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Alhajeri A, Aremu O, Almutahhar M, Yousif M, Albinmousa J, Ali U. On the effect of loading and printing parameters that influence the fatigue behavior of laser powder-bed fusion additively manufactured steels. Heliyon 2024; 10:e29229. [PMID: 38707403 PMCID: PMC11066603 DOI: 10.1016/j.heliyon.2024.e29229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 04/01/2024] [Accepted: 04/03/2024] [Indexed: 05/07/2024] Open
Abstract
The aim of this paper is to investigate the factors (build orientation, sample conditions, and R-ratio) that affect the cyclic response of laser powder-bed fusion stainless steel 316L and 17-4 PH parts. Initially, the data set was analyzed to confirm the normality assumption. The significant and insignificant factors that affect the fatigue life were identified using analysis of variance (ANOVA). Main effects for different sample conditions were also analyzed. Process and reproducibility assessment were performed to study the effect of process factors. Combining fatigue data sets was recommended as the best approach to accurately predict the fatigue behavior of LPBF 316L and 17-4 PH parts. Finally, the effect of sample conditions on fatigue life was quantified. The highest fatigue life was achieved with Machined-Polished surfaces.
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Affiliation(s)
- Ali Alhajeri
- Department of Mechanical Engineering, King Fahd University of Petroleum & Minerals, Dhahran, 31261, Saudi Arabia
| | - Oluwatobi Aremu
- Department of Mechanical Engineering, King Fahd University of Petroleum & Minerals, Dhahran, 31261, Saudi Arabia
| | - Mosa Almutahhar
- Department of Mechanical Engineering, King Fahd University of Petroleum & Minerals, Dhahran, 31261, Saudi Arabia
| | - Mohammed Yousif
- Department of Mechanical Engineering, King Fahd University of Petroleum & Minerals, Dhahran, 31261, Saudi Arabia
| | - Jafar Albinmousa
- Department of Mechanical Engineering, King Fahd University of Petroleum & Minerals, Dhahran, 31261, Saudi Arabia
- Interdisciplinary Research Center on Advanced Materials, King Fahd University of Petroleum & Minerals, Dhahran, 31261, Saudi Arabia
| | - Usman Ali
- Department of Mechanical Engineering, King Fahd University of Petroleum & Minerals, Dhahran, 31261, Saudi Arabia
- Interdisciplinary Research Center on Advanced Materials, King Fahd University of Petroleum & Minerals, Dhahran, 31261, Saudi Arabia
- K.A. CARE Energy Research & Innovation Center at Dhahran, Saudi Arabia
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Kuzmanović D, Banko J, Skok G. Improving the operational forecasts of outdoor Universal Thermal Climate Index with post-processing. Int J Biometeorol 2024; 68:965-977. [PMID: 38441666 DOI: 10.1007/s00484-024-02640-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2023] [Revised: 02/02/2024] [Accepted: 02/13/2024] [Indexed: 04/30/2024]
Abstract
The Universal Thermal Climate Index (UTCI) is a thermal comfort index that describes how the human body experiences ambient conditions. It has units of temperature and considers physiological aspects of the human body. It takes into account the effect of air temperature, humidity, wind, radiation, and clothes. It is increasingly used in many countries as a measure of thermal comfort for outdoor conditions, and its value is calculated as part of the operational meteorological forecast. At the same time, forecasts of outdoor UTCI tend to have a relatively large error caused by the error of meteorological forecasts. In Slovenia, there is a relatively dense network of meteorological stations. Crucially, at these stations, global solar radiation measurements are performed continuously, which makes estimating the actual value of the UTCI more accurate compared to the situation where no radiation measurements are available. We used seven years of measurements in hourly resolution from 42 stations to first verify the operational UTCI forecast for the first forecast day and, secondly, to try to improve the forecast via post-processing. We used two machine-learning methods, linear regression, and neural networks. Both methods have successfully reduced the error in the operational UTCI forecasts. Both methods reduced the daily mean error from about 2.6∘ C to almost zero, while the daily mean absolute error decreased from 5∘ C to 3∘ C for the neural network and 3.5∘ C for linear regression. Both methods, especially the neural network, also substantially reduced the dependence of the error on the time of the day.
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Affiliation(s)
- Danijela Kuzmanović
- Faculty of Mathematics and Physics, University of Ljubljana, Jadranska Cesta 19, Ljubljana, 1000, Slovenia
| | - Jana Banko
- Slovenian Environment Agency, Vojkova 1b, Ljubljana, 1000, Slovenia
| | - Gregor Skok
- Faculty of Mathematics and Physics, University of Ljubljana, Jadranska Cesta 19, Ljubljana, 1000, Slovenia.
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Mahmoudi S, Gruenewald LD, Koch V, Bernatz S, Martin SS, Engelskirchen L, Radic I, Bucolo G, D'Angelo T, Gotta J, Mader C, Dos Santos DP, Scholtz JE, Gruber-Rouh T, Eichler K, Vogl TJ, Booz C, Yel I. Potential of Dual-Energy CT-Based Collagen Maps for the Assessment of Disk Degeneration in the Lumbar Spine. Acad Radiol 2024:S1076-6332(24)00127-2. [PMID: 38519304 DOI: 10.1016/j.acra.2024.02.036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Revised: 02/16/2024] [Accepted: 02/23/2024] [Indexed: 03/24/2024]
Abstract
RATIONALE AND OBJECTIVES Lumbar disk degeneration is a common condition contributing significantly to back pain. The objective of the study was to evaluate the potential of dual-energy CT (DECT)-derived collagen maps for the assessment of lumbar disk degeneration. PATIENTS AND METHODS We conducted a retrospective analysis of 127 patients who underwent dual-source DECT and MRI of the lumbar spine between 07/2019 and 10/2022. The level of lumbar disk degeneration was categorized by three radiologists as follows: no/mild (Pfirrmann 1&2), moderate (Pfirrmann 3&4), and severe (Pfirrmann 5). Recall (sensitivity) and accuracy of DECT collagen maps were calculated. Intraclass correlation coefficient (ICC) was used to evaluate inter-reader reliability. Subjective evaluations were performed using 5-point Likert scales for diagnostic confidence and image quality. RESULTS We evaluated a total of 762 intervertebral disks from 127 patients (median age, 69.7 (range, 23.0-93.7), female, 56). MRI identified 230 non/mildly degenerated disks (30.2%), 484 moderately degenerated disks (63.5%), and 48 severely degenerated disks (6.3%). DECT collagen maps yielded an overall accuracy of 85.5% (1955/2286). Recall (sensitivity) was 79.3% (547/690) for the detection of no/mild lumbar disk degeneration, 88.7% (1288/1452) for the detection of moderate disk degeneration, and 83.3% (120/144) for the detection of severe disk degeneration (ICC=0.9). Subjective evaluations of DECT collagen maps showed high diagnostic confidence (median 4) and good image quality (median 4). CONCLUSION The use of DECT collagen maps to distinguish different stages of lumbar disk degeneration may have clinical significance in the early diagnosis of disk-related pathologies in patients with contraindications for MRI or in cases of unavailability of MRI.
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Affiliation(s)
- Scherwin Mahmoudi
- Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Goethe University Frankfurt am Main, Frankfurt am Main, Germany.
| | - Leon D Gruenewald
- Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Goethe University Frankfurt am Main, Frankfurt am Main, Germany
| | - Vitali Koch
- Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Goethe University Frankfurt am Main, Frankfurt am Main, Germany
| | - Simon Bernatz
- Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Goethe University Frankfurt am Main, Frankfurt am Main, Germany; Dr. Senckenberg Institute for Pathology, University Hospital Frankfurt, Goethe University Frankfurt am Main, Frankfurt am Main, Germany
| | - Simon S Martin
- Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Goethe University Frankfurt am Main, Frankfurt am Main, Germany
| | - Lara Engelskirchen
- Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Goethe University Frankfurt am Main, Frankfurt am Main, Germany
| | - Ivana Radic
- Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Goethe University Frankfurt am Main, Frankfurt am Main, Germany
| | - Giuseppe Bucolo
- Department of Biomedical Sciences and Morphological and Functional Imaging, University of Messina, Messina, Italy
| | - Tommaso D'Angelo
- Department of Biomedical Sciences and Morphological and Functional Imaging, University of Messina, Messina, Italy
| | - Jennifer Gotta
- Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Goethe University Frankfurt am Main, Frankfurt am Main, Germany
| | - Christoph Mader
- Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Goethe University Frankfurt am Main, Frankfurt am Main, Germany
| | - Daniel Pinto Dos Santos
- Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Goethe University Frankfurt am Main, Frankfurt am Main, Germany; Department of Diagnostic and Interventional Radiology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Jan-Erik Scholtz
- Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Goethe University Frankfurt am Main, Frankfurt am Main, Germany
| | - Tatjana Gruber-Rouh
- Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Goethe University Frankfurt am Main, Frankfurt am Main, Germany
| | - Katrin Eichler
- Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Goethe University Frankfurt am Main, Frankfurt am Main, Germany
| | - Thomas J Vogl
- Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Goethe University Frankfurt am Main, Frankfurt am Main, Germany
| | - Christian Booz
- Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Goethe University Frankfurt am Main, Frankfurt am Main, Germany
| | - Ibrahim Yel
- Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Goethe University Frankfurt am Main, Frankfurt am Main, Germany
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Ramlee MH, Ammarullah MI, Mohd Sukri NS, Faidzul Hassan NS, Baharuddin MH, Abdul Kadir MR. Investigation on three-dimensional printed prosthetics leg sockets coated with different reinforcement materials: analysis on mechanical strength and microstructural. Sci Rep 2024; 14:6842. [PMID: 38514731 PMCID: PMC10958049 DOI: 10.1038/s41598-024-57454-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Accepted: 03/18/2024] [Indexed: 03/23/2024] Open
Abstract
Previous research has primarily focused on pre-processing parameters such as design, material selection, and printing techniques to improve the strength of 3D-printed prosthetic leg sockets. However, these methods fail to address the major challenges that arise post-printing, namely failures at the distal end of the socket and susceptibility to shear failure. Addressing this gap, the study aims to enhance the mechanical properties of 3D-printed prosthetic leg sockets through post-processing techniques. Fifteen PLA + prosthetic leg sockets are fabricated and reinforced with four materials: carbon fiber, carbon-Kevlar fiber, fiberglass, and cement. Mechanical and microstructural properties of the sockets are evaluated through axial compression testing and scanning electron microscopy (SEM). Results highlight superior attributes of cement-reinforced sockets, exhibiting significantly higher yield strength (up to 89.57% more than counterparts) and higher Young's modulus (up to 76.15% greater). SEM reveals correlations between microstructural properties and socket strength. These findings deepen the comprehension of 3D-printed prosthetic leg socket post-processing, presenting optimization prospects. Future research can focus on refining fabrication techniques, exploring alternative reinforcement materials, and investigating the long-term durability and functionality of post-processed 3D-printed prosthetic leg sockets.
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Affiliation(s)
- Muhammad Hanif Ramlee
- Bone Biomechanics Laboratory (BBL), Department of Biomedical Engineering and Health Sciences, Faculty of Electrical Engineering, Universiti Teknologi Malaysia, Johor Bahru 81310, Johor, Malaysia.
- Bioinspired Devices and Tissue Engineering (BIOINSPIRA) Research Group, Universiti Teknologi Malaysia, Johor Bahru 81310, Johor, Malaysia.
| | - Muhammad Imam Ammarullah
- Department of Mechanical Engineering, Faculty of Engineering, Universitas Diponegoro, Semarang, 50275, Central Java, Indonesia.
- Undip Biomechanics Engineering and Research Centre (UBM-ERC), Universitas Diponegoro, Semarang, 50275, Central Java, Indonesia.
- Department of Mechanical Engineering, Faculty of Engineering, Universitas Pasundan, Bandung, 40153, West Java, Indonesia.
- Biomechanics and Biomedics Engineering Research Centre, Universitas Pasundan, Bandung, 40153, West Java, Indonesia.
| | - Nurelisya Suraya Mohd Sukri
- Bone Biomechanics Laboratory (BBL), Department of Biomedical Engineering and Health Sciences, Faculty of Electrical Engineering, Universiti Teknologi Malaysia, Johor Bahru 81310, Johor, Malaysia
| | - Nur Syafiqah Faidzul Hassan
- Bone Biomechanics Laboratory (BBL), Department of Biomedical Engineering and Health Sciences, Faculty of Electrical Engineering, Universiti Teknologi Malaysia, Johor Bahru 81310, Johor, Malaysia
| | - Muhammad Hanif Baharuddin
- Bone Biomechanics Laboratory (BBL), Department of Biomedical Engineering and Health Sciences, Faculty of Electrical Engineering, Universiti Teknologi Malaysia, Johor Bahru 81310, Johor, Malaysia
| | - Mohammed Rafiq Abdul Kadir
- Department of Biomedical Engineering, Faculty of Engineering, Universiti Malaya, 50603, Kuala Lumpur, Federal Territory of Kuala Lumpur, Malaysia
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Esmaeili A, Rahimi A, Abbasi A, Hasannejad-Asl B, Bagheri-Mohammadi S, Farjami M, Keshel SH. Processing and post-processing of fish skin as a novel material in tissue engineering. Tissue Cell 2023; 85:102238. [PMID: 37832248 DOI: 10.1016/j.tice.2023.102238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 10/05/2023] [Accepted: 10/06/2023] [Indexed: 10/15/2023]
Abstract
As a natural material, fish skin contains significant amounts of collagen I and III, and due to its biocompatible nature, it can be used to regenerate various tissues and organs. To use fish skin, it is necessary to perform the decellularization process to avoid the immunological response of the host body. In the process of decellularization, it is crucial to conserve the extracellular matrix (ECM) three-dimensional (3D) structure. However, it is known that decellularization methods may also damage ECM strands arrangement and structure. Moreover, after decellularization, the post-processing of fish skin improves its mechanical and biological properties and preserves its 3D design and strength. Also, sterilization, which is one of the post-processing steps, is mandatory in pre-clinical and clinical settings. In this review paper, the fish skin decellularization methods performed and the various post-processes used to increase the performance of the skin have been studied. Moreover, multiple applications of acellular fish skin (AFS) and its extracted collagen have been reviewed.
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Affiliation(s)
- Ali Esmaeili
- Student Research Committee, Department of Tissue Engineering and Applied Cell Sciences, School of Advanced Technologies in Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Azam Rahimi
- Department of Tissue Engineering and Applied Cell Sciences, School of Advanced Technologies in Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Amin Abbasi
- Department of Food Science and Technology, National Nutrition and Food Technology Research Institute, Faculty of Nutrition Science and Food Technology, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Behnam Hasannejad-Asl
- Department of Biotechnology, School of Advanced Technologies in Medicine, Shahid Beheshti, University of Medical Sciences, Tehran, Iran
| | - Saeid Bagheri-Mohammadi
- Department of Physiology and Neurophysiology Research Center, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mohammad Farjami
- Department of Biostatistics, Faculty of Paramedical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Saeed Heidari Keshel
- Student Research Committee, Department of Tissue Engineering and Applied Cell Sciences, School of Advanced Technologies in Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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Urbach H, Scheiwe C, Shah MJ, Nakagawa JM, Heers M, San Antonio-Arce MV, Altenmueller DM, Schulze-Bonhage A, Huppertz HJ, Demerath T, Doostkam S. Diagnostic Accuracy of Epilepsy-dedicated MRI with Post-processing. Clin Neuroradiol 2023; 33:709-719. [PMID: 36856785 PMCID: PMC10449992 DOI: 10.1007/s00062-023-01265-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Accepted: 01/17/2023] [Indexed: 03/02/2023]
Abstract
PURPOSE To evaluate the diagnostic accuracy of epilepsy-dedicated 3 Tesla MRI including post-processing by correlating MRI, histopathology, and postsurgical seizure outcomes. METHODS 3 Tesla-MRI including a magnetization-prepared two rapid acquisition gradient echo (MP2RAGE) sequence for post-processing using the morphometric analysis program MAP was acquired in 116 consecutive patients with drug-resistant focal epilepsy undergoing resection surgery. The MRI, histopathology reports and postsurgical seizure outcomes were recorded from the patient's charts. RESULTS The MRI and histopathology were concordant in 101 and discordant in 15 patients, 3 no hippocampal sclerosis/gliosis only lesions were missed on MRI and 1 of 28 focal cortical dysplasia (FCD) type II associated with a glial scar was considered a glial scar only on MRI. In another five patients, MRI was suggestive of FCD, the histopathology was uneventful but patients were seizure-free following surgery. The MRI and histopathology were concordant in 20 of 21 glioneuronal tumors, 6 cavernomas, and 7 glial scars. Histopathology was negative in 10 patients with temporal lobe epilepsy, 4 of them had anteroinferior meningoencephaloceles. Engel class IA outcome was reached in 71% of patients. CONCLUSION The proposed MRI protocol is highly accurate. No hippocampal sclerosis/gliosis only lesions are typically MRI negative. Small MRI positive FCD can be histopathologically missed, most likely due to sampling errors resulting from insufficient harvesting of tissue.
