Computed tomography imaging with the Adaptive Statistical Iterative Reconstruction (ASIR) algorithm: dependence of image quality on the blending level of reconstruction

2018 ◽  
Vol 41 (2) ◽  
pp. 463-473 ◽  
Author(s):  
Patrizio Barca ◽  
Marco Giannelli ◽  
Maria Evelina Fantacci ◽  
Davide Caramella
Keyword(s):  
Computed Tomography ◽  
Image Quality ◽  
Iterative Reconstruction ◽  
Computed Tomography Imaging ◽  
Adaptive Statistical Iterative Reconstruction ◽  
Tomography Imaging ◽  
Statistical Iterative Reconstruction

scholarly journals Influence of adaptive statistical iterative reconstruction algorithm on image quality in coronary computed tomography angiography

2016 ◽  
Vol 5 (12) ◽  
pp. 205846011668488
Author(s):  
Helle Precht ◽  
Jesper Thygesen ◽  
Oke Gerke ◽  
Kenneth Egstrup ◽  
Dag Waaler ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Coronary Artery ◽  
Image Quality ◽  
Iterative Reconstruction ◽  
Computed Tomography Angiography ◽  
Coronary Computed Tomography Angiography ◽  
Reconstruction Algorithms ◽  
Adaptive Statistical Iterative Reconstruction ◽  
Coronary Computed Tomography ◽  
Statistical Iterative Reconstruction

Background Coronary computed tomography angiography (CCTA) requires high spatial and temporal resolution, increased low contrast resolution for the assessment of coronary artery stenosis, plaque detection, and/or non-coronary pathology. Therefore, new reconstruction algorithms, particularly iterative reconstruction (IR) techniques, have been developed in an attempt to improve image quality with no cost in radiation exposure. Purpose To evaluate whether adaptive statistical iterative reconstruction (ASIR) enhances perceived image quality in CCTA compared to filtered back projection (FBP). Material and Methods Thirty patients underwent CCTA due to suspected coronary artery disease. Images were reconstructed using FBP, 30% ASIR, and 60% ASIR. Ninety image sets were evaluated by five observers using the subjective visual grading analysis (VGA) and assessed by proportional odds modeling. Objective quality assessment (contrast, noise, and the contrast-to-noise ratio [CNR]) was analyzed with linear mixed effects modeling on log-transformed data. The need for ethical approval was waived by the local ethics committee as the study only involved anonymously collected clinical data. Results VGA showed significant improvements in sharpness by comparing FBP with ASIR, resulting in odds ratios of 1.54 for 30% ASIR and 1.89 for 60% ASIR ( P = 0.004). The objective measures showed significant differences between FBP and 60% ASIR ( P < 0.0001) for noise, with an estimated ratio of 0.82, and for CNR, with an estimated ratio of 1.26. Conclusion ASIR improved the subjective image quality of parameter sharpness and, objectively, reduced noise and increased CNR.

Image quality in coronary computed tomography angiography: influence of adaptive statistical iterative reconstruction at various radiation dose levels

2018 ◽  
Vol 59 (10) ◽  
pp. 1194-1202 ◽  
Author(s):  
Helle Precht ◽  
Oke Gerke ◽  
Jesper Thygesen ◽  
Kenneth Egstrup ◽  
Søren Auscher ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Image Quality ◽  
Radiation Dose ◽  
Iterative Reconstruction ◽  
Quality Criteria ◽  
Left Ventricular ◽  
Reconstruction Algorithms ◽  
Adaptive Statistical Iterative Reconstruction ◽  
Low Contrast ◽  
Statistical Iterative Reconstruction

Background Computed tomography (CT) technology is rapidly evolving and software solution developed to optimize image quality and/or lower radiation dose. Purpose To investigate the influence of adaptive statistical iterative reconstruction (ASIR) at different radiation doses in coronary CT angiography (CCTA) in detailed image quality. Material and Methods A total of 160 CCTA were reconstructed as follows: 55 scans with filtered back projection (FBP) (650 mA), 51 scans (455 mA) with 30% ASIR (ASIR30), and 54 scans (295 mA) with 60% ASIR (ASIR60). For each reconstruction, subjective image quality was assessed by five independent certified cardiologists using a visual grading analysis (VGA) with five predefined image quality criteria consisting of a 5-point scale. Objective measures were contrast, noise, and contrast-to-noise ratio (CNR). Results The CTDIvol resulted in 10.3 mGy, 7.4 mGy, and 4.6 mGy for FBP, ASIR30, and ASIR60, respectively. Homogeneity of the left ventricular lumen was the sole aspect in which reconstruction algorithms differed with a decreasing effect for ASIR60 compared to FBP (estimated odds ratio [OR] = 0.49 [95% confidence interval (CI) = 0.32–0.76; P = 0.001]). Decreased sharpness and spatial- and low-contrast resolutions were observed when using ASIR instead of FBP, but differences were not statistically significant. Concerning objective measurements, noise increased significantly for ASIR30 (OR = 1.08; 95% CI = 1.02–1.14; P = 0.006) and ASIR60 (OR = 1.06; 95% CI = 1.01–1.12; P = 0.034) compared to FBP. Conclusion ASIR significantly decreased the subjectively assessed homogeneity of the left ventricular lumen and increased the objectively measured noise compared to FBP. Considering these results, ASIR at a reduced radiation dose should be implemented with caution.

scholarly journals Adaptive Statistical Iterative Reconstructions Technique (ASIR) Impact on Both Image Quality and Dose in CT Chest Examination

2018 ◽  
Vol 14 (2) ◽  
pp. 5574-5585
Author(s):  
Mariam Isam ◽  
Ayman Mokhtar ◽  
A. Abdelrazek ◽  
Sabry EL Mogy ◽  
A.H. Oraby
Keyword(s):  
Computed Tomography ◽  
Image Quality ◽  
Iterative Reconstruction ◽  
Chest Ct ◽  
Filter Back Projection ◽  
Back Projection ◽  
Adaptive Statistical Iterative Reconstruction ◽  
Statistical Iterative Reconstruction ◽  
Chest Examination ◽  
Projection Techniques

The main objective of the presented study was to estimate the influence of Adaptive Statistical Iterative Reconstruction (ASIR) algorithm on image and dose Image Quality in Chest CT (Computed tomography) examination compared with the FBP (Filter back projection) techniques.

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