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21st International Conference on Artificial Intelligence and Soft Computing (ICAISC)

作者： Pluta, Piotr Czestochowa Tech Univ Dept Intelligent Comp Syst Armii Krajowej 36 PL-42200 Czestochowa Poland

ISBN: (纸本)9783031234798;9783031234804

This work is related to our original statistical model-based iterative reconstruction conception for medical computed tomography with the flying focal spot. This new reconstruction approach is based on a continuous-to-continuous data model and the forward model formulated as a shift-invariant system. The proposed reconstruction methodology resembles the single slice rebinning concept, belonging to the so-called "nutating" reconstruction algorithms. Our algorithm is classified as an iterative reconstruction method. The proposed forward model is derived as a shift-invariant system. Thanks to this fact, it is possible to use an FFT algorithm to reduce the computational complexity of the reconstruction problem. Because of this, we can obtain reconstructed images in a time comparable to that of FBP methods, which is especially important for ambulatory purposes. The performed by us computer simulations have shown that the statistical reconstruction conception presented here outperforms the referential traditional FBP method concerning the image quality obtained and can be competitive regarding the time of the reconstruction performance.

关键词： Image reconstruction from projections Computed tomography iterative reconstruction algorithm Flying focal spot

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Impact of dose reduction and iterative reconstruction algorithm on the detectability of pulmonary nodules by artificial intelligence

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DIAGNOSTIC AND INTERVENTIONAL IMAGING 2022年第5期103卷 273-280页

作者： Schwyzer, Moritz Messerli, Michael Eberhard, Matthias Skawran, Stephan Martini, Katharina Frauenfelder, Thomas Univ Hosp Zurich Inst Diagnost & Intervent Radiol CH-8091 Zurich Switzerland Swiss Fed Inst Technol Hlth Sci & Technol Inst Food Nutr & Hlth CH-8603 Schwerzenbach Switzerland Univ Zurich CH-8006 Zurich Switzerland Univ Penn Sch Engn & Appl Sci Philadelphia PA 19104 USA Univ Hosp Zurich Dept Nucl Med CH-8091 Zurich Switzerland

Purpose: The purpose of this study was to assess whether the performances of an automated software for lung nodule detection with computed tomography (CT) are affected by radiation dose and the use of iterative reconstruction algorithm. Materials and methods: A chest phantom (Multipurpose Chest Phantom N1;Kyoto Kagaku Co. Ltd, Kyoto, Japan) with 15 pulmonary nodules was scanned with a total of five CT protocol settings with up to 20-fold dose reduction. All CT examinations were reconstructed with iterative reconstruction algorithms ADMIRE 3 and ADMIRE 5 and were then analyzed for the presence of pulmonary nodules with a fully automated computer aided detection software system (InferRead (TM) CT Lung, Infervision), which is based on deep neural networks. Results: The sensitivity of fully automated pulmonary nodule detection for ground-glass nodules at standard dose CT was greater (70.0%;14/20;95% CI: 51.6-88.4%) than at 10-fold and 20-fold dose reduction (30.0%;6/20;95% CI: 0.0%-62.5%). There were less false positive findings when ADMIRE 5 reconstruction was used (4.0 +/- 2.8 [SD];range: 2-6) instead of ADMIRE 3 reconstruction (25.0 +/- 15.6 [SD];range: 14-36). There was no difference in the sensitivity of detection of solid and subsolid nodules between standard dose (100%;95% CI: 100-100%) and 10-and 20-fold reduced dose CT (92.5%;95% CI: 83.8-100.0%). Image noise was significantly greater with ADMIRE 3 (81 +/- 2 [SD] [range: 79-84];104 +/- 3 [SD] [range: 101-107];114 +/- 5 [SD] [range: 110-119];193 +/- 10 [SD] [range: 183-203];220 +/- 16 [SD] [range: 210-238]) compared to ADMIRE 5 (44 +/- 2 [SD] [range: 42-46];60 +/- 2 [SD] [range: 57-61];66 +/- 1 [SD] [range: 65-67];103 +/- 4 [SD] [range: 98-106];110 +/- 1 [SD] [range: 109-111]), respectively in each of the five CT protocols. Conclusion: This phantom study suggests that dose reduction and iterative reconstruction settings have an impact on detectability of pulmonary nodules by artificial intelligence software and