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Affiliation(s)
- Horst Urbach
- Dept. of Neuroradiology, Medical Center, University of Freiburg, Breisacher Str. 64, 79106, Freiburg, Germany.
| | - Christian Scheiwe
- Dept. of Neurosurgery, Medical Center, University of Freiburg, Freiburg, Germany
| | - Muskesh J Shah
- Dept. of Neurosurgery, Medical Center, University of Freiburg, Freiburg, Germany
| | - Julia M Nakagawa
- Dept. of Neurosurgery, Medical Center, University of Freiburg, Freiburg, Germany
| | - Marcel Heers
- Dept. of Epileptology, Medical Center, University of Freiburg, Freiburg, Germany
| | | | | | | | | | - Theo Demerath
- Dept. of Neuroradiology, Medical Center, University of Freiburg, Breisacher Str. 64, 79106, Freiburg, Germany
| | - Soroush Doostkam
- Dept. of Neuropathology, Medical Center, University of Freiburg, Freiburg, Germany
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Gröschel J, Trauzeddel RF, Müller M, von Knobelsdorff-Brenkenhoff F, Viezzer D, Hadler T, Blaszczyk E, Daud E, Schulz-Menger J. Multi-site comparison of parametric T1 and T2 mapping: healthy travelling volunteers in the Berlin research network for cardiovascular magnetic resonance (BER-CMR). J Cardiovasc Magn Reson 2023; 25:47. [PMID: 37574535 PMCID: PMC10424349 DOI: 10.1186/s12968-023-00954-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Accepted: 07/10/2023] [Indexed: 08/15/2023] Open
Abstract
BACKGROUND Parametric mapping sequences in cardiovascular magnetic resonance (CMR) allow for non-invasive myocardial tissue characterization. However quantitative myocardial mapping is still limited by the need for local reference values. Confounders, such as field strength, vendors and sequences, make intersite comparisons challenging. This exploratory study aims to assess whether multi-site studies that control confounding factors provide first insights whether parametric mapping values are within pre-defined tolerance ranges across scanners and sites. METHODS A cohort of 20 healthy travelling volunteers was prospectively scanned at three sites with a 3 T scanner from the same vendor using the same scanning protocol and acquisition scheme. A Modified Look-Locker inversion recovery sequence (MOLLI) for T1 and a fast low-angle shot sequence (FLASH) for T2 were used. At one site a scan-rescan was performed to assess the intra-scanner reproducibility. All acquired T1- and T2-mappings were analyzed in a core laboratory using the same post-processing approach and software. RESULTS After exclusion of one volunteer due to an accidentally diagnosed cardiac disease, T1- and T2-maps of 19 volunteers showed no significant differences between the 3 T sites (mean ± SD [95% confidence interval] for global T1 in ms: site I: 1207 ± 32 [1192-1222]; site II: 1207 ± 40 [1184-1225]; site III: 1219 ± 26 [1207-1232]; p = 0.067; for global T2 in ms: site I: 40 ± 2 [39-41]; site II: 40 ± 1 [39-41]; site III 39 ± 2 [39-41]; p = 0.543). CONCLUSION Parametric mapping results displayed initial hints at a sufficient similarity between sites when confounders, such as field strength, vendor diversity, acquisition schemes and post-processing analysis are harmonized. This finding needs to be confirmed in a powered clinical trial. Trial registration ISRCTN14627679 (retrospectively registered).
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Affiliation(s)
- Jan Gröschel
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität Zu Berlin, ECRC Experimental and Clinical Research Center, Lindenberger Weg 80, 13125, Berlin, Germany
- Working Group On Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a joint cooperation between Charité Medical Faculty and the Max-Delbrück Center for Molecular Medicine, Lindenberger Weg 80, 13125, Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Berlin, Berlin, Germany
| | - Ralf-Felix Trauzeddel
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität Zu Berlin, ECRC Experimental and Clinical Research Center, Lindenberger Weg 80, 13125, Berlin, Germany
- Working Group On Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a joint cooperation between Charité Medical Faculty and the Max-Delbrück Center for Molecular Medicine, Lindenberger Weg 80, 13125, Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Berlin, Berlin, Germany
- Department of Anaesthesiology and Intensive Care Medicine, Campus Benjamin Franklin, Charité, Universitätsmedizin Berlin, corporate member of Freie Universität Berlin Und Humboldt-Universität Zu Berlin, Berlin, Germany
| | - Maximilian Müller
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität Zu Berlin, ECRC Experimental and Clinical Research Center, Lindenberger Weg 80, 13125, Berlin, Germany
- Working Group On Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a joint cooperation between Charité Medical Faculty and the Max-Delbrück Center for Molecular Medicine, Lindenberger Weg 80, 13125, Berlin, Germany
| | - Florian von Knobelsdorff-Brenkenhoff
- Working Group On Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a joint cooperation between Charité Medical Faculty and the Max-Delbrück Center for Molecular Medicine, Lindenberger Weg 80, 13125, Berlin, Germany
- KIZ, Kardiologie im Zentrum, Eisenmannstr. 4, 80331, Munich, Deutschland
| | - Darian Viezzer
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität Zu Berlin, ECRC Experimental and Clinical Research Center, Lindenberger Weg 80, 13125, Berlin, Germany
- Working Group On Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a joint cooperation between Charité Medical Faculty and the Max-Delbrück Center for Molecular Medicine, Lindenberger Weg 80, 13125, Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Berlin, Berlin, Germany
| | - Thomas Hadler
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität Zu Berlin, ECRC Experimental and Clinical Research Center, Lindenberger Weg 80, 13125, Berlin, Germany
- Working Group On Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a joint cooperation between Charité Medical Faculty and the Max-Delbrück Center for Molecular Medicine, Lindenberger Weg 80, 13125, Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Berlin, Berlin, Germany
| | - Edyta Blaszczyk
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität Zu Berlin, ECRC Experimental and Clinical Research Center, Lindenberger Weg 80, 13125, Berlin, Germany
- Working Group On Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a joint cooperation between Charité Medical Faculty and the Max-Delbrück Center for Molecular Medicine, Lindenberger Weg 80, 13125, Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Berlin, Berlin, Germany
| | - Elias Daud
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität Zu Berlin, ECRC Experimental and Clinical Research Center, Lindenberger Weg 80, 13125, Berlin, Germany
- Working Group On Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a joint cooperation between Charité Medical Faculty and the Max-Delbrück Center for Molecular Medicine, Lindenberger Weg 80, 13125, Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Berlin, Berlin, Germany
- The Cardiology Department, Galilee Medical Center, Azrieli Faculty of Medicine Bar-Ilan University, Nahariya, Safed, Israel
| | - Jeanette Schulz-Menger
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität Zu Berlin, ECRC Experimental and Clinical Research Center, Lindenberger Weg 80, 13125, Berlin, Germany.
- Working Group On Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a joint cooperation between Charité Medical Faculty and the Max-Delbrück Center for Molecular Medicine, Lindenberger Weg 80, 13125, Berlin, Germany.
- DZHK (German Centre for Cardiovascular Research), Partner Site Berlin, Berlin, Germany.
- Department of Cardiology and Nephrology, HELIOS Hospital Berlin-Buch, Berlin, Germany.
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Oh R, Lim JH, Lee CG, Lee KW, Kim SY, Kim JE. Effects of washing solution temperature on the biocompatibility and mechanical properties of 3D-Printed dental resin material. J Mech Behav Biomed Mater 2023; 143:105906. [PMID: 37178635 DOI: 10.1016/j.jmbbm.2023.105906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 05/07/2023] [Accepted: 05/08/2023] [Indexed: 05/15/2023]
Abstract
The use of digital manufacturing, particularly additive manufacturing using three-dimensional (3D) printing, is expanding in the field of dentistry. 3D-printed resin appliances must undergo an essential process, post-washing, to remove residual monomers; however, the effect of the washing solution temperature on the biocompatibility and mechanical properties remains unclear. Therefore, we processed 3D-printed resin samples under different post-washing temperatures (without temperature control (N/T), 30 °C, 40 °C, and 50 °C) for different durations (5, 10, 15, 30, and 60 min) and evaluated the degree of conversion rate, cell viability, flexural strength, and Vickers hardness. Increasing the washing solution temperature significantly improved the degree of conversion rate and cell viability. Conversely, increasing the solution temperature and time decreased the flexural strength and microhardness. This study confirmed that the washing temperature and time influence the mechanical and biological properties of the 3D-printed resin. Washing 3D-printed resin at 30 °C for 30 min was most efficient to maintain optimal biocompatibility and minimize changes of mechanical properties.
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Affiliation(s)
- Rojee Oh
- Dental Hospital, Veterans Health Service Medical Center, Seoul, 05368, Republic of Korea; Department of Prosthodontics, Yonsei University College of Dentistry, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Jung-Hwa Lim
- Department of Prosthodontics, Yonsei University College of Dentistry, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Chan-Gyu Lee
- Department of Prosthodontics, Yonsei University College of Dentistry, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea; Oral Science Research Center, Yonsei University College of Dentistry, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Keun-Woo Lee
- Dental Hospital, Veterans Health Service Medical Center, Seoul, 05368, Republic of Korea; Department of Prosthodontics, Yonsei University College of Dentistry, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Sung-Yong Kim
- Dental Hospital, Veterans Health Service Medical Center, Seoul, 05368, Republic of Korea.
| | - Jong-Eun Kim
- Department of Prosthodontics, Yonsei University College of Dentistry, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea.
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9
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Papageorgakis C, Firippi E, Gy B, Boutelier T, Khormi I, Al-Iedani O, Lechner-Scott J, Ramadan S, Liebig P, Schuenke P, Zaiss M, Casagranda S. CEST 2022 - Fast WASABI post-processing: Access to rapid B 0 and B 1 correction in clinical routine for CEST MRI. Magn Reson Imaging 2023:S0730-725X(23)00097-8. [PMID: 37321377 DOI: 10.1016/j.mri.2023.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 03/20/2023] [Accepted: 06/12/2023] [Indexed: 06/17/2023]
Abstract
CEST MRI methods, such as APT and NOE imaging reveal biomarkers with significant diagnostic potential due to their ability to access molecular tissue information. Regardless of the technique used, CEST MRI data are affected by static magnetic B0 and radiofrequency B1 field inhomogeneities that degrade their contrast. For this reason, the correction of B0 field-induced artefacts is essential, whereas accounting for B1 field inhomogeneities have shown significant improvements in image readability. In a previous work, an MRI protocol called WASABI was presented, which can map simultaneously B0 and B1 field inhomogeneities, while maintaining the same sequence and readout types as used for CEST MRI. Despite the highly satisfactory quality of B0 and B1 maps computed from the WASABI data, the post-processing method is based on an exhaustive search of a four-parameter space and an additional four-parameter non-linear model fitting step. This leads to long post-processing times that are prohibitive in clinical practice. This work provides a new method for fast post-processing of WASABI data with outstanding acceleration of the parameter estimation procedure and without compromising its stability. The resulting computational acceleration makes the WASABI technique suitable for clinical use. The stability of the method is demonstrated on phantom data and clinical 3 Tesla in vivo data.
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Affiliation(s)
| | - Eleni Firippi
- Department of Research & Innovation, Olea Medical, La Ciotat, France.
| | - Benoit Gy
- Department of Research & Innovation, Olea Medical, La Ciotat, France.
| | - Timothé Boutelier
- Department of Research & Innovation, Olea Medical, La Ciotat, France.
| | - Ibrahim Khormi
- School of Health Sciences, College of Health, Medicine and Wellbeing, University of Newcastle, Newcastle, Australia; Hunter Medical Research Institute, Newcastle, Australia; College of Applied Medical Sciences, University of Jeddah, Jeddah, Saudi Arabia.
| | - Oun Al-Iedani
- Hunter Medical Research Institute, Newcastle, Australia; School of Biomedical Sciences and Pharmacy, College of Health, Medicine and Wellbeing, University of Newcastle, Newcastle, Australia.
| | - Jeannette Lechner-Scott
- Hunter Medical Research Institute, Newcastle, Australia; Department of Neurology, John Hunter Hospital, New Lambton Heights, Australia; School of Medicine and Public Health, College of Health, Medicine and Wellbeing, University of Newcastle, Newcastle, Australia.
| | - Saadallah Ramadan
- School of Health Sciences, College of Health, Medicine and Wellbeing, University of Newcastle, Newcastle, Australia; Hunter Medical Research Institute, Newcastle, Australia.
| | | | - Patrick Schuenke
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig, Berlin, Germany.
| | - Moritz Zaiss
- Institute of Neuroradiology, University Clinic Erlangen, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Erlangen, Germany.
| | - Stefano Casagranda
- Department of R&D Advanced Applications, Olea Medical, La Ciotat, France.
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10
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Adoum A, Mazzolo L, Lecler A, Sadik JC, Savatovsky J, Duron L. Co-registration with subtraction and color-coding or fusion improves the detection of new and growing lesions on follow-up MRI examination of patients with multiple sclerosis. Diagn Interv Imaging 2023:S2211-5684(23)00117-1. [PMID: 37290977 DOI: 10.1016/j.diii.2023.05.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 05/15/2023] [Accepted: 05/23/2023] [Indexed: 06/10/2023]
Abstract
PURPOSE The purpose of this study was to compare the performance of three magnetic resonance imaging (MRI) reading methods in the follow-up of patients with multiple sclerosis (MS). MATERIALS AND METHODS This retrospective study included patients with MS who underwent two brain follow-up MRI examinations with three-dimensional fluid-attenuated inversion recovery (FLAIR) sequences between September 2016 and December 2019. Two neuroradiology residents independently reviewed FLAIR images using three post-processing methods including conventional reading (CR), co-registration fusion (CF), and co-registration subtraction with color-coding (CS), while being blinded to all data but FLAIR images. The presence and number of new, growing, or shrinking lesions were compared between reading methods. The reading time, reading confidence, and inter- and intra-observer agreements were also assessed. An expert neuroradiologist established the standard of reference. Statistical analyses were corrected for multiple testing. RESULTS A total of 198 patients with MS were included. There were 130 women and 68 men, with a mean age of 41 ± 12 (standard deviation) years (age range: 21-79 years). Using CS and CF, more patients were detected with new lesions compared to CR (93/198 [47%] and 79/198 [40%] vs. 54/198 [27%], respectively; P < 0.01). The median number of new hyperintense FLAIR lesions detected was significantly greater using CS and CF compared to CR (2 [Q1, Q3: 0, 6] and 1 [Q1, Q3: 0, 3] vs. 0 [Q1, Q3: 0, 1], respectively; P < 0.001). The mean reading time was significantly shorter using CS and CF compared to CR (P < 0.001), with higher confidence in readings and higher inter- and intra-observer agreements. CONCLUSION Post-processing tools such as CS and CF substantially improve the accuracy of follow-up MRI examinations in patients with MS while reducing reading time and increasing readers' confidence and reproducibility.
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Affiliation(s)
- Akim Adoum
- Department of Neuroradiology, Hôpital Fondation Adolphe de Rothschild, 25 rue Manin, 75019 Paris, France
| | - Leila Mazzolo
- Department of Neuroradiology, Hôpital Fondation Adolphe de Rothschild, 25 rue Manin, 75019 Paris, France
| | - Augustin Lecler
- Department of Neuroradiology, Hôpital Fondation Adolphe de Rothschild, 25 rue Manin, 75019 Paris, France; Université Paris Cité, 75006 Paris, France
| | - Jean-Claude Sadik
- Department of Neuroradiology, Hôpital Fondation Adolphe de Rothschild, 25 rue Manin, 75019 Paris, France
| | - Julien Savatovsky
- Department of Neuroradiology, Hôpital Fondation Adolphe de Rothschild, 25 rue Manin, 75019 Paris, France
| | - Loïc Duron
- Department of Neuroradiology, Hôpital Fondation Adolphe de Rothschild, 25 rue Manin, 75019 Paris, France.
