Abstract WP55: Through Thick and Thin: Improved Aspects Grading and Dense Vessel Detection Using Simple Ncct Post-processing

Stroke ◽  
2017 ◽  
Vol 48 (suppl_1) ◽  
Author(s):  
James W Evans ◽  
Sadanand Dey ◽  
Muneer Eesa ◽  
Prasanna Eswaradass ◽  
Ronda Lun ◽  
...  
Keyword(s):  
Maximum Intensity Projection ◽  
Improve Patient Care ◽  
Weighted Kappa ◽  
Slice Thickness ◽  
Post Processing ◽  
Rater Reliability ◽  
Thin Slice ◽  
Vessel Detection ◽  
Contrast Ct ◽  
Processing Techniques

Introduction: Assessing Alberta Stroke Program Early CT Score (ASPECTS) and identifying hyperdense arteries on non-contrast CT (NCCT) are important components of decision-making in acute stroke. Conventional practice uses 5mm averaged slice thickness NCCT for interpretation of these features. We have systematically evaluated several post processing techniques on NCCT to determine if there is improved reliability in identification of ASPECTS and hyperdense artery. Methodology: We assessed four post-processing techniques on NCCT namely (1) 5mm averaged thickness (2) Minimum Intensity Projection (mIP) - 5mm thickness (3) thin slices (0.625mm) and (4) Maximum Intensity Projection (MIP) - 5mm thickness (Figure 1). Three raters (student, fellow and expert) independently assessed 100 NCCT scans from the PRoveIT database. All scans were read at four different times 10-14 days apart. At each time-point the post processing modality was changed and the patient order randomized. Information on side of suspected infarction was provided. Raters were asked to score ASPECTS and identify presence of hyperdense artery at each reading. Inter-rater reliability was assessed using Intra-cluster correlation (ICC) for ASPECTS and weighted kappa (wKap) for hyperdense artery. Results: The highest inter-rater reliability was found with the MIP technique (ICC 0.42; p<0.001), followed by 5 mm average, mIP and thin slice respectively (ICC 0.33, 0.32, 0.20; all p<0.01). Highest agreement for hyperdense vessel detection was noted with thin slice (wKap 0.30; p<0.001) followed by Average, MIPs and mIPs respectively (wKap 0.25, 0.18, 0.13; all p <0.05). Conclusion: The use of MIP images for ASPECTS grading and thin images for hyperdense vessel detection improves reliability on NCCT. These simple processing steps are easily available on any modern scanner and may help improve patient care.

Abstract WP49: Performance of CT, CTA, and MRI on Decision to Treat Emergent Large Vessel Occlusion (ELVO) in Patients who Present Greater Than 6 Hours After Stroke Onset

Stroke ◽  
2017 ◽  
Vol 48 (suppl_1) ◽  
Author(s):  
Eleanor L DiBiasio ◽  
Ryan A McTaggart ◽  
Grayson L Baird ◽  
Shadi Yaghi ◽  
Eric L Tung ◽  
...  
Keyword(s):  
Mixed Model ◽  
Weighted Kappa ◽  
Stroke Onset ◽  
Lesion Volume ◽  
Diffusion Weighted Mri ◽  
Vessel Occlusion ◽  
Rater Reliability ◽  
Diffusion Weighted ◽  
Contrast Ct ◽  
The Impact

Background and purpose: We compared the value of Alberta Stroke Program Early Computed Tomographic scoring using CT (CT ASPECTS), collateral score on CT angiography (CTA), ASPECTS using diffusion-weighted MRI (DWI ASPECTS), DWI lesion volume, and DWI volume with National Institute of Health Stroke Scale (NIHSS) in determining candidacy of patients who presented >6 hours from stroke onset. Methods: Decision to treat was first determined for each test alone and then with knowledge from other tests. A dismantling design was used to determine the additive effects of each test. Any discrepancy between the first and subsequent decisions to treat, in terms of sensitivity and specificity, is the impact of gained knowledge and was assessed using a generalized mixed-model assuming a binary distribution with PROC GLIMMIX/SAS. Inter-rater reliability was examined using weighted-Kappa. Results: We identified 39 patients between December 1st, 2015 and June 30th 2016. Median time from last-known normal to non-contrast CT was 492 minutes. Median interval between non-contrast CT and CTA was 7 minutes, and between CTA and MRI, 75.5 minutes. For sensitivity, effect of knowledge gained from successive tests was not significant (Table 1; Fig. 1). However, significant gains in specificity were observed from successive tests (63% to 84%; p<.01). In particular, specificity increased by 14% (p=.09), 18% (p=.02), and 12% (p=.07), for DWI ASPECTS, DWI Volume, and DWI Volume+NIHSS, respectively. Inter-rater reliability was between .34-1.0 for each test. Conclusion: CT, CTA and MRI each have the ability to correctly determine ELVO patients who would be candidates for embolectomy. However, identification of poor candidates for endovascular therapy was significantly improved using diffusion-weighted MRI.

