scholarly journals Computed tomography-based calcium scoring in cadaver leg arteries: influence of dose, reader, and reconstruction algorithm

2021 ◽  
pp. 110080
Author(s):  
Daan J. de Jong ◽  
Simone van der Star ◽  
Ronald L. A. W. Bleys ◽  
Arnold M. R. Schilham ◽  
Hugo J. Kuijf ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Reconstruction Algorithm ◽  
Calcium Scoring

scholarly journals Manual kidney stone size measurements in computed tomography are most accurate using multiplanar image reformatations and bone window settings

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Robert Peter Reimer ◽  
Konstantin Klein ◽  
Miriam Rinneburger ◽  
David Zopfs ◽  
Simon Lennartz ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Treatment Decision ◽  
Reconstruction Algorithm ◽  
Slice Thickness ◽  
Reconstruction Algorithms ◽  
Stone Size ◽  
Bone Window ◽  
3D Printed ◽  
Measurement Strategies ◽  
Digital Caliper

AbstractComputed tomography in suspected urolithiasis provides information about the presence, location and size of stones. Particularly stone size is a key parameter in treatment decision; however, data on impact of reformatation and measurement strategies is sparse. This study aimed to investigate the influence of different image reformatations, slice thicknesses and window settings on stone size measurements. Reference stone sizes of 47 kidney stones representative for clinically encountered compositions were measured manually using a digital caliper (Man-M). Afterwards stones were placed in a 3D-printed, semi-anthropomorphic phantom, and scanned using a low dose protocol (CTDIvol 2 mGy). Images were reconstructed using hybrid-iterative and model-based iterative reconstruction algorithms (HIR, MBIR) with different slice thicknesses. Two independent readers measured largest stone diameter on axial (2 mm and 5 mm) and multiplanar reformatations (based upon 0.67 mm reconstructions) using different window settings (soft-tissue and bone). Statistics were conducted using ANOVA ± correction for multiple comparisons. Overall stone size in CT was underestimated compared to Man-M (8.8 ± 2.9 vs. 7.7 ± 2.7 mm, p < 0.05), yet closely correlated (r = 0.70). Reconstruction algorithm and slice thickness did not significantly impact measurements (p > 0.05), while image reformatations and window settings did (p < 0.05). CT measurements using multiplanar reformatation with a bone window setting showed closest agreement with Man-M (8.7 ± 3.1 vs. 8.8 ± 2.9 mm, p < 0.05, r = 0.83). Manual CT-based stone size measurements are most accurate using multiplanar image reformatation with a bone window setting, while measurements on axial planes with different slice thicknesses underestimate true stone size. Therefore, this procedure is recommended when impacting treatment decision.

Electron-Beam Computed Tomography for Symptomatic Coronary Disease

2000 ◽  
Vol 8 (1) ◽  
pp. 46-49
Author(s):  
Bernard Kwok Wing Kuin ◽  
Yean Teng Lim ◽  
Swee Tian Quek ◽  
Lenny Tan Kheng Ann
Keyword(s):  
Computed Tomography ◽  
Electron Beam ◽  
Coronary Artery ◽  
Coronary Disease ◽  
Coronary Artery Calcium Score ◽  
Calcium Score ◽  
High Specificity ◽  
Calcium Scoring ◽  
Electron Beam Computed Tomography ◽  
Low Sensitivity

Forty-two symptomatic patients underwent both electron-beam computed tomo-graphic calcium scoring and coronary angiography. Correlation between coronary artery calcium score and angiographic coronary disease showed a high specificity (90%) but low sensitivity (50%). The low negative predictive value of 36% suggests that electron-beam computed tomography is not useful in symptomatic patients.

scholarly journals Combining Acceleration Techniques for Low-Dose X-Ray Cone Beam Computed Tomography Image Reconstruction

2017 ◽  
Vol 2017 ◽  
pp. 1-10
Author(s):  
Hsuan-Ming Huang ◽  
Ing-Tsung Hsiao
Keyword(s):  
Computed Tomography ◽  
Image Reconstruction ◽  
Low Dose ◽  
Computational Cost ◽  
Reconstruction Algorithm ◽  
Reconstruction Algorithms ◽  
Acceleration Techniques ◽  
Reconstruction Methods ◽  
Speed Up ◽  
Phantom Studies

Background and Objective. Over the past decade, image quality in low-dose computed tomography has been greatly improved by various compressive sensing- (CS-) based reconstruction methods. However, these methods have some disadvantages including high computational cost and slow convergence rate. Many different speed-up techniques for CS-based reconstruction algorithms have been developed. The purpose of this paper is to propose a fast reconstruction framework that combines a CS-based reconstruction algorithm with several speed-up techniques.Methods. First, total difference minimization (TDM) was implemented using the soft-threshold filtering (STF). Second, we combined TDM-STF with the ordered subsets transmission (OSTR) algorithm for accelerating the convergence. To further speed up the convergence of the proposed method, we applied the power factor and the fast iterative shrinkage thresholding algorithm to OSTR and TDM-STF, respectively.Results. Results obtained from simulation and phantom studies showed that many speed-up techniques could be combined to greatly improve the convergence speed of a CS-based reconstruction algorithm. More importantly, the increased computation time (≤10%) was minor as compared to the acceleration provided by the proposed method.Conclusions. In this paper, we have presented a CS-based reconstruction framework that combines several acceleration techniques. Both simulation and phantom studies provide evidence that the proposed method has the potential to satisfy the requirement of fast image reconstruction in practical CT.