关键词： Artificial intelligence Dose reduction iterative reconstruction algorithm Lung nodule Nodule detection

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Computed Tomography Image Analysis of Neuromuscular Electrical Stimulation in the Treatment of Knee Osteoarthritis with Different Radiologic Characteristics Based on iterative reconstruction algorithm

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WORLD NEUROSURGERY 2021年 149卷 372-379页

作者： Xing, Weijin Cai, Mubin Li, Chuanzi Nie, Zhongshi Tang, Wencai Hainan Med Univ Dept Radiol Affiliated Hosp 2 Haikou Hainan Peoples R China

OBJECTIVE: To use computed tomography image analysis of iterative reconstruction algorithm to understand effect of neuromuscular electrical stimulation of quadriceps on motor function rehabilitation after total knee arthroplasty. METHODS: After total knee arthroplasty, 104 patients were randomly divided into 2 groups. The treatment group comprised 52 patients. The quadriceps femoris was stimulated by neuromuscular electrical stimulation, and patients were required to actively extend the knee along with the current stimulation. In the second group, which received cutaneous nerve electrical stimulation, 2 sets of electrodes were placed on knee pain points. All patients participated in conventional rehabilitation and were discharged from the hospital a mean 14.89 +/- 3.65 days after treatment. Visual analog scale, range of motion of knee joint, and Knee Injury and Osteoarthritis Score were evaluated before discharge. The mean interval between follow-up evaluations after discharge was 9.5 months. Knee Society Score and Knee Injury and Osteoarthritis Score were assessed during follow-up. RESULTS: Visual analog scale scores of treatment and control groups at discharge were 18.11 +/- 9.66 and 16.13 +/- 4.25, and active range of motion of the knee joint was 103.21 degrees +/- 15.44 degrees and (99.21 degrees +/- 15.19 degrees, respectively. Limitation of active knee extension in the treatment group was 1.93 degrees +/- 3.47 degrees, which was significantly smaller than in the control group (6.26 degrees +/- 4.28 degrees). CONCLUSIONS: Neuromuscular electrical stimulation of the quadriceps muscle early after total knee arthroplasty helps to improve the function of the knee extension device and accelerate functional rehabilitation. Computed tomography has found that changes in tibial subchondral bone plate and subchondral cancellous bone in patients with knee osteoarthritis are mainly due to destruction of ultrastructural homeostasis. This change may be the cause of knee oste

关键词： CT image iterative reconstruction algorithm Knee extension device Neuromuscular electrical stimulation Rehabilitation treatment Total knee arthroplasty

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Effect of iterative reconstruction algorithm levels on noise index and figure-of-merit in CT pulmonary angiography examinations

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JOURNAL OF X-RAY SCIENCE AND TECHNOLOGY 2020年第5期28卷 893-903页

作者： Harun, H. H. Karim, M. K. A. Abbas, Z. Sabarudin, A. Muniandy, S. C. Ibahim, M. J. Univ Putra Malaysia Fac Sci Dept Phys Serdang Selangor Malaysia Univ Kebangsaan Malaysia Fac Hlth Sci Dept Diagnost & Appl Hlth Sci Bangi Malaysia Hosp Kuala Lumpur Dept Radiol Jalan Pahang Kuala Lumpur Malaysia Univ Teknol MARA Fac Med Dept Biochem & Mol Med Sungai Buloh Selangor Malaysia

