ◽  
Vol 41 (5) ◽  
pp. 620-625 ◽  
Author(s):  
Michael D. Rivers-Bowerman ◽  
Jai Jai Shiva Shankar
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Iterative Reconstruction ◽  
Image Noise ◽  
Rank Test ◽  
Head Ct ◽  
Institutional Review ◽  
Signed Rank Test ◽  
Small Structure ◽  
Adult Head

AbstractBackgroundIterative reconstruction has been reported to reduce radiation dose in CT, while preserving and even improving image quality. The purpose of this study was to evaluate the effects of sinogram-affirmed iterative reconstruction (SAFIRE) on radiation dose reduction and image quality for noncontrast adult head CT and to compare SAFIRE with conventional filtered back-projection (FBP) reconstruction.MethodsInstitutional review board approval was obtained for this retrospective analysis of head CT scans reconstructed with SAFIRE and/or FBP for 107 patients. Radiation dose parameters were recorded from scanner-generated CT dose reports. Signal-to-noise and contrast-to-noise ratios (SNR, CNR) were calculated from gray and white matter (GM, WM) attenuation measurements. Image noise, artifacts, GM-WM differentiation, small structure visibility, and sharpness were graded by two readers. Statistical analysis included the independent-samples t test for quantitative data, the related samples Wilcoxon signed-rank test for qualitative data, the coefficient of repeatability for intraobserver variation, and κ statistics for interobserver agreement.ResultsMean effective dose was significantly reduced with SAFIRE from 2.0 to 1.7 mSv (p<0.0001). SAFIRE also significantly improved GM SNR, WM SNR, and GM-WM CNR (p<0.0001). Significant reductions in image noise and posterior fossa artifact as well as improvements in GM-WM differentiation, small structure visibility, and sharpness were noted with SAFIRE (P<0.005).ConclusionsSAFIRE for noncontrast adult head CT reduces patient radiation dose by 15% for the settings employed at our institution, while significantly improving multiple quantitative and qualitative measures of image quality.

Ultra-low-dose lung screening CT with model-based iterative reconstruction: an assessment of image quality and lesion conspicuity

2017 ◽  
Vol 59 (5) ◽  
pp. 553-559 ◽  
Author(s):  
Yun Hye Ju ◽  
Geewon Lee ◽  
Ji Won Lee ◽  
Seung Baek Hong ◽  
Young Ju Suh ◽  
...  
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Iterative Reconstruction ◽  
Low Dose ◽  
Image Noise ◽  
Low Dose Ct ◽  
Group 5 ◽  
Lung Screening ◽  
Lesion Conspicuity ◽  
Group 1

Background Reducing radiation dose inevitably increases image noise, and thus, it is important in low-dose computed tomography (CT) to maintain image quality and lesion detection performance. Purpose To assess image quality and lesion conspicuity of ultra-low-dose CT with model-based iterative reconstruction (MBIR) and to determine a suitable protocol for lung screening CT. Material and Methods A total of 120 heavy smokers underwent lung screening CT and were randomly and equally assigned to one of five groups: group 1 = 120 kVp, 25 mAs, with FBP reconstruction; group 2 = 120 kVp, 10 mAs, with MBIR; group 3 = 100 kVp, 15 mAs, with MBIR; group 4 = 100 kVp, 10 mAs, with MBIR; and group 5 = 100 kVp, 5 mAs, with MBIR. Two radiologists evaluated intergroup differences with respect to radiation dose, image noise, image quality, and lesion conspicuity using the Kruskal–Wallis test and the Chi-square test. Results Effective doses were 61–87% lower in groups 2–5 than in group 1. Image noises in groups 1 and 5 were significantly higher than in the other groups ( P < 0.001). Overall image quality was best in group 1, but diagnostic acceptability of overall image qualities in groups 1–3 was not significantly different (all P values > 0.05). Lesion conspicuities were similar in groups 1–4, but were significantly poorer in group 5. Conclusion Lung screening CT with MBIR obtained at 100 kVp and 15 mAs enables a ∼60% reduction in radiation dose versus low-dose CT, while maintaining image quality and lesion conspicuity.