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11
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Volk J, Huntington J, Melton F, Minor B, Wang T, Anapalli S, Anderson R, Evett S, French A, Jasoni R, Bambach N, Kustas W, Alfieri J, Prueger J, Hipps L, McKee L, Castro S, Alsina M, McElrone A, Reba M, Runkle B, Saber M, Sanchez C, Tajfar E, Allen R, Anderson M. Post-processed data and graphical tools for a CONUS-wide eddy flux evapotranspiration dataset. Data Brief 2023; 48:109274. [PMID: 37383786 PMCID: PMC10294113 DOI: 10.1016/j.dib.2023.109274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 05/02/2023] [Accepted: 05/23/2023] [Indexed: 06/30/2023] Open
Abstract
Large sample datasets of in situ evapotranspiration (ET) measurements with well documented data provenance and quality assurance are critical for water management and many fields of earth science research. We present a post-processed ET oriented dataset at daily and monthly timesteps, from 161 stations, including 148 eddy covariance flux towers, that were chosen based on their data quality from nearly 350 stations across the contiguous United States. In addition to ET, the data includes energy and heat fluxes, meteorological measurements, and reference ET downloaded from gridMET for each flux station. Data processing techniques were conducted in a reproducible manner using open-source software. Most data initially came from the public AmeriFlux network, however, several different networks (e.g., the USDA-Agricultural Research Service) and university partners provided data that was not yet public. Initial half-hourly energy balance data were gap-filled and aggregated to daily frequency, and turbulent fluxes were corrected for energy balance closure error using the FLUXNET2015/ONEFlux energy balance ratio approach. Metadata, diagnostics of energy balance, and interactive graphs of time series data are included for each station. Although the dataset was developed primarily to benchmark satellite-based remote sensing ET models of the OpenET initiative, there are many other potential uses, such as validation for a range of regional hydrologic and atmospheric models.
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Affiliation(s)
- J.M. Volk
- Desert Research Institute, 2215 Raggio Pkwy, Reno, NV 89512 USA
| | - J.L. Huntington
- Desert Research Institute, 2215 Raggio Pkwy, Reno, NV 89512 USA
| | - F. Melton
- NASA Ames Research Center, Mail Stop 245-1, Moffett Field, CA 94035-1000 USA
- California State University, Monterey Bay, Seaside, CA 93955 USA
| | - B. Minor
- Desert Research Institute, 2215 Raggio Pkwy, Reno, NV 89512 USA
| | - T. Wang
- University of California, Berkeley, Berkeley, CA 94720 USA
| | - S. Anapalli
- USDA-ARS, Sustainable Water Management Research Unit, 4006 Old Leland Road, Stoneville, MS 38776 USA
| | - R.G. Anderson
- USDA-ARS US Salinity Laboratory, Agricultural Water Efficiency and Salinity Research Unit, 450 W Big Springs Rd Riverside, CA 92507-4617 USA
| | - S. Evett
- USDA-ARS Conservation & Production Research Laboratory, 300 Simmons Road, Bushland, TX 79012 USA
| | - A. French
- USDA-ARS US Arid-Land Agricultural Research Center, 21881 North Cardon Lane, Maricopa, AZ, 85238 USA
| | - R. Jasoni
- Desert Research Institute, 2215 Raggio Pkwy, Reno, NV 89512 USA
| | - N. Bambach
- University of California, Davis, CA 95616 USA
| | - W.P. Kustas
- USDA-ARS Hydrology and Remote Sensing Laboratory, Bldg. 007, Rm. 104, BARC-West, Beltsville, MD 20705-2350 USA
| | - J. Alfieri
- USDA-ARS Hydrology and Remote Sensing Laboratory, Bldg. 007, Rm. 104, BARC-West, Beltsville, MD 20705-2350 USA
| | - J. Prueger
- USDA-ARS National Laboratory for Agriculture and The Environment, 1015 N. University Blvd., AMES, IA 50011 USA
| | - L. Hipps
- Utah State University, Logan, UT 84322-0102 USA
| | - L. McKee
- USDA-ARS Hydrology and Remote Sensing Laboratory, Bldg. 007, Rm. 104, BARC-West, Beltsville, MD 20705-2350 USA
| | - S.J. Castro
- USDA-ARS US Salinity Laboratory, Agricultural Water Efficiency and Salinity Research Unit, 450 W Big Springs Rd Riverside, CA 92507-4617 USA
| | - M.M. Alsina
- E & J Gallo Winery, Viticulture, Chemistry and Enology, Modesto, CA USA
| | - A.J. McElrone
- Utah State University, Logan, UT 84322-0102 USA
- USDA-ARS Crops Pathology and Genetics Research Unit, Davis, CA, 95616 USA
| | - M. Reba
- USDA-ARS Delta Water Management Research, Jonesboro, AR, 72401 USA
| | - B. Runkle
- University of Arkansas, Fayetteville, AR 72701 USA
| | - M. Saber
- University of Arizona, Tucson, AZ 85721 USA
| | - C. Sanchez
- University of Arizona, Tucson, AZ 85721 USA
| | - E. Tajfar
- University of Arkansas, Fayetteville, AR 72701 USA
| | - R. Allen
- University of Idaho, Moscow, ID 83844 USA
- University of Nebraska-Lincoln, Lincoln, NE 68588 USA
| | - M. Anderson
- USDA-ARS Hydrology and Remote Sensing Laboratory, Bldg. 007, Rm. 104, BARC-West, Beltsville, MD 20705-2350 USA
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12
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Chen Z, Pawar K, Ekanayake M, Pain C, Zhong S, Egan GF. Deep Learning for Image Enhancement and Correction in Magnetic Resonance Imaging-State-of-the-Art and Challenges. J Digit Imaging 2023; 36:204-230. [PMID: 36323914 PMCID: PMC9984670 DOI: 10.1007/s10278-022-00721-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 09/09/2022] [Accepted: 10/17/2022] [Indexed: 11/06/2022] Open
Abstract
Magnetic resonance imaging (MRI) provides excellent soft-tissue contrast for clinical diagnoses and research which underpin many recent breakthroughs in medicine and biology. The post-processing of reconstructed MR images is often automated for incorporation into MRI scanners by the manufacturers and increasingly plays a critical role in the final image quality for clinical reporting and interpretation. For image enhancement and correction, the post-processing steps include noise reduction, image artefact correction, and image resolution improvements. With the recent success of deep learning in many research fields, there is great potential to apply deep learning for MR image enhancement, and recent publications have demonstrated promising results. Motivated by the rapidly growing literature in this area, in this review paper, we provide a comprehensive overview of deep learning-based methods for post-processing MR images to enhance image quality and correct image artefacts. We aim to provide researchers in MRI or other research fields, including computer vision and image processing, a literature survey of deep learning approaches for MR image enhancement. We discuss the current limitations of the application of artificial intelligence in MRI and highlight possible directions for future developments. In the era of deep learning, we highlight the importance of a critical appraisal of the explanatory information provided and the generalizability of deep learning algorithms in medical imaging.
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Affiliation(s)
- Zhaolin Chen
- Monash Biomedical Imaging, Monash University, Melbourne, VIC, 3168, Australia.
- Department of Data Science and AI, Monash University, Melbourne, VIC, Australia.
| | - Kamlesh Pawar
- Monash Biomedical Imaging, Monash University, Melbourne, VIC, 3168, Australia
| | - Mevan Ekanayake
- Monash Biomedical Imaging, Monash University, Melbourne, VIC, 3168, Australia
- Department of Electrical and Computer Systems Engineering, Monash University, Melbourne, VIC, Australia
| | - Cameron Pain
- Monash Biomedical Imaging, Monash University, Melbourne, VIC, 3168, Australia
- Department of Electrical and Computer Systems Engineering, Monash University, Melbourne, VIC, Australia
| | - Shenjun Zhong
- Monash Biomedical Imaging, Monash University, Melbourne, VIC, 3168, Australia
- National Imaging Facility, Brisbane, QLD, Australia
| | - Gary F Egan
- Monash Biomedical Imaging, Monash University, Melbourne, VIC, 3168, Australia
- Turner Institute for Brain and Mental Health, Monash University, Melbourne, VIC, Australia
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13
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da Rosa LS, Pilecco RO, Sarkis-Onofre R, Kantorski KZ, Valandro LF, Rocha Pereira GK. Should finishing, polishing or glazing be performed after grinding YSZ ceramics? A systematic review and meta-analysis. J Mech Behav Biomed Mater 2023; 138:105654. [PMID: 36634437 DOI: 10.1016/j.jmbbm.2023.105654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 12/26/2022] [Accepted: 01/01/2023] [Indexed: 01/04/2023]
Abstract
The present systematic review and meta-analysis aimed to assess the characteristics and consequences of post-processing methods after grinding procedures in YSZ ceramics on its surface roughness and flexural strength. The protocol of this review was made prospectively and is available online in the PROSPERO database (link). Literature searches on PubMed/MEDLINE, EMBASE, Lilacs, Web of Science and Scopus were conducted on December 2022 to select in vitro studies written in English, without publishing-date restrictions, that considered surface characteristics and mechanical properties of YSZ ceramics submitted to grinding and subsequent post-processing surface treatments as an attempt to revert the effect induced by grinding. Two authors independently selected the studies, extracted the data and assessed the risk of bias. Mean differences (Rev-Man 5.1, random effects model, α= 0.05) were obtained by comparing flexural strength and surface roughness values of ground surfaces with at least one post-processing surface treatment (global analysis). Subgroup analyses were performed considering the most prevalent categories of post-processing methods. A total of 33 (out of 4032) studies were eligible and included in the analysis. In the global analysis, ground surfaces showed higher flexural strength than when post-processing methodologies were employed (p< 0.0001). The subgroup analysis showed that only polishing was able to enhance the flexural strength after grinding (p= 0.001); however, when other protocols were used, the ground surface was always superior in terms of flexural strength (p< 0.0001). Post-processing techniques in both the global and sub-group analyses were able to reduce the surface roughness after grinding in YSZ ceramics (p< 0.00001). High heterogeneity was found in all the meta-analyses. Concerning the risk of bias analysis, the included studies had mixed scores for the considered factors. In conclusion, in terms of improving flexural strength and restoring surface roughness after grinding, polishing protocols can be considered the best indication as post-processing treatment after YSZ ceramics adjustments/grinding.
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Affiliation(s)
- Lucas Saldanha da Rosa
- MSciD and PhD Post-Graduate Program in Oral Sciences, Federal University of Santa Maria (UFSM), Santa Maria, RS, Brazil.
| | - Rafaela Oliveira Pilecco
- MSciD and PhD Post-Graduate Program in Oral Sciences, Federal University of Santa Maria (UFSM), Santa Maria, RS, Brazil.
| | - Rafael Sarkis-Onofre
- Graduate Program in Dentistry, Atitus Educação, Passo Fundo, Rio Grande do Sul, Brazil.
| | - Karla Zanini Kantorski
- MSciD and PhD Post-Graduate Program in Oral Sciences, Federal University of Santa Maria (UFSM), Santa Maria, RS, Brazil.
| | - Luiz Felipe Valandro
- MSciD and PhD Post-Graduate Program in Oral Sciences, Federal University of Santa Maria (UFSM), Santa Maria, RS, Brazil.
| | - Gabriel Kalil Rocha Pereira
- MSciD and PhD Post-Graduate Program in Oral Sciences, Federal University of Santa Maria (UFSM), Santa Maria, RS, Brazil.
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14
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Miloushev VZ, Boltyanskiy R, Granlund KL, Keshari KR. Improved total sensitivity estimation for multiple receive coils in MRI using ratios of first-order statistics. MAGMA 2022; 35:895-901. [PMID: 35876917 PMCID: PMC9613615 DOI: 10.1007/s10334-022-01028-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 06/10/2022] [Accepted: 06/23/2022] [Indexed: 06/15/2023]
Abstract
OBJECT Spatial variation in the sensitivity profiles of receive coils in MRI leads to spatially dependent scaling of the signal amplitude across an image. In practice, total sensitivity of the coil array is either calibrated or corrected directly by comparison to a uniform sensitivity image, fitting of coil profiles, or indirectly by constraining the reconstructed image or coil profiles. In the absence of these corrections, popular coil summation strategies are often designed to maximize the signal-to-noise ratio or optimize under-sampled encoding but not necessarily estimate the value of the signal unscaled by the coil spatial sensitivity. MATERIALS AND METHODS We use ratios of first-order statistics to approach the unscaled value of the signal at any position. Motivated by the assumption that the coil array is a sample from much larger number of possible coils, we present two approaches to scale the mean signal in all coils: (1) an argument for use of the mode of the normalized signals, and (2) using a one-dimensional analog derive an approximate expression for scaling with the ratio of the square-of-the-mean to the mean-of-the-squares. We test these approaches with simulation where idealized coil elements are arrayed around an object, and on directly acquired data with an 8-channel coil array on a uniform 13C phantom, and on Hyperpolarized 13C pyruvate brain MRI. RESULTS We show improved image uniformity using the ratios of first order statistics compared to a simple homomorphic filter, noting that these approaches are more sensitive to noise. DISCUSSION We present simple methods for correcting the spatial variation in sensitivity profiles in the context of a coil array. These methods can be used as an initial or adjunct step in data post-processing.
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Affiliation(s)
- Vesselin Z Miloushev
- Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY, 10065, USA.
| | | | | | - Kayvan R Keshari
- Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY, 10065, USA
- Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
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15
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Liao W, Sifton MA, Thomas SC. Biochar granulation reduces substrate erosion on green roofs. Biochar 2022; 4:61. [PMID: 36317055 PMCID: PMC9613583 DOI: 10.1007/s42773-022-00186-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 10/12/2022] [Indexed: 06/16/2023]
Abstract
UNLABELLED Green roofs are exposed to high winds and harsh environmental conditions that can degrade vegetation and erode substrate material, with negative consequences to ecosystem services. Biochar has been promoted as an effective substrate additive to enhance plant performance, but unprocessed biochars are susceptible to wind and water erosion. Applications of granulated biochars or chemical dust suppressants are suggested as a means to mitigate biochar and substrate erosion; however, research on biochar type and chemical dust suppressant use on biochar and substrate erosion is lacking. Vegetation is a crucial factor that influences substrate erosion, yet plant responses may vary with biochar type and chemical dust suppressant; thus, the effects of possible mitigation measures on biochar and substrate erosion are unclear. We investigated the effects of surface-applied granulated and unprocessed biochars and an organic dust suppressant (Entac™) on biochar and substrate erosion on green roofs with Sedum album L. and a native plant mix. Our results show that 94% of unprocessed biochars were lost from green roofs after 2 years regardless of the Entac™ amendment, likely due to the lightweight nature and fragmentation of biochar particles. In contrast, granulation of biochars reduced the biochar erosion and total substrate erosion by 74% and 39%, respectively, possibly due to enhanced biochar bulk density and particle size and improved moisture retention of biochar-amended substrates. Additionally, Sedum album better reduced biochar and substrate erosion than the native plant mix, likely due to rapid development of high vegetation cover that reduced wind exposure and enhanced substrate moisture retention. We conclude that applications of granulated biochars can substantially reduce biochar and substrate erosion on green roofs, improving green roof sustainability. SUPPLEMENTARY INFORMATION The online version contains supplementary material available at 10.1007/s42773-022-00186-7.
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Affiliation(s)
- Wenxi Liao
- Institute of Forestry and Conservation, John H Daniels Faculty of Architecture Landscape and Design, University of Toronto, 33 Willcocks St., Toronto, ON M5S 3B3 Canada
| | - Melanie A. Sifton
- Institute of Forestry and Conservation, John H Daniels Faculty of Architecture Landscape and Design, University of Toronto, 33 Willcocks St., Toronto, ON M5S 3B3 Canada
| | - Sean C. Thomas
- Institute of Forestry and Conservation, John H Daniels Faculty of Architecture Landscape and Design, University of Toronto, 33 Willcocks St., Toronto, ON M5S 3B3 Canada
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16
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Liao W, Drake J, Thomas SC. Biochar granulation, particle size, and vegetation effects on leachate water quality from a green roof substrate. J Environ Manage 2022; 318:115506. [PMID: 35753127 DOI: 10.1016/j.jenvman.2022.115506] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 06/06/2022] [Accepted: 06/08/2022] [Indexed: 06/15/2023]
Abstract
Biochar, due to its favourable physiochemical properties, has been promoted as an ideal substrate additive on green roofs, with potential benefits to hydrological function. However, biochar is susceptible to water erosion, which may result in biochar loss and water pollution. The use of granulated biochars or biochars in large particle sizes could potentially alleviate biochar erosion loss, but effects on leachate quality have not been investigated. Also, biochar type and particle size influence plant performance, and effects on discharge quality may vary with vegetation. We assessed the effects of unprocessed and granulated biochars at five (0.25-0.5 mm, 0.5-1 mm, 1-2 mm, 2-2.8 mm, 2.8-4 mm) and four (1-2 mm, 2-2.8 mm, 2.8-4 mm, and 4-6.3 mm) particle size ranges, respectively, on leachate quality on a typical green roof substrate, with presence and absence of vegetation (Agastache foeniculum - a drought-tolerant native forb). We evaluated integrated leachate quality using the CCME Water Quality Index (WQI). Unprocessed biochars reduced nutrient leaching due to increased water retention capacity (WRC) and total porosity. In contrast, granulated biochars, although showing less pronounced mitigation of nutrient leaching, reduced total suspended solids (TSS) and improved WQI in leachate due to enhanced plant performance. In addition, small biochar particles better reduced nutrient leaching and particle loss than large biochar particles, possibly due to increased WRC and formation of water-stable aggregates. The presence of vegetation generally reduced the leaching of nutrients and TSS, consistent with plant nutrient uptake and root substrate stabilization. However, plant biomass was correlated with increased total N leaching, likely due to litter inputs and rapid litter decomposition. We conclude that applications of granulated biochars may best improve discharge quality from green roofs through sorption effects and by enhancing plant performance.