PURPOSE: To evaluate the influence of iterative reconstruction (IR) levels on Computed Tomography (CT) image quality and to establish Figure of Merit (FOM) value for CT Pulmonary Angiography (CTPA) examinations. METHODS: Images of 31 adult patients who underwent CTPA examinations in our institution from March to April 2019 were retrospectively collected. Other data, such as scanning parameters, radiation dose and body habitus information from the subjects were also recorded. Six different levels of IR were applied to the volume data of the subjects. Five circles of the region of interest (ROI) were drawn in five different arteries namely, pulmonary trunk, right pulmonary artery, left pulmonary artery, ascending aorta and descending aorta. The mean Signal-to-noise ratio (SNR) was obtained, and the FOM was calculated in a fraction of the SNR2 divided by volume-weighted CT dose index (CTDIvol) and SNR2 divided by the size-specific dose estimates (SSDE). RESULTS: Overall, we observed that the mean value of CTDIvol and SSDE were 13.79 +/- 7.72 mGy and 17.25 +/- 8.92 mGy, respectively. Notably, SNR values significantly increase with increase of the IR level (p < 0.05). There are also significant differences (p < 0.05) in the FOM for both SNR2/SSDE and SNR2/CTDIvol attained in different IR levels. CONCLUSION: We successfully evaluate the value of radiation dose and image quality performance and set up a figure of merit for both parameters to further verify scanning protocols by radiology personnel.

关键词： Signal-to-noise ratio figure-of-merit CT pulmonary angiography pulmonary embolism iterative reconstruction algorithm

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Statistical iterative reconstruction algorithm Based on a Continuous-to-Continuous Model Formulated for Spiral Cone-Beam CT 20th

Statistical Iterative Reconstruction Algorithm Based on a Co...

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20th Annual International Conference on Computational Science (ICCS)

作者： Cierniak, Robert Pluta, Piotr Czestochowa Tech Univ Inst Computat Intelligence Armii Krajowej 36 PL-42200 Czestochowa Poland

ISBN: (纸本)9783030504205;9783030504199

This paper is closely related to the originally formulated 3D statistical model-based iterative reconstruction algorithm for spiral cone-beam x-ray tomography. The concept proposed here is based on a continuous-to-continuous data model, and the reconstruction problem is formulated as a shift invariant system. This algorithm significantly improves the quality of the subsequently reconstructed images, so allowing a reduction in the x-ray dose absorbed by a patient. This form of reconstruction problem permits a reduction in the computational complexity in comparison with other model-based iterative approaches. Computer simulations have shown that the reconstruction method presented here outperforms standard FDK methods with regard to the image quality obtained and can be competitive in terms of time of calculation.

关键词： iterative reconstruction algorithm Computed tomography Statistical method

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Submillisievert CT angiography for carotid arteries using wide array CT scanner and latest iterative reconstruction algorithm in comparison with previous generations technologies: Feasibility and diagnostic accuracy

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JOURNAL OF CARDIOVASCULAR COMPUTED TOMOGRAPHY 2019年第3期13卷 41-47页

作者： Annoni, Andrea Daniele Montorsi, Piero Andreini, Daniele Pontone, Gianluca Mancini, Maria Elisabetta Muscogiuri, Giuseppe Formenti, Alberto Mushtaq, Saima Trabattoni, Piero Dainese, Luca Pepi, Mauro IRCCS Ctr Cardiol Monzino Via C Parea 4 I-20138 Milan Italy Univ Milan Dept Clin Sci & Community Hlth Milan Italy

Objectives: To assess evaluability and diagnostic accuracy of a low dose CT angiography (CTA) protocol for carotid arteries using latest iterative reconstruction (IR) algorithm in comparison with standard 100 kVp protocol using previous generation CT and IR. Materials and methods: 105 patients, referred for CTA of the carotid arteries were prospectively enrolled in our study and underwent CTA with 80 kVp and latest IR algorithm (group 1). Data were retrospectively compared with 100 consecutive patients with similar examination indications that had previously undergone CTA of carotid arteries with a standard 100 kVp protocol and a first generation IR algorithm (group 2). Image quality was evaluated with a 4-point Likert-scale. For each exam CT number, image noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) at level of common carotid artery (CCA), internal carotid artery (ICA) and at level of Circle of Willis and Effective Dose (ED) were evaluated. 62 Group 1 patients underwent a clinically indicated DSA and results were compared with CTA. Results: No exams reported as not diagnostic. The overall mean CT number value of all arterial segments was above 450 HU in both groups. Significant lower noise, and higher SNR and CNR values were found in group 1 in comparison with group 2 despite the use of 80 kVp. In 62-group 1 patients studied by DSA, CTA showed in a segment-based analysis a sensitivity, negative predictive value and accuracy of 100%, 100% and 99% respectively. Mean ED in group 1 was 0.54 +/- 0.1 mSv with a dose reduction up to 86%. Conclusions: CTA for carotid arteries using latest IR algorithm allows to perform exams with submillisievert radiation exposure maintaining good image quality, overall evaluability and diagnostic accuracy.