scholarly journals Numerical and Experimental Investigation of Computed Tomography of Chemiluminescence for Hydrogen-Air Premixed Laminar Flames

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Liang Lv ◽  
Jianguo Tan ◽  
Yue Hu
Keyword(s):  
Computed Tomography ◽  
Cone Angle ◽  
Reconstruction Algorithm ◽  
Laminar Flames ◽  
Iccd Camera ◽  
Critical Cone ◽  
Premixed Laminar Flames ◽  
Flame Structures ◽  
Premixed Laminar ◽  
Flow Velocities

Computed tomography of chemiluminescence (CTC) is a promising technique for combustion diagnostics, providing instantaneous 3D information of flame structures, especially in harsh circumstance. This work focuses on assessing the feasibility of CTC and investigating structures of hydrogen-air premixed laminar flames using CTC. A numerical phantom study was performed to assess the accuracy of the reconstruction algorithm. A well-designed burner was used to generate stable hydrogen-air premixed laminar flames. TheOH⁎chemiluminescence intensity field reconstructed from 37 views using CTC was compared to theOH⁎chemiluminescence distributions recorded directly by a single ICCD camera from the side view. The flame structures in different flow velocities and equivalence ratios were analyzed using the reconstructions. The results show that the CTC technique can effectively indicate real distributions of the flame chemiluminescence. The height of the flame becomes larger with increasing flow velocities, whereas it decreases with increasing equivalence ratios (no larger than 1). The increasing flow velocities gradually lift the flame reaction zones. A critical cone angle of 4.76 degrees is obtained to avoid blow-off. These results set up a foundation for next studies and the methods can be further developed to reconstruct 3D structures of flames.

A reconstruction algorithm for coherent scatter computed tomography based on filtered back-projection

2003 ◽  
Vol 30 (9) ◽  
pp. 2465-2474 ◽  
Author(s):  
U. van Stevendaal ◽  
J.-P. Schlomka ◽  
A. Harding ◽  
M. Grass
Keyword(s):  
Computed Tomography ◽  
Reconstruction Algorithm ◽  
Back Projection ◽  
Filtered Back Projection ◽  
Coherent Scatter

Abstract 2759: Elevated Coronary Calcium Scores Measured by Multi-Slice Computed Tomography are Associated with Low Response to Clopidogrel in Patients with Stable Angina pectoris

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Christof Burgstahler ◽  
Tobias Geisler ◽  
Stephan Lindemann ◽  
Anja Reimann ◽  
Harald Brodoefel ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Stent Placement ◽  
Calcium Score ◽  
Significant Negative Correlation ◽  
Coronary Calcium ◽  
Plaque Burden ◽  
Agatston Score ◽  
Calcium Scoring ◽  
Coronary Calcium Scoring ◽  
High Calcium

Cardiac multi-detector computed tomography (MDCT) with retrospective ECG-gating permits the determination and quantification of coronary calcifications. High calcium scores are known to be associated with elevated all-cause mortality. Moreover, low response to clopidogrel influences cardiovascular outcome after coronary stent placement. We sought to evaluate whether elevated calcium scores are associated with a low response to clopidogrel. Methods 62 patients were enrolled in this trial (52 male, mean age 64.8 ± 8.9 years). Coronary calcium scoring (expressed as Agatston score equivalent, ASE) was measured with multi-slice computed tomography (Sensation 64™ [n=19] and Somatom Definition ™ [n=43], Siemens, Forchheim, Germany) prior to stent implantation. Responsiveness to clopidogrel was assessed by ADP (20 micromol/L)-induced aggregometry at least 6 h after administration of a loading dose of 600 mg clopidogrel. Results Median calcium score was 736 ASE [range 0 –3126] and mean platelet inhibition was 35±19% [range 0 –70]. There was a significant negative correlation between ASE and response to clopidogrel (r 2 =0.135, p=0.0033, slope 7.809 ± 2.549). Patients within the first quartile of ASE had significantly better response to clopidogrel than other patients (p<0.05). Establishing a threshold of 200 ASE responsiveness to clopidogrel could be predicted with a positive predictive value of 80% and a specificity of 91%. Conclusions We could demonstrate that elevated ASE is associated with a low response to clopidogrel. Patients with a low coronary plaque burden are more likely to have a good response to clopidogrel. Coronary calcium scoring might help to identify low responders to clopidogrel prior to stent placement and aggregometry.

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