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Affiliation(s)
- Wenxi Liao
- Institute of Forestry and Conservation, John H Daniels Faculty of Architecture Landscape and Design, University of Toronto, 33 Willcocks St., Toronto, ON, M5S 3B3, Canada.
| | - Jennifer Drake
- Department of Civil and Mineral Engineering, University of Toronto, 35 St. George St., Toronto, ON, M5S 1A4, Canada
| | - Sean C Thomas
- Institute of Forestry and Conservation, John H Daniels Faculty of Architecture Landscape and Design, University of Toronto, 33 Willcocks St., Toronto, ON, M5S 3B3, Canada
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17
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Shin JY, Min B, Kim KR. High-resolution wind speed forecast system coupling numerical weather prediction and machine learning for agricultural studies - a case study from South Korea. Int J Biometeorol 2022; 66:1429-1443. [PMID: 35449427 PMCID: PMC9151559 DOI: 10.1007/s00484-022-02287-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Revised: 03/22/2022] [Accepted: 04/06/2022] [Indexed: 05/08/2023]
Abstract
Forecasting wind speed near the surface with high-spatial resolution is beneficial in agricultural management. There is a discrepancy between the wind speed information required for agricultural management and that produced by weather agencies. To improve crop yield and increase farmers' incomes, wind speed prediction systems must be developed that are customized for agricultural needs. The current study developed a high-resolution wind speed forecast system for agricultural purposes in South Korea. The system produces a wind speed forecast at 3 m aboveground with 100-m spatial resolution across South Korea. Logarithmic wind profile, power law, random forests, support vector regression, and extreme learning machine were tested as candidate methods for the downscaling wind speed data. The wind speed forecast system developed in this study provides good performance, particularly in inland areas. The machine learning-based methods give the better performance than traditional methods for downscaling wind speed data. Overall, the random forests are considered the best downscaling method in this study. Root mean square error and mean absolute error of wind speed prediction for 48 h using random forests are approximately 0.8 m/s and 0.5 m/s, respectively.
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Affiliation(s)
- Ju-Young Shin
- High Impact Weather Research Department, National Institute of Meteorological Sciences, 33 Seohobuk-ro, Seogwipo-si, Jeju-do, 63568, South Korea.
| | - Byunghoon Min
- High Impact Weather Research Department, National Institute of Meteorological Sciences, 33 Seohobuk-ro, Seogwipo-si, Jeju-do, 63568, South Korea
| | - Kyu Rang Kim
- High Impact Weather Research Department, National Institute of Meteorological Sciences, 33 Seohobuk-ro, Seogwipo-si, Jeju-do, 63568, South Korea
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Lambart AL, Xepapadeas AB, Koos B, Li P, Spintzyk S. Rinsing postprocessing procedure of a 3D-printed orthodontic appliance material: Impact of alternative post-rinsing solutions on the roughness, flexural strength and cytotoxicity. Dent Mater 2022; 38:1344-1353. [PMID: 35752470 DOI: 10.1016/j.dental.2022.06.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 05/04/2022] [Accepted: 06/05/2022] [Indexed: 11/03/2022]
Abstract
OBJECTIVE The present study evaluated the effect of different rinsing postprocessing solutions on surface characteristics, flexural strength, and cytotoxicity of an additive manufactured polymer for orthodontic appliances. These solutions have been deemed an alternative to the standard isopropanol which is a flammable liquid, known to have toxic effects. METHODS Tested specimens were manufactured using direct light processing of an orthodontic appliance polymer (FREEPRINT® splint 2.0, Detax) and post-processed with different post-rinsing solutions, including isopropanol (IPA), ethanol (EtOH), EASY 3D Cleaner (EYC), Yellow Magic7 (YM7), and RESINAWAY (RAY), respectively. All groups were post-cured following the manufacturer's instructions. Surface topography and roughness (Ra and Rv) were evaluated. In addition, flexural strength was measured by a three-point bending test. An extract test was performed to evaluate cytotoxicity. The data were analyzed by the Kruskal-Wallis test with Dunn's multiple comparisons test (p < 0.05). RESULTS Various post-rinsing solutions did not significantly affect the roughness values (Ra and Rv). Specimens post-processed with EtOH (98.1 ± 12.4 MPa) and EYC (101.1 ± 6.3 MPa) exhibited significantly lower flexural strength compared to the groups of IPA (110.7 ± 5.3 MPa), RAY (112.1 ± 5.6 MPa) and YM7 (117.3 ± 5.9 MPa), respectively. Finally, there were no cytotoxic effects of parts cleaned with different post-rinsing solutions. SIGNIFICANCE Considering the use of 3D-printed orthodontic appliance materials, different rinsing postprocessing procedures did not affect surface characteristics. However, the flexural strength was significantly influenced, which could be attributed to the chemical ingredients of the post-rinsing solutions. Various post-rinsing treatments had no alternation concerning cytocompatibility.
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Affiliation(s)
- Anna-Lena Lambart
- Department of Orthodontics, University Hospital Tübingen, Osianderstrasse 2-8, Tübingen 72076, Germany; Medical Materials Science and Technology, University Hospital Tübingen, Osianderstrasse 2-8, Tübingen 72076, Germany
| | - Alexander B Xepapadeas
- Department of Orthodontics, University Hospital Tübingen, Osianderstrasse 2-8, Tübingen 72076, Germany
| | - Bernd Koos
- Department of Orthodontics, University Hospital Tübingen, Osianderstrasse 2-8, Tübingen 72076, Germany
| | - Ping Li
- Center of Oral Implantology, Stomatological Hospital, Southern Medical University, South Jiangnan Road No. 366, Guangzhou 510280, China; Medical Materials Science and Technology, University Hospital Tübingen, Osianderstrasse 2-8, Tübingen 72076, Germany.
| | - Sebastian Spintzyk
- Medical Materials Science and Technology, University Hospital Tübingen, Osianderstrasse 2-8, Tübingen 72076, Germany; ADMiRE Lab - Additive Manufacturing, intelligent Robotics, Sensors and Engineering, School of Engineering and IT, Carinthia University of Applied Sciences, Europastraße 4, 9524 Villach, Austria
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Edla DR, Simi VR, Joseph J. A Noise-robust and Overshoot-free Alternative to Unsharp Masking for Enhancing the Acuity of MR Images. J Digit Imaging 2022; 35:1041-1060. [PMID: 35296942 PMCID: PMC9485367 DOI: 10.1007/s10278-022-00585-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 09/18/2021] [Accepted: 01/11/2022] [Indexed: 11/30/2022] Open
Abstract
Poor acutance of images (unsharpness) is one of the major concerns in magnetic resonance imaging (MRI). MRI-based diagnosis and clinical interventions become difficult due to the vague textural information and weak morphological margins on images. A novel image sharpening algorithm named as maximum local variation-based unsharp masking (MLVUM) to address the issue of 'unsharpness' in MRI is proposed in this paper. In the MLVUM, the sharpened image is the algebraic sum of the input image and the product of the user-defined scale and the difference between the output of a newly designed nonlinear spatial filter named maximum local variation-controlled edge smoothing Gaussian filter (MLVESGF) and the input image, weighted by the normalised MLV. The MLVESGF is a locally adaptive 2D Gaussian edge smoothing kernel whose standard deviation is directly proportional to the local value of the normalized MLV. The values of the acutance-to-noise ratio (ANR) and absolute mean brightness error (AMBE) shown by the MLVUM on 100 MRI slices are 0.6463 ± 0.1852 and 0.3323 ± 0.2200, respectively. Compared to 17 state-of-the-art image sharpening algorithms, the MLVUM exhibited a higher ANR and lower AMBE. The MLVUM selectively enhances the sharpness of edges in the MR images without amplifying the background noise without altering the mean brightness level.
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Affiliation(s)
- Damodar Reddy Edla
- Department of Computer Science and Engineering, National Institute of Technology, Goa, 403401, India
| | - V R Simi
- Department of Computer Science and Engineering, National Institute of Technology, Goa, 403401, India.
| | - Justin Joseph
- School of Bioengineering, VIT University, Bhopal, Madhya Pradesh, 466114, India
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Oztek MA, Parisi MT, Perez FA, Kim HHR, Otjen JP, Phillips GS. Improving the detection of ventricular shunt disruption using volume-rendered three-dimensional head computed tomography. Pediatr Radiol 2022; 52:549-58. [PMID: 34535807 DOI: 10.1007/s00247-021-05190-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 07/15/2021] [Accepted: 08/12/2021] [Indexed: 10/20/2022]
Abstract
Hydrocephalus is the most common neurosurgical disorder in children, and cerebrospinal fluid (CSF) diversion with shunt placement is the most commonly performed pediatric neurosurgical procedure. CT is frequently used to evaluate children with suspected CSF shunt malfunction to assess change in ventricular size. Moreover, careful review of the CT images is important to confirm the integrity of the imaged portions of the shunt system. Subtle shunt disruptions can be missed on multiplanar two-dimensional (2-D) CT images, especially when the disruption lies in the plane of imaging. The use of volume-rendered CT images enables radiologists to view the extracranial shunt tubing within the field of view as a three-dimensional (3-D) object. This allows for a rapid and intuitive method of assessing the integrity of the extracranial shunt tubing. The purpose of this pictorial essay is to discuss how volume-rendered CT images can be generated to evaluate CSF shunts in the pediatric population and to provide several examples of their utility in diagnosing shunt disruption. We also address the potential pitfalls of this technique and ways to avoid them.
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21
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Zrzavy T, Wielandner A, Haider L, Bartsch S, Leutmezer F, Berger T, Nenning KH, Rauscher A, Rommer P, Kasprian G. FLAIR 2 post-processing: improving MS lesion detection in standard MS imaging protocols. J Neurol 2022; 269:461-467. [PMID: 34623512 PMCID: PMC8738502 DOI: 10.1007/s00415-021-10833-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 09/29/2021] [Accepted: 09/29/2021] [Indexed: 11/25/2022]
Abstract
BACKGROUND Technical improvements in magnetic resonance imaging (MRI) acquisition, such as higher field strength and optimized sequences, lead to better multiple sclerosis (MS) lesion detection and characterization. Multiplication of 3D-FLAIR with 3D-T2 sequences (FLAIR2) results in isovoxel images with increased contrast-to-noise ratio, increased white-gray-matter contrast, and improved MS lesion visualization without increasing MRI acquisition time. The current study aims to assess the potential of 3D-FLAIR2 in detecting cortical/leucocortical (LC), juxtacortical (JC), and white matter (WM) lesions. OBJECTIVE To compare lesion detection of 3D-FLAIR2 with state-of-the-art 3D-T2-FLAIR and 3D-T2-weighted images. METHODS We retrospectively analyzed MRI scans of thirteen MS patients, showing previously noted high cortical lesion load. Scans were acquired using a 3 T MRI scanner. WM, JC, and LC lesions were manually labeled and manually counted after randomization of 3D-T2, 3D-FLAIR, and 3D-FLAIR2 scans using the ITK-SNAP tool. RESULTS LC lesion visibility was significantly improved by 3D-FLAIR2 in comparison to 3D-FLAIR (4 vs 1; p = 0.018) and 3D-T2 (4 vs 1; p = 0.007). Comparing LC lesion detection in 3D-FLAIR2 vs. 3D-FLAIR, 3D-FLAIR2 detected on average 3.2 more cortical lesions (95% CI - 9.1 to 2.8). Comparing against 3D-T2, 3D-FLAIR2 detected on average 3.7 more LC lesions (95% CI 3.3-10.7). CONCLUSIONS 3D-FLAIR2 is an easily applicable time-sparing MR post-processing method to improve cortical lesion detection. Larger sampled studies are warranted to validate the sensitivity and specificity of 3D-FLAIR2.
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Affiliation(s)
- Tobias Zrzavy
- Department of Neurology, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria
| | - Alice Wielandner
- Department of Biomedical Imaging and Image Guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Lukas Haider
- Department of Biomedical Imaging and Image Guided Therapy, Medical University of Vienna, Vienna, Austria
- NMR Research UnitDepartment of NeuroinflammationFaculty of Brain Science, Queens Square MS CentreUCL Queen Square Institute of NeurologyUniversity College London, London, UK
| | - Sophie Bartsch
- Department of Biomedical Imaging and Image Guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Fritz Leutmezer
- Department of Neurology, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria
| | - Thomas Berger
- Department of Neurology, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria
| | - Karl Heinz Nenning
- Department of Biomedical Imaging and Image Guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Alexander Rauscher
- UBC MRI Research Centre, University of British Columbia, Vancouver, BC, Canada
| | - Paulus Rommer
- Department of Neurology, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria.
| | - Gregor Kasprian
- Department of Biomedical Imaging and Image Guided Therapy, Medical University of Vienna, Vienna, Austria
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Gari Pcan AM, Erdem E. Design, FPGA implementation and statistical analysis of a high-speed and low-area TRNG based on an AES s-box post-processing technique. ISA Trans 2021; 117:160-171. [PMID: 33551130 DOI: 10.1016/j.isatra.2021.01.054] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 01/06/2021] [Accepted: 01/25/2021] [Indexed: 06/12/2023]
Abstract
The statistical weakness problem occurring as a result of physical randomness is an important shortcoming of TRNGs. Post-processing techniques are generally used in the literature to overcome this shortcoming. In this study, the hardware implementation of Advanced Encryption Standard (AES) substitution box (s-box)-based novel post-processing technique is presented. The low-cost novel method is based on the substitution s-box transformations and can successfully remove the statistical weakness problem of TRNGs. The real-time verification of the proposed post-processing is done by applying ring oscillator (RO) based TRNG architecture in four different scenarios on Field Programmable Gate Array (FPGA) environment. Successful statistical results obtained from bias, correlation, entropy and NIST 800-22 tests confirm the usability of the proposed method for cryptographic purposes. The low area-energy requirement, practicality and compressionless properties of the post-processing provide better tradeoff for TRNG compared to known methods in the literature. For this reason, TRNG's performance is high. Furthermore, the presented study is important in demonstrating that s-boxes with good mathematical encryption properties can also be used for different cryptographic purposes.
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Affiliation(s)
| | - Ebubekir Erdem
- Department of Computer Engineering, Fırat University, Elazığ, Turkey.
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Yazdandoost F, Zakipour M, Izadi A. Copula based post-processing for improving the NMME precipitation forecasts. Heliyon 2021; 7:e07877. [PMID: 34504971 PMCID: PMC8417337 DOI: 10.1016/j.heliyon.2021.e07877] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Revised: 02/08/2021] [Accepted: 08/23/2021] [Indexed: 11/30/2022] Open
Abstract
Using reliable and timely precipitation forecasts on a monthly or seasonal scale could be useful in many water resources management planning, especially in countries facing drought challenges. Amongst many, the North American Multi-Model Ensemble (NMME) is one of the most well-known models. In this study, a Bayesian method based on Copula functions has been applied to improve NMME precipitation forecasts. This method is based on the existence of a correlation between the raw forecast and observational data. Two main factors affect the results of rainfall improvement based on the selected method. This research has presented innovative methods in these regards namely; 1) the approach of selecting the appropriate statistical distribution for variables and 2) the selection method of improved data according to the conditional probability distribution functions (CPDF). To evaluate the effectiveness of the statistical distribution, firstly the precipitation forecast improvement model has been developed based on the application of parametric (Exponential, Normal, Gamma, LogNormal and General Exreteme Value (GEV)) and non-parametric distributions (Standard Normal Kernel). Then the novel mixed distribution function based on GEV parametric distribution and Standard Normal Kernel (non-parametric distribution) has been suggested. As the second aim, a new method for selecting improved data based on the center of mass of estimated CPDF is presented. The evaluation of the proposed method for estimating the statistical distribution of data and improving the forecast precipitation by the NMME model has been performed in Sistan and Baluchestan province in Iran. In this regard, the data of 1982–2010 for the calibration period and the data of 2012–2016 for the validation of the results have been used. According to the results, the non-parametric distribution best fitted with the data in the time series and selecting the appropriate bandwidth increased the efficiency of this distribution. Besides, due to the weakness of non-parametric distributions in the boundaries, the use of GEV distribution with a high ability to estimate boundary conditions as semi-parametric distribution, led to improved performance of the proposed distribution. Finally, the selection of the improved data based on the center of the mass method has efficiently provided much improvement compared to the maximum likelihood method commonly used.