Performance Evaluation of Two Iterative Reconstruction Algorithms--MBIR and ASIR, in Low Radiation Dose and Low Contrast Dose Abdominal CT in Children

2019 ◽  
Author(s):  
Jihang Sun ◽  
Lixin Yang ◽  
Zuofu Zhou ◽  
Dan Zhang ◽  
Wei Han ◽  
...  
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Iterative Reconstruction ◽  
Image Noise ◽  
Abdominal Ct ◽  
Low Contrast ◽  
Low Radiation Dose ◽  
Contrast Dose ◽  
Contrast Enhanced Ct ◽  
Noise Ratio

Abstract Background The adverse effect of low-dose CT on image quality may be mitigated using iterative reconstructions. The purpose of this study was to evaluate the performance of the full model-based iterative reconstruction (MBIR) and adaptive statistical reconstruction (ASIR) algorithms in low radiation dose and low contrast dose abdominal contrast-enhanced CT (CECT) in children. Methods A total of 59 children (32 males and 27 females) undergoing low radiation dose (100kVp) and low contrast dose (270 mgI/ml) abdominal CECT were enrolled. The median age was 4.0 years (ranging from 0.3 to 13 years). The raw data were reconstructed with MBIR, ASIR and filtered back projection (FBP) algorithms into 6 groups (MBIR, 100%ASIR, 80%ASIR, 60%ASIR, 40%ASIR and FBP). The CT numbers, standard deviations, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of liver, pancreas, kidney and abdominal aorta were measured. Two radiologists independently evaluated the subjective image quality including the overall image noise and structure display ability on a 4-point scale with 3 being clinically acceptable. The measurements among the reconstruction groups were compared using one-way ANOVA. Results The overall image noise score and display ability were 4.00±0.00 and 4.00±0.00 with MBIR, and 3.27±0.33 and 3.25±0.43 with ASIR100%, respectively, which met the diagnostic requirement; other reconstructions couldn’t meet the diagnostic requirements. Compared with FBP images, the noise of MBIR images was reduced by 62.86%-65.73% for the respective organs (F=48.15-80.47, P<0.05), and CNR increased by 151.38%-170.69% (F=22.94-38.02, P<0.05). Conclusions MBIR or ASIR100% improves the image quality of low radiation dose and contrast dose abdominal CT in children to meet the diagnostic requirements, and MBIR has the best performance.

scholarly journals Deep Learning Versus Iterative Reconstruction for CT Pulmonary Angiography in the Emergency Setting: Improved Image Quality and Reduced Radiation Dose

Diagnostics ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 558
Author(s):  
Marc Lenfant ◽  
Olivier Chevallier ◽  
Pierre-Olivier Comby ◽  
Grégory Secco ◽  
Karim Haioun ◽  
...  
Keyword(s):  
Deep Learning ◽  
Image Quality ◽  
Radiation Dose ◽  
Iterative Reconstruction ◽  
Noise Signal ◽  
Pulmonary Angiography ◽  
Image Noise ◽  
Emergency Setting ◽  
Dose Length Product ◽  
Noise Ratio

To compare image quality and the radiation dose of computed tomography pulmonary angiography (CTPA) subjected to the first deep learning-based image reconstruction (DLR) (50%) algorithm, with images subjected to the hybrid-iterative reconstruction (IR) technique (50%). One hundred forty patients who underwent CTPA for suspected pulmonary embolism (PE) between 2018 and 2019 were retrospectively reviewed. Image quality was assessed quantitatively (image noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR)) and qualitatively (on a 5-point scale). Radiation dose parameters (CT dose index, CTDIvol; and dose-length product, DLP) were also recorded. Ninety-three patients were finally analyzed, 48 with hybrid-IR and 45 with DLR images. The image noise was significantly lower and the SNR (24.4 ± 5.9 vs. 20.7 ± 6.1) and CNR (21.8 ± 5.8 vs. 18.6 ± 6.0) were significantly higher on DLR than hybrid-IR images (p < 0.01). DLR images received a significantly higher score than hybrid-IR images for image quality, with both soft (4.4 ± 0.7 vs. 3.8 ± 0.8) and lung (4.1 ± 0.7 vs. 3.6 ± 0.9) filters (p < 0.01). No difference in diagnostic confidence level for PE between both techniques was found. CTDIvol (4.8 ± 1.4 vs. 4.0 ± 1.2 mGy) and DLP (157.9 ± 44.9 vs. 130.8 ± 41.2 mGy∙cm) were lower on DLR than hybrid-IR images. DLR both significantly improved the image quality and reduced the radiation dose of CTPA examinations as compared to the hybrid-IR technique.

Ultra-Low-Dose CT of the Thorax Using Iterative Reconstruction: Evaluation of Image Quality and Radiation Dose Reduction

2015 ◽  
Vol 204 (6) ◽  
pp. 1197-1202 ◽  
Author(s):  
Yookyung Kim ◽  
Yoon Kyung Kim ◽  
Bo Eun Lee ◽  
Seok Jeong Lee ◽  
Yon Ju Ryu ◽  
...  
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Dose Reduction ◽  
Iterative Reconstruction ◽  
Low Dose ◽  
Radiation Dose Reduction ◽  
Low Dose Ct
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