关键词： Computed tomography angiography Carotid arteries Atherosclerosis Dose reduction iterative reconstruction algorithm

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"Hyperdense artery sign" in early ischemic stroke: diagnostic value of model-based reconstruction approach in comparison with standard hybrid iterative reconstruction algorithm

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NEURORADIOLOGY 2018年第12期60卷 1273-1280页

作者： Lombardi, Sophie Riva, Luca Patassini, Mirko Remida, Paolo Capraro, Cristina Canonico, Francesco Franzesi, Cammillo Talei Ippolito, Davide San Gerardo Hosp Dept Diagnost Radiol Via Pergolesi 33 I-20900 Monza MB Italy Univ Milano Bicocca Sch Med Via Cadore 48 I-20900 Monza MB Italy

PurposeHyperdense artery sign is the earliest sign of ischemic stroke on non-enhanced computed tomography and it can be visible long before parenchymal changes. The aim of our study was to compare diagnostic value of model-based iterative reconstruction algorithm (IMR) with that of iterative reconstruction algorithm (iDose4) in identifying hyperdense artery *** selected 56 consecutive patients suspected for ischemic stroke, who underwent a NCCT and that demonstrated a vessel occlusion at angio-CT or developed ischemic lesion at follow-up CT. Two readers randomly analyzed images of NCCT reconstructed both with iDose4 (4mm) and IMR (2mm), reporting presence of hyperdense artery sign (0: no;1: yes;2: not sure). They rated image quality on a 4-point scale (1: unacceptable;4: more than average) and recorded HU values of clot and of normal vessel and measured noise index, CNR and *** values of CTDI, DLP, and ED were respectively of 43mGy, 819.7mGycm, and *** analyzing the IMR reconstruction, both readers were able to recognize hyperdense vessel sign in 55/56 patients, while only in 12/56 patients were identified with *** obtained better rating of image quality (mean score for IMR 3.32 vs 2.53 for iDose), higher clot density (57.2 vs 46.7 HU), lower noise index (5 vs 2), higher CNR and SNR (respectively 4.2 vs 2 and 16.8 vs 8.5).ConclusionsModel-based approach significantly increases sensitivity in detecting hyperdense artery sign, offering higher SNR and CNR in brain CT images in comparison with standard hybrid reconstruction algorithm.

关键词： Computed tomography Brain CT Hyperdense artery sign Brain stroke iterative reconstruction algorithm

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Noise indices adjusted to body mass index and an iterative reconstruction algorithm maintain image quality on low-dose contrast-enhanced liver CT

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JOURNAL OF X-RAY SCIENCE AND TECHNOLOGY 2017年第4期25卷 597-611页

作者： Zhao, Yongxia Suo, Hongna Wu, Yanmin Zuo, Ziwei Zhao, Sisi Cheng, Shujie Hebei Univ Affiliated Hosp 212 Yuhua East Rd Baoding 071000 Hebei Peoples R China Hebei Univ Med Sch Baoding Hebei Peoples R China