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Affiliation(s)
- Farhad Yazdandoost
- Department of Civil Engineering, K. N. Toosi University of Technology, Tehran, Iran
| | - Mina Zakipour
- Department of Civil Engineering, K. N. Toosi University of Technology, Tehran, Iran
| | - Ardalan Izadi
- Multidisciplinary International Complex (MIC), K. N. Toosi University of Technology, Tehran, Iran
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Arnold M, Speidel S, Hattab G. Towards improving edge quality using combinatorial optimization and a novel skeletonize algorithm. BMC Med Imaging 2021; 21:119. [PMID: 34353290 PMCID: PMC8340540 DOI: 10.1186/s12880-021-00650-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 07/14/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Object detection and image segmentation of regions of interest provide the foundation for numerous pipelines across disciplines. Robust and accurate computer vision methods are needed to properly solve image-based tasks. Multiple algorithms have been developed to solely detect edges in images. Constrained to the problem of creating a thin, one-pixel wide, edge from a predicted object boundary, we require an algorithm that removes pixels while preserving the topology. Thanks to skeletonize algorithms, an object boundary is transformed into an edge; contrasting uncertainty with exact positions. METHODS To extract edges from boundaries generated from different algorithms, we present a computational pipeline that relies on: a novel skeletonize algorithm, a non-exhaustive discrete parameter search to find the optimal parameter combination of a specific post-processing pipeline, and an extensive evaluation using three data sets from the medical and natural image domains (kidney boundaries, NYU-Depth V2, BSDS 500). While the skeletonize algorithm was compared to classical topological skeletons, the validity of our post-processing algorithm was evaluated by integrating the original post-processing methods from six different works. RESULTS Using the state of the art metrics, precision and recall based Signed Distance Error (SDE) and the Intersection over Union bounding box (IOU-box), our results indicate that the SDE metric for these edges is improved up to 2.3 times. CONCLUSIONS Our work provides guidance for parameter tuning and algorithm selection in the post-processing of predicted object boundaries.
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Affiliation(s)
- Marvin Arnold
- Division of Translational Surgical Oncology (TSO), National Center for Tumor Diseases (NCT/UCC) Dresden, Fetcherstr. 74, 01039, Dresden, Germany.
| | - Stefanie Speidel
- Division of Translational Surgical Oncology (TSO), National Center for Tumor Diseases (NCT/UCC) Dresden, Fetcherstr. 74, 01039, Dresden, Germany
| | - Georges Hattab
- Department of Mathematics and Computer Science, University of Marburg, Hans-Meerwein-Str. 6, 35032, Marburg, Germany
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Nakao LTH, Krueger CP, Bleninger T. Benchmarking for using an acoustic Doppler current profiler for bathymetric survey. Environ Monit Assess 2021; 193:356. [PMID: 34031780 DOI: 10.1007/s10661-021-09073-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 04/11/2021] [Indexed: 06/12/2023]
Abstract
This research aims to improve data post-processing from an acoustic Doppler current profiler (ADCP) to obtain additional depth information with a high-quality bathymetric result. To validate the depth, dataset in a control area was used a scaled rod, the RTK (Real-Time Kinematic) positioning technique, and a single beam echo sounder (SBES). The developed post-processing and validation in the control area applied to a small region of a water supply reservoir in Brazil. A robust local regression method eliminated outliers from the raw data. Subsequently, a linear regression model was generated for the beams from the ADCP to adjust depths and improve the dataset. The statistical hypothesis test performed before and after the adjustment supported the validation of data processing. The resulting volumes calculated from the ADCP raw data showed a difference of 30% with SBES, which is usually the standard equipment used for bathymetric surveys. The proposed post-processing techniques declined to < 1% of the volume discrepancy. The raw dataset standard deviation was 0.15 m on average for Doppler beams, and after adjusts, this value dropped to 0.03 m. The results showed the necessity of a post-processing method to improve depth data quality from ADCP. Thus, the procedure described in this document can be used for bathymetric surveys using ADCP for analysis concerning the estimation of reservoir volume.
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Affiliation(s)
- Laís T Hasuda Nakao
- Department of Hydraulics and Sanitation, Federal University of Parana, Curitiba, Brazil.
| | - Claudia Pereira Krueger
- Coordinator of the Laboratory of Space Geodesy and Hydrography, Department of Geomatics, Federal University of Parana, Curitiba, Brazil
| | - Tobias Bleninger
- Department of Environmental Engineering, Federal University of Parana, Curitiba, Brazil
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Zhang Y, Mui D, Chirinos JA, Zamani P, Ferrari VA, Chen Y, Han Y. Comparing cardiovascular magnetic resonance strain software packages by their abilities to discriminate outcomes in patients with heart failure with preserved ejection fraction. J Cardiovasc Magn Reson 2021; 23:55. [PMID: 34011382 PMCID: PMC8136221 DOI: 10.1186/s12968-021-00747-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 03/18/2021] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Cardiovascular magnetic resonance (CMR) myocardial strain analysis using feature tracking (FT) is an increasingly popular method to assess cardiac function. However, different software packages produce different strain values from the same images and there is little guidance regarding which software package would be the best to use. We explored a framework under which different software packages could be compared and used based on their abilities to differentiate disease from health and differentiate disease severity based on outcome. METHOD To illustrate this concept, we compared 4-chamber left ventricular (LV) peak longitudinal strain (GLS) analyzed from retrospective electrocardiogram gated cine imaging performed on 1.5 T CMR scanners using three CMR post-processing software packages in their abilities to discriminate a group of 45 patients with heart failure with preserved ejection fraction (HFpEF) from 26 controls without cardiovascular disease and to discriminate disease severity based on outcomes. The three different post-processing software used were SuiteHeart, cvi42, and DRA-Trufistrain. RESULTS All three software packages were able to distinguish HFpEF patients from controls. 4-chamber peak GLS by SuiteHeart was shown to be a better discriminator of adverse outcomes in HFpEF patients than 4-chamber GLS derived from cvi42 or DRA-Trufistrain. CONCLUSION We illustrated a framework to compare feature tracking GLS derived from different post-processing software packages. Publicly available imaging data sets with outcomes would be important to validate the growing number of CMR-FT software packages.
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Affiliation(s)
- Ying Zhang
- Cardiovascular Division, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, 3400 Civic Center Blvd, Philadelphia, PA 19104 USA
- PLA General Hospital, Beijing, China
| | - David Mui
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA USA
| | - Julio A. Chirinos
- Cardiovascular Division, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, 3400 Civic Center Blvd, Philadelphia, PA 19104 USA
| | - Payman Zamani
- Cardiovascular Division, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, 3400 Civic Center Blvd, Philadelphia, PA 19104 USA
| | - Victor A. Ferrari
- Cardiovascular Division, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, 3400 Civic Center Blvd, Philadelphia, PA 19104 USA
| | - Yucheng Chen
- Department of Cardiology, West China Hospital, Chengdu, China
| | - Yuchi Han
- Cardiovascular Division, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, 3400 Civic Center Blvd, Philadelphia, PA 19104 USA
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Mayer J, Stawarczyk B, Vogt K, Hickel R, Edelhoff D, Reymus M. Influence of cleaning methods after 3D printing on two-body wear and fracture load of resin-based temporary crown and bridge material. Clin Oral Investig 2021; 25:5987-5996. [PMID: 33811531 DOI: 10.1007/s00784-021-03905-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 03/19/2021] [Indexed: 12/29/2022]
Abstract
OBJECTIVES To investigate the impact of different cleaning methods on the fracture load and two-body wear of additively manufactured three-unit fixed dental prostheses (FDP) for long-term temporary use, compared to the respective outcomes of milled provisional PMMA FDPs. MATERIALS AND METHODS Shape congruent three-unit FDPs were 3D printed using three different resin-based materials [FPT, GCT, NMF] or milled [TEL] (N = 48, n = 16 per group). After printing, the FDPs were cleaned using: Isopropanol (ISO), Yellow Magic 7 (YEL), or centrifugal force (CEN). Chewing simulation was carried out with a vertical load of 50 N (480,000 × 5 °C/55 °C). Two-body wear and fracture load were measured. Data were analyzed using global univariate ANOVA with partial eta squared, Kruskal-Wallis H, Mann-Whitney U, and Spearman's rho test (p < 0.05). RESULTS TEL showed less wear resistance than FPT (p = 0.001) for all cleaning methods tested. Concerning vertical material loss, NMF and GCT were in the same range of value (p = 0.419-0.997), except within FDPs cleaned in ISO (p = 0.021). FPT showed no impact of cleaning method on wear resistance (p = 0.219-0.692). TEL (p < 0.001) showed the highest and FPT (p < 0.001) the lowest fracture load. Regarding the cleaning methods, specimens treated with ISO showed lower fracture load than specimens cleaned with CEN (p = 0.044) or YEL (p = 0.036). CONCLUSIONS The material selection and the cleaning method can have an impact on two-body wear and fracture load results. CLINICAL RELEVANCE Printed restorations showed superior two-body wear resistance compared to milled FDPs but lower fracture load values. Regarding cleaning methods, ISO showed a negative effect on fracture load compared to the other methods tested.
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Affiliation(s)
- Johannes Mayer
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestrasse 70, 80336, Munich, Germany.
| | - Bogna Stawarczyk
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestrasse 70, 80336, Munich, Germany
| | - Konstantin Vogt
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestrasse 70, 80336, Munich, Germany
| | - Reinhard Hickel
- Department of Conservative Dentistry and Periodontology, University Hospital, LMU Munich, Goethestrasse 70, 80336, Munich, Germany
| | - Daniel Edelhoff
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestrasse 70, 80336, Munich, Germany
| | - Marcel Reymus
- Department of Conservative Dentistry and Periodontology, University Hospital, LMU Munich, Goethestrasse 70, 80336, Munich, Germany
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Chow LS, Paley MNJ. Recent advances on optic nerve magnetic resonance imaging and post-processing. Magn Reson Imaging 2021; 79:76-84. [PMID: 33753137 DOI: 10.1016/j.mri.2021.03.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 03/17/2021] [Accepted: 03/17/2021] [Indexed: 11/27/2022]
Abstract
The optic nerve is known to be one of the largest nerve bundles in the human central nervous system. There have been many studies of optic nerve imaging and post-processing that have provided insights into pathophysiology of optic neuritis related to multiple sclerosis and neuromyelitis optica spectrum disorder, glaucoma, and Leber's hereditary optic neuropathy. There are many challenges in optic nerve imaging, due to the morphology of the nerve through its course to the optic chiasm, its mobility due to eye movements and the high signal from cerebrospinal fluid and orbital fat surrounding the optic nerve. Recently, many advanced and fast imaging sequences have been used with post-processing techniques in attempts to produce higher resolution images of the optic nerve for evaluating various diseases. Magnetic resonance imaging (MRI) is one of the most common imaging methodologies for the optic nerve. This review paper will focus on recent MRI advances in optic nerve imaging and explain several post-processing techniques being used for analysis of optic nerve images. Finally, some challenges and potential for future optic nerve studies will be discussed.
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Affiliation(s)
- Li Sze Chow
- Department of Electrical and Electronic Engineering, Faculty of Engineering and Built Environment, UCSI University, 1, Jalan Puncak Menara Gading, Taman Connaught, 56000 Cheras, Kuala Lumpur, Malaysia.
| | - Martyn N J Paley
- Department of Infection, Immunity and Cardiovascular Disease, The Medical School, The University of Sheffield, Beech Hill Road, Sheffield S10 2RX, UK.
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Zimmerman SL, Rowe SP, Fishman EK. Cinematic rendering of CT angiography for visualization of complex vascular anatomy after hybrid endovascular aortic aneurysm repair. Emerg Radiol 2021; 28:839-843. [PMID: 33651233 DOI: 10.1007/s10140-021-01922-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Accepted: 02/23/2021] [Indexed: 10/22/2022]
Abstract
The purpose of this study is to demonstrate the utility of cinematic rendering (CR) techniques for imaging of patients who have undergone hybrid repair of thoracoabdominal aortic aneurysms that are difficult to assess given anatomic complexity, particularly in the emergency setting. In this pictorial essay, we will explain why CR techniques are uniquely suited to improving anatomic visualization in patients with complex postoperative vascular anatomy. Verification of vessel patency is critical to optimal care of these patients in any setting, particularly in the emergency patient when clinical history may be lacking. Cinematic rendering (CR) is a recently developed CT post-processing technique for creating photorealistic anatomic visualization. Hybrid abdominal aortic aneurysm repairs involve the use of multiple tortuous and overlapping grafts to preserve blood flow to visceral arteries, which are difficult to adequately evaluate using standard orthogonal planes and with traditional VR techniques. Several examples of complex aortic repairs show the utility of CR for improved visualization of these structures. CR improves upon standard 3D volumetric techniques through improved depiction of the spatial relationships of anatomic structures in 3D space, permitting near life-like visualization that allows the imager to simplify the visualization of highly complex anatomy.
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Affiliation(s)
- Stefan L Zimmerman
- Johns Hopkins University School of Medicine, Baltimore, MD, USA. .,, Baltimore, USA.
| | - Steven P Rowe
- Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Thomas SC. Post-processing of biochars to enhance plant growth responses: a review and meta-analysis. Biochar 2021; 3:437-455. [PMID: 34723131 PMCID: PMC8547209 DOI: 10.1007/s42773-021-00115-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 07/14/2021] [Indexed: 05/15/2023]
Abstract
UNLABELLED A number of processes for post-production treatment of "raw" biochars, including leaching, aeration, grinding or sieving to reduce particle size, and chemical or steam activation, have been suggested as means to enhance biochar effectiveness in agriculture, forestry, and environmental restoration. Here, I review studies on post-production processing methods and their effects on biochar physio-chemical properties and present a meta-analysis of plant growth and yield responses to post-processed vs. "raw" biochars. Data from 23 studies provide a total of 112 comparisons of responses to processed vs. unprocessed biochars, and 103 comparisons allowing assessment of effects relative to biochar particle size; additional 8 published studies involving 32 comparisons provide data on effects of biochar leachates. Overall, post-processed biochars resulted in significantly increased average plant growth responses 14% above those observed with unprocessed biochar. This overall effect was driven by plant growth responses to reduced biochar particle size, and heating/aeration treatments. The assessment of biochar effects by particle size indicates a peak at a particle size of 0.5-1.0 mm. Biochar leachate treatments showed very high heterogeneity among studies and no average growth benefit. I conclude that physiochemical post-processing of biochar offers substantial additional agronomic benefits compared to the use of unprocessed biochar. Further research on post-production treatments effects will be important for biochar utilization to maximize benefits to carbon sequestration and system productivity in agriculture, forestry, and environmental restoration. SUPPLEMENTARY INFORMATION The online version contains supplementary material available at 10.1007/s42773-021-00115-0.
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Affiliation(s)
- Sean C. Thomas
- Institute of Forestry and Conservation, University of Toronto, 33 Willcocks St., Toronto, ON M5S 3B3 Canada
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Abstract
There are many technical and nontechnical steps involved in a successful clinical functional MRI (fMRI) scan. The output from scanning and analysis can only be as good as the input, so task instruction and rehearsal are the most important steps during an clinical fMRI procedure. Properly pre-processed data significantly affects statistical analysis, which has a great impact on image interpretation. Even though there is general agreement on how to process clinical fMRI data, such as algorithms for head motion detection and correction, the theory and practicalities associated with data processing remain complex and constantly evolving.
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Baldazzi G, Sulas E, Urru M, Tumbarello R, Raffo L, Pani D. Wavelet denoising as a post-processing enhancement method for non-invasive foetal electrocardiography. Comput Methods Programs Biomed 2020; 195:105558. [PMID: 32505973 DOI: 10.1016/j.cmpb.2020.105558] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 04/30/2020] [Accepted: 05/18/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND AND OBJECTIVE The detection of a clean and undistorted foetal electrocardiogram (fECG) from non-invasive abdominal recordings is an open research issue. Several physiological and instrumental noise sources hamper this process, even after that powerful fECG extraction algorithms have been used. Wavelet denoising is widely used for the improvement of the SNR in biomedical signal processing. This work aims to systematically assess conventional and unconventional wavelet denoising approaches for the post-processing of fECG signals by providing evidence of their effectiveness in improving fECG SNR while preserving the morphology of the signal of interest. METHODS The stationary wavelet transform (SWT) and the stationary wavelet packet transform (SWPT) were considered, due to their different granularity in the sub-band decomposition of the signal. Three thresholds from the literature, either conventional (Minimax and Universal) and unconventional, were selected. To this aim, the unconventional one was adapted for the first time to SWPT by trying different approaches. The decomposition depth was studied in relation to the characteristics of the fECG signal. Synthetic and real datasets, publicly available for benchmarking and research, were used for quantitative analysis in terms of noise reduction, foetal QRS detection performance and preservation of fECG morphology. RESULTS The adoption of wavelet denoising approaches generally improved the SNR. Interestingly, the SWT methods outperformed the SWPT ones in morphology preservation (p<0.04) and SNR (p<0.0003), despite their coarser granularity in the sub-band analysis. Remarkably, the Han et al. threshold, adopted for the first time for fECG processing, provided the best quality improvement (p<0.003). CONCLUSIONS The findings of our systematic analysis suggest that particular care must be taken when selecting and using wavelet denoising for non-invasive fECG signal post-processing. In particular, despite the general noise reduction capability, signal morphology can be significantly altered on the basis of the parameterization of the wavelet methods. Remarkably, the adoption of a finer sub-band decomposition provided by the wavelet packet was not able to improve the quality of the processing.
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Affiliation(s)
- Giulia Baldazzi
- DIEE, Department of Electrical and Electronic Engineering, University of Cagliari, Piazza d'Armi, 09122 Cagliari, Italy; DIBRIS, Department of Informatics, Bioengineering, Robotics and Systems Engineering, University of Genoa, Via Opera Pia 13, 16145 Genoa, Italy.
| | - Eleonora Sulas
- DIEE, Department of Electrical and Electronic Engineering, University of Cagliari, Piazza d'Armi, 09122 Cagliari, Italy
| | - Monica Urru
- Division of Paediatric Cardiology, San Michele Hospital, Piazzale Alessandro Ricchi 1, 09134 Cagliari, Italy
| | - Roberto Tumbarello
- Division of Paediatric Cardiology, San Michele Hospital, Piazzale Alessandro Ricchi 1, 09134 Cagliari, Italy
| | - Luigi Raffo
- DIEE, Department of Electrical and Electronic Engineering, University of Cagliari, Piazza d'Armi, 09122 Cagliari, Italy
| | - Danilo Pani
- DIEE, Department of Electrical and Electronic Engineering, University of Cagliari, Piazza d'Armi, 09122 Cagliari, Italy
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Arrigo A, Perra C, Aragona E, Giusto D, Doglioni C, Pierro L, Giordano Resti A, Bandello F, Battaglia Parodi M. Extrafoveal Müller cells detection in vivo in the human retina: A pilot study based on optical coherence tomography. Exp Eye Res 2020; 199:108183. [PMID: 32777210 DOI: 10.1016/j.exer.2020.108183] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 07/27/2020] [Accepted: 08/03/2020] [Indexed: 11/15/2022]
Abstract
Müller cells (MC) represent a key element for the metabolic and functional regulation of the vertebrate retina. The aim of the present study was to test the feasibility of a new method for the in-vivo detection and quantification of extrafoveal MC in human retina. We developed a new approach to isolate and analyse extrafoveal MC in vivo, starting from structural optical coherence tomography data. Our pilot investigation was based on the optical properties of MC, which are known to not interfere with the light reaching the outer retinal structures. We reconstructed MC in the macular region of 18 healthy subjects and the quantitative analyses revealed ~42,000/9 mm2 cells detected. Furthermore, we included 2 patients affected by peripheral intraocular melanoma, with macular sparing, needing surgical enucleation. We used these two eyes to perform a qualitative comparison between our reconstructions and histological findings. Our study represents the first pilot investigation dedicated on the non-invasive isolation and quantification of MC, in-vivo, in human retina. Although we are aware that our study has several limitations, first of all related with the proper detection of foveal MC, because of the peculiar z-shape morphology, this approach may open new opportunities for the non-invasive in vivo analysis of MC, providing also potential useful perspectives in retinal diseases.
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Affiliation(s)
- Alessandro Arrigo
- Department of Ophthalmology, Scientific Institute San Raffaele, Vita-Salute University, Milan, Italy.
| | - Cristian Perra
- Department of Electrical and Electronic Engineering (DIEE), CNIT Research Unit, University of Cagliari, Italy
| | - Emanuela Aragona
- Department of Ophthalmology, Scientific Institute San Raffaele, Vita-Salute University, Milan, Italy
| | - Daniele Giusto
- Department of Electrical and Electronic Engineering (DIEE), CNIT Research Unit, University of Cagliari, Italy
| | - Claudio Doglioni
- Unit of Pathology, IRCCS San Raffaele Scientific Institute, Milano, Italy
| | - Luisa Pierro
- Department of Ophthalmology, Scientific Institute San Raffaele, Vita-Salute University, Milan, Italy
| | - Antonio Giordano Resti
- Department of Ophthalmology, Scientific Institute San Raffaele, Vita-Salute University, Milan, Italy
| | - Francesco Bandello
- Department of Ophthalmology, Scientific Institute San Raffaele, Vita-Salute University, Milan, Italy
| | - Maurizio Battaglia Parodi
- Department of Ophthalmology, Scientific Institute San Raffaele, Vita-Salute University, Milan, Italy
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Jamshidi P, Aristizabal M, Kong W, Villapun V, Cox SC, Grover LM, Attallah MM. Selective Laser Melting of Ti-6Al-4V: The Impact of Post-processing on the Tensile, Fatigue and Biological Properties for Medical Implant Applications. Materials (Basel) 2020; 13:E2813. [PMID: 32580477 PMCID: PMC7345457 DOI: 10.3390/ma13122813] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 06/10/2020] [Accepted: 06/19/2020] [Indexed: 02/07/2023]
Abstract
One of the main challenges in additive manufacturing (AM) of medical implants for the treatment of bone tissue defects is to optimise the mechanical and biological performance. The use of post-processing can be a necessity to improve the physical properties of customised AM processed implants. In this study, Ti-6Al-4V coupons were manufactured using selective laser melting (SLM) in two build orientations (vertical and horizontal) and subsequently post-processed using combinations of hot isostatic pressing (HIP), sandblasting (SB), polishing (PL) and chemical etching (CE). The effect of the different post-manufacturing strategies on the tensile and fatigue performance of the SLMed parts was investigated and rationalised by observing the surface topography. Vertically built samples showed higher yield strength (YS) and ultimate tensile strength (UTS) than the horizontal samples, increasing from 760.9 ± 22.3 MPa and 961.3 ± 50.2 MPa in the horizontal condition to 820.09 ± 16.5 MPa and 1006.7 ± 6.3 MPa in the vertical condition, respectively. After the HIP treatment, the ductility was substantially improved in both orientations; by 2.1 and 2.9 folds in the vertical and horizontal orientations, respectively. The vertically built samples demonstrated a superior ductility of 22% following HIP and polishing. Furthermore, chemical etching was found to be the most effective surface post-processing treatment to improve the fatigue performance after HIP, achieving the highest run-out strength of 450 MPa. Most importantly, chemical etching after HIP enhanced the cellular affinity of the surface, in addition to its good fatigue performance, making it a promising post-processing approach for bone implants where tissue integration is needed.
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Affiliation(s)
- Parastoo Jamshidi
- School of Materials and Metallurgy, University of Birmingham, Edgbaston B15 2TT, UK; (P.J.); (W.K.)
| | - Miren Aristizabal
- Ceit, Manuel Lardizabal 15, 20018 Donostia/San Sebastián, Spain;
- Tecnun School of Engineering, Universidad de Navarra, Manuel Lardizabal 13, 20018 Donostia/San Sebastián, Spain
| | - Weihuan Kong
- School of Materials and Metallurgy, University of Birmingham, Edgbaston B15 2TT, UK; (P.J.); (W.K.)
| | - Victor Villapun
- School of Chemical Engineering, University of Birmingham, Edgbaston B15 2TT, UK; (V.V.); (S.C.C.); (L.M.G.)
| | - Sophie C. Cox
- School of Chemical Engineering, University of Birmingham, Edgbaston B15 2TT, UK; (V.V.); (S.C.C.); (L.M.G.)
| | - Liam M. Grover
- School of Chemical Engineering, University of Birmingham, Edgbaston B15 2TT, UK; (V.V.); (S.C.C.); (L.M.G.)
| | - Moataz M. Attallah
- School of Materials and Metallurgy, University of Birmingham, Edgbaston B15 2TT, UK; (P.J.); (W.K.)
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Schulz-Menger J, Bluemke DA, Bremerich J, Flamm SD, Fogel MA, Friedrich MG, Kim RJ, von Knobelsdorff-Brenkenhoff F, Kramer CM, Pennell DJ, Plein S, Nagel E. Standardized image interpretation and post-processing in cardiovascular magnetic resonance - 2020 update : Society for Cardiovascular Magnetic Resonance (SCMR): Board of Trustees Task Force on Standardized Post-Processing. J Cardiovasc Magn Reson 2020; 22:19. [PMID: 32160925 PMCID: PMC7066763 DOI: 10.1186/s12968-020-00610-6] [Citation(s) in RCA: 411] [Impact Index Per Article: 102.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 02/17/2020] [Indexed: 01/04/2023] Open
Abstract
With mounting data on its accuracy and prognostic value, cardiovascular magnetic resonance (CMR) is becoming an increasingly important diagnostic tool with growing utility in clinical routine. Given its versatility and wide range of quantitative parameters, however, agreement on specific standards for the interpretation and post-processing of CMR studies is required to ensure consistent quality and reproducibility of CMR reports. This document addresses this need by providing consensus recommendations developed by the Task Force for Post-Processing of the Society for Cardiovascular Magnetic Resonance (SCMR). The aim of the Task Force is to recommend requirements and standards for image interpretation and post-processing enabling qualitative and quantitative evaluation of CMR images. Furthermore, pitfalls of CMR image analysis are discussed where appropriate. It is an update of the original recommendations published 2013.
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Affiliation(s)
- Jeanette Schulz-Menger
- Department of Cardiology and Nephrology, Working Group on Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max-Delbrueck Center for Molecular Medicine, and HELIOS Klinikum Berlin Buch, Schwanebecker Chaussee 50, 13125, Berlin, Germany.
| | - David A Bluemke
- University of Wisconsin School of Medicine and Public Health, Madison, USA
| | - Jens Bremerich
- Department of Radiology of the University Hospital Basel, Basel, Switzerland
| | - Scott D Flamm
- Imaging, and Heart and Vascular Institutes, Cleveland Clinic, Cleveland, OH, USA
| | - Mark A Fogel
- Department of Radiology, Children's Hospital of Philadelphia, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - Matthias G Friedrich
- Departments of Medicine and Diagnostic Radiology, McGill University, Montreal, QC, Canada
| | - Raymond J Kim
- Duke Cardiovascular Magnetic Resonance Center, and Departments of Medicine and Radiology, Duke University Medical Center, Durham, NC, USA
| | | | - Christopher M Kramer
- Departments of Medicine and Radiology and the Cardiovascular Imaging Center, University of Virginia Health System, Charlottesville, VA, USA
| | | | - Sven Plein
- Leeds Institute for Genetics Health and Therapeutics & Leeds Multidisciplinary Cardiovascular Research Centre, University of Leeds, Leeds, UK
| | - Eike Nagel
- Institute for Experimental and Translational Cardiovascular Imaging, DZHK (German Centre for Cardiovascular Research) Centre for Cardiovascular Imaging, partner site RheinMain, University Hospital Frankfurt, Frankfurt am Main, Germany
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Hong SH, Goo HW, Maeda E, Choo KS, Tsai IC. User-Friendly Vendor-Specific Guideline for Pediatric Cardiothoracic Computed Tomography Provided by the Asian Society of Cardiovascular Imaging Congenital Heart Disease Study Group: Part 1. Imaging Techniques. Korean J Radiol 2019; 20:190-204. [PMID: 30672159 PMCID: PMC6342752 DOI: 10.3348/kjr.2018.0571] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Accepted: 09/30/2018] [Indexed: 12/13/2022] Open
Abstract
Optimal performance of pediatric cardiothoracic computed tomography (CT) is technically challenging and may need different approaches for different types of CT scanners. To meet the technical demands and improve clinical standards, a practical, user-friendly, and vendor-specific guideline for pediatric cardiothoracic CT needs to be developed for children with congenital heart disease (CHD). In this article, we have attempted to describe such guideline based on the consensus of experts in the Asian Society of Cardiovascular Imaging CHD Study Group. This first part describes the imaging techniques of pediatric cardiothoracic CT, and it includes recommendations for patient preparation, scan techniques, radiation dose, intravenous injection protocol, post-processing, and vendor-specific protocols.
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Affiliation(s)
- Sun Hwa Hong
- Department of Radiology, Mediplex Sejong Hospital, Incheon, Korea
| | - Hyun Woo Goo
- Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea.
| | - Eriko Maeda
- Department of Radiology, The University of Tokyo, Tokyo, Japan
| | - Ki Seok Choo
- Department of Radiology, Pusan National University Hospital, Pusan National University School of Medicine, Busan, Korea
| | - I Chen Tsai
- Congenital Heart Disease Study Group Member of the Asian Society of Cardiovascular Imaging, Taiwan
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Lam CZ, Pagano JJ, Yim D, Yoo SJ, Seed M, Grosse-Wortmann L. Mapping versus source methods for quantifying myocardial T1 in controls and in repaired tetralogy of Fallot: interchangeability and reproducibility in children. Pediatr Radiol 2019; 49:1152-1162. [PMID: 31190110 DOI: 10.1007/s00247-019-04428-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 04/03/2019] [Accepted: 05/14/2019] [Indexed: 11/27/2022]
Abstract
BACKGROUND Myocardial T1 relaxometry can be performed by contouring on individual T1-weighted source images (source method) or on a single T1 map (mapping method). OBJECTIVE This study compares (a) agreement between native T1 and extracellular volume results of the two methods and (b) interobserver reproducibility of the two methods in children without heart disease and those with tetralogy of Fallot (TOF). MATERIALS AND METHODS We retrospectively analyzed pediatric patients (controls and those with repaired TOF) with cardiac magnetic resonance examinations including extracellular volume quantification using the modified Look-Locker inversion recovery (MOLLI) sequence. We compared native T1 and extracellular volume of the entire left ventricle and interventricular septum derived using the source and the mapping approaches. RESULTS In the control group (n=25, median age 14.0 years, interquartile range [IQR] 11.5-16.5 years), the mapping method produced lower native T1 values than the source method in the interventricular septum (mean difference ± standard deviation [SD] = 12±15 ms, P<0.001). In the TOF group (n=50, median age 13.3 years, IQR 9.9-15.0 years), the mapping method produced lower values for native T1 and extracellular volume in the interventricular septum (mean difference 9±14 ms and 0.6±1.1%, P<0.001). In 6-12% of the children, differences were >3 standard deviations from the mean difference. Interobserver reproducibility between the two methods by intraclass correlation coefficients were clinically equivalent. CONCLUSION T1 and extracellular volume values generated by the source and mapping methods show systematic differences and can vary significantly in an individual child, and thus cannot be used interchangeably in clinical practice. The source method might allow for easier detection and, in some cases, mitigation of artifacts that are not infrequent in children and can be difficult to appreciate on the T1 map.