OBJECTIVES: Since body mass index (BMI) affects medical imaging quality or noise due to penetration of the radiation through bodies with varying sizes, this study aims to investigate and determine the optimal BMI-adjusted noise index (NI) setting on the contrast-enhanced liver CT scans obtained using 3D Smart mA technology with adaptive statistical iterative reconstruction (ASIR 2.0) algorithm. MATERIALS AND METHODS: A total of 320 patients who had contrast-enhanced liver CT scans were divided into two equal-sized groups: A (18.5 kg/m(2) <= BMI<24.9 kg/m(2)) and B (24.9 kg/m(2) <= BMI <= 34.9 kg/m(2)). The two groups were randomly divided into four subgroups with an NI of 11, 13, 15, and 17. All images were reconstructed with 50% ASIR 2.0. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated after the late arterial, portal venous, and equilibrium phases were completed. Images were evaluated by two radiologists using a subjective 0 - 5 scale. Mean CT dose index of volume, dose-length product, and effective dose (ED) were calculated and compared using one-way ANOVA. RESULTS: In group A, the best-quality images obtained at the lowest ED were scanned at an NI of 15 in the late arterial phase, and at an NI of 17 in the portal venous and equilibrium phases. In group B, the best results were obtained at an NI of 13 in the late arterial phase, and at an NI of 15 in the portal venous and equilibrium phases. CONCLUSION: Adjusting NI and iterative reconstruction algorithm based on body mass index can help improve image quality on contrast-enhanced liver CT scans, even at low radiation dose.

关键词： Body mass index image quality iterative reconstruction algorithm noise index radiation dose

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iterative reconstruction algorithms for solving the Schrodinger equations on conical spaces

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ANALYSIS AND MATHEMATICAL PHYSICS 2022年第1期12卷 31-31页

作者： Ndiaye, Joshua Warigue Kings Sch Dept Sci Technol & Dev Res BP 1560 Bujumbura Burundi

We consider a system of Schrodinger equations on conical spaces. We first rewrite the iterative reconstruction algorithms for two kinds of average Schrodinger functionals and prove their convergence. Then the asymptotic pointwise error estimates are presented for both algorithms under the case that the average samples are corrupted by noise.

关键词： Schrodinger equation iterative reconstruction algorithm Spectral bounds

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Dose reduction and image quality in CT examinations using an iterative reconstruction algorithm: a phantom study

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BIOMEDICAL PHYSICS & ENGINEERING EXPRESS 2015年第4期1卷

作者： Guariglia, S. Meliado, G. Zivelonghi, E. Pinali, L. Montemezzi, S. Cavedon, C. Azienda Osped Univ Integrata Verona Med Phys Unit Pie Stefani 1 I-37126 Verona Italy Azienda Osped Univ Integrata Verona Dept Radiol I-37126 Verona Italy

The purpose of this work is to evaluate the potential dose reduction in computed tomography (CT) examinations using an iterative algorithm compared to a filtered backprojection (FBP) reconstruction, analyzing image quality parameters. A 256 slice CT scanner, equipped with software for both FBP and iterative reconstruction, and a CT dedicated phantom were used. The image quality was evaluated by analyzing five different parameters: CT number constancy, signal to noise ratio (SNR), contrast to noise ratio (CNR), non-uniformity and axial spatial resolution (modulation transfer function, MTF). The CNR was evaluated on a low contrast insert and on a high contrast teflon insert, while the MTF was evaluated on a high density bead. The analysis was performed both on images obtained with FBP reconstruction and with the iterative algorithm (level 1 to 6). CT numbers were consistent between standard FBP and the iterative reconstruction. Non-uniformity and spatial resolution were not affected by the use of the iterative algorithm, and the SNR and the CNR were improved with the iterative algorithm, as a function of the level of iteration used. Comparing FBP to the sixth level of iteration, in a 120 kV scan performed at 200 mAs, a mean 43.6% noise reduction was observed and for the SNR and the CNR, a mean improvement of 70.9% and 70.6%, respectively, was obtained. A mean dose reduction of 36.5% was estimated using iterative reconstruction at level 3 without loss of image quality. The use of the iterative reconstruction method offers the possibility to improve image quality or to reduce patient dose in CT examinations, or a combination of these aspects. In our experience, reducing the tube current by 30% compared to the FBP scan and reconstructing the images by means of the iterative algorithm (level 3) resulted in equivalent image quality for both methods.

关键词： CT iterative reconstruction algorithm dose reduction

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