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Affiliation(s)
- Christopher Z Lam
- Department of Diagnostic Imaging, The Hospital for Sick Children, Department of Medical Imaging, University of Toronto, 555 University Ave., 2107C Burton Wing, Toronto, ON, M5G 1X8, Canada.
| | - Joseph J Pagano
- Department of Paediatrics, Division of Cardiology, The Hospital for Sick Children, University of Toronto,, Toronto, ON, Canada
| | - Deane Yim
- Department of Paediatrics, Division of Cardiology, The Hospital for Sick Children, University of Toronto,, Toronto, ON, Canada
| | - Shi-Joon Yoo
- Department of Diagnostic Imaging, The Hospital for Sick Children, Department of Medical Imaging, University of Toronto, 555 University Ave., 2107C Burton Wing, Toronto, ON, M5G 1X8, Canada
- Department of Paediatrics, Division of Cardiology, The Hospital for Sick Children, University of Toronto,, Toronto, ON, Canada
| | - Mike Seed
- Department of Diagnostic Imaging, The Hospital for Sick Children, Department of Medical Imaging, University of Toronto, 555 University Ave., 2107C Burton Wing, Toronto, ON, M5G 1X8, Canada
- Department of Paediatrics, Division of Cardiology, The Hospital for Sick Children, University of Toronto,, Toronto, ON, Canada
| | - Lars Grosse-Wortmann
- Department of Diagnostic Imaging, The Hospital for Sick Children, Department of Medical Imaging, University of Toronto, 555 University Ave., 2107C Burton Wing, Toronto, ON, M5G 1X8, Canada
- Department of Paediatrics, Division of Cardiology, The Hospital for Sick Children, University of Toronto,, Toronto, ON, Canada
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Lytvynchuk LM, Falkner-Radler CI, Krepler K, Glittenberg CG, Ahmed D, Petrovski G, Lorenz B, Ansari-Shahrezaei S, Binder S. Dynamic intraoperative optical coherence tomography for inverted internal limiting membrane flap technique in large macular hole surgery. Graefes Arch Clin Exp Ophthalmol 2019; 257:1649-59. [PMID: 31139918 DOI: 10.1007/s00417-019-04364-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 05/12/2019] [Accepted: 05/14/2019] [Indexed: 10/26/2022] Open
Abstract
BACKGROUND/OBJECTIVES To assess the efficacy of dynamic intraoperative spectral-domain optical coherence tomography (iSD-OCT) imaging for inverted internal limiting membrane (ILM) flap technique (IILMFT) in large macular hole (MH) surgery. SUBJECTS/METHODS Prospective, non-randomized, observational study was conducted on 8 eyes of 7 patients with large, chronic and recurrent MHs, which were treated by pars plana vitrectomy (PPV) with IILMFT. All patients underwent standard pre- and postoperative examination. The iSD-OCT imaging was performed using microscope integrated systems before, during, and after ILM peeling. The iSD-OCT data were post-processed using graphic software and reviewed for tissue behavior and instruments position. RESULTS The real-time iSD-OCT-assisted IILMFT allowed for real-time imaging of the entire surgery with visualization of the MH, vitreoretinal instruments, and all steps of inverted ILM flap formation. In spite of shadowing created by the steel instruments, it was possible to follow and control the distance between the instrument tips and retinal layers. Dynamic imaging of the surgical maneuvers including ILM peeling and mechanical apposition of MH edges revealed the iatrogenic impact on the retina (depression and appearance of hyporeflective zones). iSD-OCT imaging could confirm the proper position of the inverted ILM flap at the very end of the surgery after fluid-air exchange. CONCLUSIONS iSD-OCT imaging is an effective tool for learning and performing a well-controlled and safe inverted ILM flap technique in patients with large MH. Clinical significance of the structural iSD-OCT findings has to be further studied.
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Roy CW, Marini D, Segars WP, Seed M, Macgowan CK. Fetal XCMR: a numerical phantom for fetal cardiovascular magnetic resonance imaging. J Cardiovasc Magn Reson 2019; 21:29. [PMID: 31118056 PMCID: PMC6532268 DOI: 10.1186/s12968-019-0539-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 04/15/2019] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Validating new techniques for fetal cardiovascular magnetic resonance (CMR) is challenging due to random fetal movement that precludes repeat measurements. Consequently, fetal CMR development has been largely performed using physical phantoms or postnatal volunteers. In this work, we present an open-source simulation designed to aid in the development and validation of new approaches for fetal CMR. Our approach, fetal extended Cardiac-Torso cardiovascular magnetic resonance imaging (Fetal XCMR), builds on established methods for simulating CMR acquisitions but is tailored toward the dynamic physiology of the fetal heart and body. We present comparisons between the Fetal XCMR phantom and data acquired in utero, resulting in image quality, anatomy, tissue signals and contrast. METHODS Existing extended Cardiac-Torso models are modified to create maternal and fetal anatomy, combined according to simulated motion, mapped to CMR contrast, and converted to CMR data. To provide a comparison between the proposed simulation and experimental fetal CMR images acquired in utero, images from a typical scan of a pregnant woman are included and simulated acquisitions were generated using matching CMR parameters, motion and noise levels. Three reconstruction (static, real-time, and CINE), and two motion estimation methods (translational motion, fetal heart rate) from data acquired in transverse, sagittal, coronal, and short-axis planes of the fetal heart were performed to compare to in utero acquisitions and demonstrate feasibility of the proposed simulation framework. RESULTS Overall, CMR contrast, morphologies, and relative proportions of the maternal and fetal anatomy are well represented by the Fetal XCMR images when comparing the simulation to static images acquired in utero. Additionally, visualization of maternal respiratory and fetal cardiac motion is comparable between Fetal XCMR and in utero real-time images. Finally, high quality CINE image reconstructions provide excellent delineation of fetal cardiac anatomy and temporal dynamics for both data types. CONCLUSION The fetal CMR phantom provides a new method for evaluating fetal CMR acquisition and reconstruction methods by simulating the underlying anatomy and physiology. As the field of fetal CMR continues to grow, new methods will become available and require careful validation. The fetal CMR phantom is therefore a powerful and convenient tool in the continued development of fetal cardiac imaging.
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Affiliation(s)
- Christopher W. Roy
- Department of Radiology, Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Vaud Switzerland
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario Canada
- Division of Translational Medicine, Peter Gilgan Centre for Research & Learning, The Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4 Canada
| | - Davide Marini
- Division of Pediatric Cardiology, The Hospital for Sick Children, Toronto, Ontario Canada
| | - William Paul Segars
- Department of Radiology, Duke University Medical Center, Durham, North Carolina USA
| | - Mike Seed
- Division of Pediatric Cardiology, The Hospital for Sick Children, Toronto, Ontario Canada
- Departments of Pediatrics and Diagnostic Imaging, University of Toronto, Toronto, Ontario Canada
| | - Christopher K. Macgowan
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario Canada
- Division of Translational Medicine, Peter Gilgan Centre for Research & Learning, The Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4 Canada
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Hammon RA, Seuss H, Hammon M, Grillhösl C, Heiss R, Zeilinger M, Bayerl N, Vuylsteke P, Wanninger F, Schroth M, Uder M, Rompel O. Improved visualization of peripherally inserted central catheters on chest radiographs of neonates using fractional multiscale image processing. BMC Med Imaging 2019; 19:3. [PMID: 30612560 PMCID: PMC6322299 DOI: 10.1186/s12880-018-0302-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 12/26/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Peripherally inserted central catheters (PICCs) provide secure intravenous access for the delivery of life-sustaining medications and nutrition. They are commonly used in pediatrics. Confirmation of correct central catheter tip position is crucial. Verification is usually done by a radiograph. The aim of this study is to evaluate the ability of Fractional Multiscale image Processing (FMP) to detect PICC tips on the digital chest radiographs of neonates. METHODS A total of 94 radiographs of 47 patients were included in the study. 29 patients were male, 18 were female. The mean age of all examined children was 9.2 days (range 0-99 days). In total, six readers (two radiologists, two residents in radiology, one last year medical student, one neonatologist) evaluated 94 unprocessed and catheter-enhanced radiographs using a 5-point Likert scale (1 = poor catheter tip visualization, 5 = excellent catheter tip visualization). Additionally, the two radiologists evaluated the diagnostic confidence for chest pathologies using a 5-point Likert scale (1 = poor diagnostic confidence, 5 = excellent diagnostic confidence). Radiographs were evaluated on a dedicated workstation. RESULTS In all cases, the catheter-enhanced radiograph rated higher than (n = 471), or equal (n = 93) to, the unprocessed radiograph when visualizing catheter tips. 87% of the catheter-enhanced radiographs obtained a rating of 4 or higher, while only 42% of unprocessed radiographs received 4 or more points. Regarding diagnostic confidence for chest pathologies one radiologist rated two catheter-enhanced radiographs higher than the unprocessed radiographs, while all other 186 evaluations rated the catheter-enhanced radiographs equal to (n = 78) or lower than (n = 108) the unprocessed radiographs. Only 60% of the catheter-enhanced radiographs yielded a diagnostic confidence of 4 or higher, while 90% of the unprocessed images received 4 or more points. CONCLUSION Catheter-enhanced digital chest radiographs demonstrate improved visualization of low contrast PICC tips in neonates compared to unprocessed radiographs. Furthermore, they enable detection of accompanying chest pathologies. However, definitive diagnosis of chest pathologies should be made on unprocessed radiographs.
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Affiliation(s)
- Rebecca A Hammon
- Department of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Maximiliansplatz 3, 91054, Erlangen, Germany
| | - Hannes Seuss
- Department of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Maximiliansplatz 3, 91054, Erlangen, Germany
| | - Matthias Hammon
- Department of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Maximiliansplatz 3, 91054, Erlangen, Germany.
| | - Christian Grillhösl
- Department of Neonatology and Pediatric Intensive Care, Cnopf Children's Hospital, Sankt-Johannis-Mühlgasse 19, 90419, Nürnberg, Germany
| | - Rafael Heiss
- Department of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Maximiliansplatz 3, 91054, Erlangen, Germany
| | - Martin Zeilinger
- Department of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Maximiliansplatz 3, 91054, Erlangen, Germany
| | - Nadine Bayerl
- Department of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Maximiliansplatz 3, 91054, Erlangen, Germany
| | | | | | - Michael Schroth
- Department of Neonatology and Pediatric Intensive Care, Cnopf Children's Hospital, Sankt-Johannis-Mühlgasse 19, 90419, Nürnberg, Germany
| | - Michael Uder
- Department of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Maximiliansplatz 3, 91054, Erlangen, Germany
| | - Oliver Rompel
- Department of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Maximiliansplatz 3, 91054, Erlangen, Germany
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Abstract
We present a very unusual case of an accessory articulation of the transverse processes of C6 and C7. Only four previous cases have been described in English literature. Our case stresses the importance of computed tomography (CT) and post-processing images to discriminate this variant from posttraumatic or degenerative lesions. Multiplanar reformations and volume-rendered images should be added to the cervical spine CT protocol.
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Shi Y, Zeng W, Wang N. SCGICAR: Spatial concatenation based group ICA with reference for fMRI data analysis. Comput Methods Programs Biomed 2017; 148:137-151. [PMID: 28774436 DOI: 10.1016/j.cmpb.2017.07.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 05/21/2017] [Accepted: 07/03/2017] [Indexed: 06/07/2023]
Abstract
BACKGROUND AND OBJECTIVE With the rapid development of big data, the functional magnetic resonance imaging (fMRI) data analysis of multi-subject is becoming more and more important. As a kind of blind source separation technique, group independent component analysis (GICA) has been widely applied for the multi-subject fMRI data analysis. However, spatial concatenated GICA is rarely used compared with temporal concatenated GICA due to its disadvantages. METHODS In this paper, in order to overcome these issues and to consider that the ability of GICA for fMRI data analysis can be improved by adding a priori information, we propose a novel spatial concatenation based GICA with reference (SCGICAR) method to take advantage of the priori information extracted from the group subjects, and then the multi-objective optimization strategy is used to implement this method. Finally, the post-processing means of principal component analysis and anti-reconstruction are used to obtain group spatial component and individual temporal component in the group, respectively. RESULTS The experimental results show that the proposed SCGICAR method has a better performance on both single-subject and multi-subject fMRI data analysis compared with classical methods. It not only can detect more accurate spatial and temporal component for each subject of the group, but also can obtain a better group component on both temporal and spatial domains. CONCLUSIONS These results demonstrate that the proposed SCGICAR method has its own advantages in comparison with classical methods, and it can better reflect the commonness of subjects in the group.
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Affiliation(s)
- Yuhu Shi
- Lab of Digital Image and Intelligent Computation, Shanghai Maritime University, 1550 Harbor Avenue, Pudong, Shanghai, 201306, China
| | - Weiming Zeng
- Lab of Digital Image and Intelligent Computation, Shanghai Maritime University, 1550 Harbor Avenue, Pudong, Shanghai, 201306, China.
| | - Nizhuan Wang
- Neuroimaging Lab, School of Biomedical Engineering, Health Science Center, Shenzhen University, Shenzhen 518060, China; Guangdong Key Laboratory of Biomedical Information Detection and Ultrasound Imaging, Shenzhen 518060, China
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Kampf T, Bauer WR, Reiter T. Improved post-processing strategy for MOLLI based tissue characterization allows application in patients with dyspnoe and impaired left ventricular function. Z Med Phys 2017; 28:25-35. [PMID: 28801204 DOI: 10.1016/j.zemedi.2017.07.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 07/13/2017] [Accepted: 07/13/2017] [Indexed: 10/19/2022]
Abstract
Contrast and non-contrast MRI based characterization of myocardium by T1-mapping will be of paramount importance to obtain biomarkers, e.g. fibrosis, which determines the risk of heart failure patients. T1-mapping by the standard post-processing of the modified look-locker inversion recovery (MOLLI) lacks of accuracy when trying to reduce its duration, which on the other hand, is highly desirable in patients with heart failure. The recently suggested inversion group fitting (IGF) technique, which considers more parameters for fitting, has a superior accuracy for long T1 times despite a shorter duration. However, for short T1 values, the standard method has a superior precision. A conditional fitting routine is proposed which ideally takes advantage of both algorithms. MATERIALS AND METHODS All measurements were performed on a 1.5T clinical scanner (ACHIEVA, Philips Healthcare, The Netherlands) using a MOLLI 5(n)3(n)3 prototype with n(heart beats) being a variable waiting time between inversion experiments. Phantom experiments covered a broad range of T1 times, waiting times and heart rates. A saturation recovery experiment served as a gold standard for T1 measurement. All data were analyzed with the standard MOLLI, the IGF fit and the conditional fitting routine and the obtained T1 values were compared with the gold standard. In vivo measurements were performed in a healthy volunteer and a total of 34 patients with normal findings, dilative cardiomyopathy and amyloidosis. RESULTS Theoretical analysis and phantom experiments provided a threshold value for an apparent IGF T1* determining processing with IGF post processing for values above, or switching to the standard technique for values below. This was validated in phantoms and patients measurements. A reduction of the waiting time to 1 instead of 3 heart beats between the inversion experiments showed reliable results. The acquisition time was reduced from 17 to 13 heart beats. The in vivo measurements showed ECV values between 25% (18-33%; SD 0.03) in the healthy, 30% (22-40%; SD 0.04) in patients with DCM and 45% (30-60%; SD 0.9) in patients with amyloidosis. CONCLUSION The adopted post-processing algorithm determines long T1 values with high accuracy and short T1 values while maintaining a high precision. Based on reduction of waiting time, and independence of heart rate, it shortens breath hold duration and allows fast T1-mapping, which is frequently a prerequisite in patients with cardiac diseases.
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Affiliation(s)
- Thomas Kampf
- University of Wuerzburg, Department for Experimental Physics V, Am Hubland, 97074 Wuerzburg, Germany; Comprehensive Heart Failure Centre Wuerzburg, Germany.
| | - Wolfgang Rudolf Bauer
- University Hospital Wuerzburg, Department of Internal Medicine I, Oberduerrbacher Straße 6a, 97080 Wuerzburg, Germany; Comprehensive Heart Failure Centre Wuerzburg, Germany.
| | - Theresa Reiter
- University Hospital Wuerzburg, Department of Internal Medicine I, Oberduerrbacher Straße 6a, 97080 Wuerzburg, Germany; Comprehensive Heart Failure Centre Wuerzburg, Germany.
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Broche LM, Ross PJ, Davies GR, Lurie DJ. Simple algorithm for the correction of MRI image artefacts due to random phase fluctuations. Magn Reson Imaging 2017; 44:55-59. [PMID: 28751203 DOI: 10.1016/j.mri.2017.07.023] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 07/23/2017] [Indexed: 10/19/2022]
Abstract
PURPOSE Fast Field-Cycling (FFC) MRI is a novel technology that allows varying the main magnetic field B0 during the pulse sequence, from the nominal field (usually hundreds of millitesla) down to Earth's field or below. This technique uses resistive magnets powered by fast amplifiers. One of the challenges with this method is to stabilise the magnetic field during the acquisition of the NMR signal. Indeed, a typical consequence of field instability is small, random phase variations between each line of k-space resulting in artefacts, similar to those which occur due to homogeneous motion but harder to correct as no assumption can be made about the phase error, which appears completely random. Here we propose an algorithm that can correct for the random phase variations induced by field instabilities without prior knowledge about the phase error. METHODS The algorithm exploits the fact that ghosts caused by field instability manifest in image regions which should be signal free. The algorithm minimises the signal in the background by finding an optimum phase correction for each line of k-space and repeats the operation until the result converges, leaving the background free of signal. CONCLUSION We showed the conditions for which the algorithm is robust and successfully applied it on images acquired on FFC-MRI scanners. The same algorithm can be used for various applications other than Fast Field-Cycling MRI.
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Affiliation(s)
- Lionel M Broche
- Aberdeen Biomedical Imaging Centre, School of Medicine and Dentistry, University of Aberdeen, Scotland, UK.
| | - P James Ross
- Aberdeen Biomedical Imaging Centre, School of Medicine and Dentistry, University of Aberdeen, Scotland, UK
| | - Gareth R Davies
- Aberdeen Biomedical Imaging Centre, School of Medicine and Dentistry, University of Aberdeen, Scotland, UK
| | - David J Lurie
- Aberdeen Biomedical Imaging Centre, School of Medicine and Dentistry, University of Aberdeen, Scotland, UK
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Pastor G, Jiménez-González M, Plaza-García S, Beraza M, Padro D, Ramos-Cabrer P, Reese T. A general protocol of ultra-high resolution MR angiography to image the cerebro-vasculature in 6 different rats strains at high field. J Neurosci Methods 2017; 289:75-84. [PMID: 28694213 DOI: 10.1016/j.jneumeth.2017.07.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 07/06/2017] [Accepted: 07/06/2017] [Indexed: 11/23/2022]
Abstract
BACKGROUND Differences in the cerebro-vasculature among strains as well as individual animals might explain variability in animal models and thus, a non-invasive method tailored to image cerebral vessel of interest with high signal to noise ratio is required. NEW METHOD Experimentally, we describe a new general protocol of three-dimensional time-of-flight magnetic resonance angiography to visualize non-invasively the cerebral vasculature in 6 different rat strains. Flow compensated angiograms of Sprague Dawley, Wistar Kyoto, Lister Hooded, Long Evans, Fisher 344 and Spontaneous Hypertensive Rat strains were obtained without the use of contrast agents. At 11.7T using a repetition time of 60ms, an isotropic resolution of up to 62μm was achieved; total imaging time was 98min for a 3D data set. RESULTS The visualization of the cerebral arteries was improved by removing extra-cranial vessels prior to the calculation of maximum intensity projection to obtain the angiograms. Ultimately, we demonstrate that the newly implemented method is also suitable to obtain angiograms following middle cerebral artery occlusion, despite the presence of intense vasogenic edema 24h after reperfusion. COMPARISON WITH EXISTING METHODS The careful selection of the excitation profile and repetition time at a higher static magnetic field allowed an increase in spatial resolution to reliably detect of the hypothalamic artery, the anterior choroidal artery as well as arterial branches of the peri-amygdoidal complex and the optical nerve in six different rat strains. CONCLUSIONS MR angiography without contrast agent can be utilized to study cerebro-vascular abnormalities in various animal models.
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Kondratov AV, Rogov OY, Gainutdinov RV. AFM reconstruction of complex-shaped chiral plasmonic nanostructures. Ultramicroscopy 2017; 181:81-85. [PMID: 28527313 DOI: 10.1016/j.ultramic.2017.05.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 05/04/2017] [Accepted: 05/10/2017] [Indexed: 11/30/2022]
Abstract
A significant part of the optical metamaterial phenomena has the plasmonic nature and their investigation requires very accurate knowledge of the fabricated structures shape with a focus on the periodical features. We describe a consistent approach to the shape reconstruction of the plasmonic nanostructures. This includes vertical and tilted spike AFM probes fabrication, AFM imaging and specific post-processing. We studied a complex-shaped chiral metamaterial and conclude that the described post-processing routine extends possibilities of the existing deconvolution algorithms in the case of periodical structures with known rotational symmetry, by providing valuable information about periodical features.
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Affiliation(s)
- A V Kondratov
- Shubnikov Institute of Crystallography of Federal Scientific Research Centre "Crystallography and Photonics" of Russian Academy of Sciences, 119333 Moscow, Russia.
| | - O Y Rogov
- Shubnikov Institute of Crystallography of Federal Scientific Research Centre "Crystallography and Photonics" of Russian Academy of Sciences, 119333 Moscow, Russia
| | - R V Gainutdinov
- Shubnikov Institute of Crystallography of Federal Scientific Research Centre "Crystallography and Photonics" of Russian Academy of Sciences, 119333 Moscow, Russia
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Hilber I, Mayer P, Gouliarmou V, Hale SE, Cornelissen G, Schmidt HP, Bucheli TD. Bioavailability and bioaccessibility of polycyclic aromatic hydrocarbons from (post-pyrolytically treated) biochars. Chemosphere 2017; 174:700-707. [PMID: 28199946 DOI: 10.1016/j.chemosphere.2017.02.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 01/23/2017] [Accepted: 02/03/2017] [Indexed: 05/27/2023]
Abstract
Bioaccessibility data of PAHs from biochar produced under real world conditions is scarce and the influence of feedstock and various post-pyrolysis treatments common in agriculture, such as co-composting or lacto-fermentation to produce silage fodder, on their bioavailability and bioaccessibility has hardly been studied. The total (Ctotal), and freely dissolved (i.e., bioavailable) concentrations (Cfree) of the sum of 16 US EPA PAHs of 43 biochar samples produced and treated in such ways ranged from 0.4 to almost 2000 mg/kg, and from 12 to 81 ng/L, respectively, which resulted in very high biochar-water partition coefficients (4.2 ≤ log KD ≤ 8.8 L/kg) for individual PAHs. Thirty three samples were incubated in contaminant traps that combined a diffusive carrier and a sorptive sink. Incubations yielded samples only containing desorption-resistant PAHs (Cres). The desorption resistant PAH fraction was dominant, since only eight out of 33 biochar samples showed statistically significant bioaccessible fractions (fbioaccessible = 1 - Cres/Ctotal). Bioavailability correlated positively with Ctotal/surface area. Other relationships of bioavailability and -accessibility with the investigated post-pyrolysis processes or elemental composition could not be found. PAH exposure was very limited (low Cfree, high Cres) for all samples with low to moderate Ctotal, whereas higher exposure was determined in some biochars with Ctotal > 10 mg/kg.
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Affiliation(s)
- Isabel Hilber
- Agroscope, Reckenholzstrasse 191, 8046, Zurich, Switzerland
| | - Philipp Mayer
- Department of Environmental Engineering, DTU Environment, Technical University of Denmark, Bygningstorvet B115, 2800, Kgs. Lyngby, Denmark
| | - Varvara Gouliarmou
- Department of Environmental Science, Aarhus University, Frederiksborgvej 399, 4000, Roskilde, Denmark
| | - Sarah E Hale
- Department of Environmental Engineering, Norwegian Geotechnical Institute NGI, P.O. Box 3930 Ullevål Stadion, 0806, Oslo, Norway
| | - Gerard Cornelissen
- Department of Environmental Engineering, Norwegian Geotechnical Institute NGI, P.O. Box 3930 Ullevål Stadion, 0806, Oslo, Norway; Department of Environmental Sciences (IMV), Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432, Ås, Norway; Department of Applied Environmental Sciences (ITM), Stockholm University, 10691, Sweden
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Nickander J, Lundin M, Abdula G, Sörensson P, Rosmini S, Moon JC, Kellman P, Sigfridsson A, Ugander M. Blood correction reduces variability and gender differences in native myocardial T1 values at 1.5 T cardiovascular magnetic resonance - a derivation/validation approach. J Cardiovasc Magn Reson 2017; 19:41. [PMID: 28376820 PMCID: PMC5381013 DOI: 10.1186/s12968-017-0353-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 03/14/2017] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Myocardial native T1 measurements are likely influenced by intramyocardial blood. Since blood T1 is both variable and longer compared to myocardial T1, this will degrade the precision of myocardial T1 measurements. Precision could be improved by correction, but the amount of correction and the optimal blood T1 variables to correct with are unknown. We hypothesized that an appropriate correction would reduce the standard deviation (SD) of native myocardial T1. METHODS Consecutive patients (n = 400) referred for CMR with known or suspected heart disease were split into a derivation cohort for model construction (n = 200, age 51 ± 18 years, 50% male) and a validation cohort for assessing model performance (n = 200, age 48 ± 17 years, 50% male). Exclusion criteria included focal septal abnormalities. A Modified Look-Locker inversion recovery sequence (MOLLI, 1.5 T Siemens Aera) was used to acquire T1 and T1* maps. T1 and T1* maps were used to measure native myocardial T1, and blood T1 and T1*. A multivariate linear regression correction model was implemented using blood measurement of R1 (1/T1), R1* (1/T1*) or hematocrit. The correction model from the derivation cohort was applied to the validation cohort, and assessed for reduction in variability with the F-test. RESULTS Blood [LV + RV] mean R1, mean R1* and hematocrit correlated with myocardial T1 (Pearson's r, range 0.37 to 0.45, p < 0.05 for all) in both the derivation and validation cohorts respectively, suggesting that myocardial T1 measurements are influenced by intramyocardial blood. Mean myocardial native T1 did not differ between the derivation and validation cohorts (1030 ± 42.6 ms and 1023 ± 45.2 ms respectively, p = 0.07). In the derivation cohort, correction using blood mean R1 and mean R1* yielded a decrease in myocardial T1 SD (45.2 ms to 36.6 ms, p = 0.03). When the model from the derivation cohort was applied to the validation cohort, the SD reduction was maintained (39.3 ms, p = 0.049). This 13% reduction in measurement variability leads to a 23% reduction in sample size to detect a 50 ms difference in native myocardial T1. CONCLUSIONS Correcting native myocardial T1 for R1 and R1* of blood improves the precision of myocardial T1 measurement by ~13%, and could consequently improve disease detection and reduce sample size needs for clinical research.
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Affiliation(s)
- Jannike Nickander
- Department of Clinical Physiology, Karolinska Institutet and Karolinska University Hospital, Stockholm, Sweden
| | - Magnus Lundin
- Department of Clinical Physiology, Karolinska Institutet and Karolinska University Hospital, Stockholm, Sweden
| | - Goran Abdula
- Department of Clinical Physiology, Karolinska Institutet and Karolinska University Hospital, Stockholm, Sweden
| | - Peder Sörensson
- Department of Medicine, Unit of Cardiology, Karolinska Institutet and Karolinska University Hospital, Stockholm, Sweden
| | - Stefania Rosmini
- Institute of Cardiovascular Science, University College London, London, UK
| | - James C. Moon
- Institute of Cardiovascular Science, University College London, London, UK
| | - Peter Kellman
- National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD USA
| | - Andreas Sigfridsson
- Department of Clinical Physiology, Karolinska Institutet and Karolinska University Hospital, Stockholm, Sweden
| | - Martin Ugander
- Department of Clinical Physiology, Karolinska Institutet and Karolinska University Hospital, Stockholm, Sweden
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Roy CW, Seed M, Kingdom JC, Macgowan CK. Motion compensated cine CMR of the fetal heart using radial undersampling and compressed sensing. J Cardiovasc Magn Reson 2017; 19:29. [PMID: 28316282 PMCID: PMC5357808 DOI: 10.1186/s12968-017-0346-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2016] [Accepted: 02/18/2017] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND To develop and evaluate a reconstruction framework for high resolution time-resolved CMR of the fetal heart in the presence of motion. METHODS Data were acquired using a golden angle radial trajectory in seven fetal subjects and reconstructed as real-time images to detect fetal movement. Data acquired during through-plane motion were discarded whereas in-plane motion was corrected. A fetal cardiac gating signal was extracted to sort the corrected data by cardiac phase, allowing reconstruction of cine images. The quality of motion corrected images and the effect of data undersampling were quantified using separate expressions for spatial blur and image error. RESULTS Motion corrected reordered cine reconstructions (127 slices) showed improved image quality relative to both uncorrected cines and corresponding real-time images across a range of root-mean-squared (RMS) displacements (0.3-3.7 mm) and fetal heart rates (119-176 bpm). The relative spatial blur between cines with and without motion correction increased with in-plane RMS displacement leading to an effective decrease in the effective spatial resolution for images without motion correction. Image error between undersampled and reference images was less than 10% for reconstructions using 750 or more spokes, yielding a minimum acceptable scan time of approximately 4 s/slice during quiescent through plane motion. CONCLUSIONS By rejecting data corrupted by through-plane motion, and correcting data corrupted by in-plane translation, the proposed reconstruction framework accounts for common sources of motion artifact (gross fetal movement, maternal respiration, fetal cardiac contraction) to produce high quality images of the fetal heart.
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Affiliation(s)
- Christopher W. Roy
- Department of Medical Biophysics, University of Toronto, Toronto, ON Canada
- Division of Physiology and Experimental Medicine, The Hospital for Sick Children, Toronto, ON Canada
| | - Mike Seed
- Division of Pediatric Cardiology, The Hospital for Sick Children, Toronto, ON Canada
- Departments of Pediatrics and Diagnostic Imaging, University of Toronto, Toronto, ON Canada
| | - John C. Kingdom
- Department of Obstetrics and Gynaecology, Mount Sinai Hospital, Toronto, ON Canada
- Department of Obstetrics and Gynaecology, University of Toronto, Toronto, ON Canada
| | - Christopher K. Macgowan
- Department of Medical Biophysics, University of Toronto, Toronto, ON Canada
- Division of Physiology and Experimental Medicine, The Hospital for Sick Children, Toronto, ON Canada
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Westermaier T, Linsenmann T, Homola GA, Loehr M, Stetter C, Willner N, Ernestus RI, Solymosi L, Vince GH. 3D rotational fluoroscopy for intraoperative clip control in patients with intracranial aneurysms--assessment of feasibility and image quality. BMC Med Imaging 2016; 16:30. [PMID: 27094510 PMCID: PMC4837534 DOI: 10.1186/s12880-016-0133-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 04/12/2016] [Indexed: 12/29/2022] Open
Abstract
Background Mobile 3D fluoroscopes have become increasingly available in neurosurgical operating rooms. In this series, the image quality and value of intraoperative 3D fluoroscopy with intravenous contrast agent for the evaluation of aneurysm occlusion and vessel patency after clip placement was assessed in patients who underwent surgery for intracranial aneurysms. Materials and methods Twelve patients were included in this retrospective analysis. Prior to surgery, a 360° rotational fluoroscopy scan was performed without contrast agent followed by another scan with 50 ml of intravenous iodine contrast agent. The image files of both scans were transferred to an Apple PowerMac® workstation, subtracted and reconstructed using OsiriX® free software. The procedure was repeated after clip placement. Both image sets were compared for assessment of aneurysm occlusion and vessel patency. Results Image acquisition and contrast administration caused no adverse effects. Image quality was sufficient to follow the patency of the vessels distal to the clip. Metal artifacts reduce the assessability of the immediate vicinity of the clip. Precise image subtraction and post-processing can reduce metal artifacts and make the clip-site assessable and depict larger neck-remnants. Conclusion This technique quickly supplies images at adequate quality to evaluate distal vessel patency after aneurysm clipping. Significant aneurysm remnants may be depicted as well. As it does not require visual control of all vessels that are supposed to be evaluated intraoperatively, this technique may be complementary to other intraoperative tools like indocyanine green videoangiography and micro-Doppler, especially for the assessment of larger aneurysms. At the momentary state of this technology, it cannot replace postoperative conventional angiography. However, 3D fluoroscopy and image post-processing are young technologies. Further technical developments are likely to result in improved image quality.
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Affiliation(s)
- Thomas Westermaier
- Department of Neurosurgery, University of Wuerzburg, Josef-Schneider-Str. 11, 97080, Wuerzburg, Germany.
| | - Thomas Linsenmann
- Department of Neurosurgery, University of Wuerzburg, Josef-Schneider-Str. 11, 97080, Wuerzburg, Germany
| | - György A Homola
- Department of Neuroradiology, University of Wuerzburg, Josef-Schneider-Str. 11, 97080, Wuerzburg, Germany
| | - Mario Loehr
- Department of Neurosurgery, University of Wuerzburg, Josef-Schneider-Str. 11, 97080, Wuerzburg, Germany
| | - Christian Stetter
- Department of Neurosurgery, University of Wuerzburg, Josef-Schneider-Str. 11, 97080, Wuerzburg, Germany
| | - Nadine Willner
- Department of Neurosurgery, University of Wuerzburg, Josef-Schneider-Str. 11, 97080, Wuerzburg, Germany
| | - Ralf-Ingo Ernestus
- Department of Neurosurgery, University of Wuerzburg, Josef-Schneider-Str. 11, 97080, Wuerzburg, Germany
| | - Laszlo Solymosi
- Department of Neuroradiology, University of Wuerzburg, Josef-Schneider-Str. 11, 97080, Wuerzburg, Germany
| | - Giles H Vince
- Abteilung für Neurochirurgie, Klinikum Klagenfurt, Feschnigstraße 11, 9020, Klagenfurt am Woerthersee, Austria
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