Analisis Informasi Citra Anatomi Vaskular dengan Multi Planar Reformating (MPR) dan Maximum Intensity Projection (MIP) pada Fase Early Arteri Pemeriksaan MSCT Abdomen

2017 ◽  
Vol 3 (2) ◽  
pp. 240-244
Author(s):  
Ratna Istiningrum ◽  
Fatimah Fatimah ◽  
Tri Wulanhandarini
Keyword(s):  
Maximum Intensity Projection ◽  
Arterial Phase ◽  
P Value ◽  
Post Processing ◽  
Test Analysis ◽  
Vascular Abnormalities ◽  
Kappa Test ◽  
Anatomical Image ◽  
Parametric Statistical Test ◽  
Early Arterial Phase

Background: The development in the field of image reconstruction is growing rapidly along with the development of  CT Scan. In  the early stages of  MSCT abdominal artery is usually found  various kinds of vascular abnormalities such as stenosis, aneurism and others. Post processing image techniques commonly used include MPR and MIP. The purpose of this study is to determine whether there is a difference between MPR and MIP techniques and to know which one is better between the two.Methods: This  research was  quantitative study with experimental approach. The study was conducted at Bhakti Dharma Husada Surabaya Hospital  with 15 samples by performing reconstruction on vascular anatomical image of coronal examination of  abdominal MSCT. Assessment of anatomical information data is done by 2 respondents. Data analysis was done by kappa test followed by Wilcoxon sign rank test.Result : The results showed the difference between the post-processing of MIP and MPR on the coronal stages of the early arterial phase of the abdominal MSCT examination, based on the results of  non-parametric statistical test analysis (Wilcoxon) showed  a significant value of p value = 0.001. The result of MIP mean rank value (8,46) is higher than the mean rank value of MPR (1,50), it can be known that post proceeding MIP technique on coronal phase cuts early arterial examination of abdominal MSCT produces better anatomical image information.Conclusion: On examination of abdominal MSCT in the early arterial phase should be at the time of processing the image is also done by using post-processing MIP because more clearly than the MPR.

scholarly journals Post-Processing Techniques for the Improvement of Liposome Stability

Pharmaceutics ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1023
Author(s):  
Ji Young Yu ◽  
Piyanan Chuesiang ◽  
Gye Hwa Shin ◽  
Hyun Jin Park
Keyword(s):  
Freeze Drying ◽  
Protective Agent ◽  
Post Processing ◽  
Additional Process ◽  
Spray Freeze Drying ◽  
The Stability ◽  
Processing Techniques ◽  
The Impact ◽  
Self Aggregation ◽  
Liposome Stability

Liposomes have been utilized as a drug delivery system to increase the bioavailability of drugs and to control the rate of drug release at the target site of action. However, the occurrence of self-aggregation, coalescence, flocculation and the precipitation of aqueous liposomes during formulation or storage can cause degradation of the vesicle structure, leading to the decomposition of liposomes. To increase the stability of liposomes, post-processing techniques have been applied as an additional process to liposomes after formulation to remove water and generate dry liposome particles with a higher stability and greater accessibility for drug administration in comparison with aqueous liposomes. This review covers the effect of these techniques including freeze drying, spray drying and spray freeze drying on the stability, physicochemical properties and drug encapsulation efficiency of dry liposomes. The parameters affecting the properties of liposomes during the drying process are also highlighted in this review. In addition, the impact of using a protective agent to overcome such limitations of each process is thoroughly discussed through various studies.

Are the Naranjo Criteria Reliable and Valid for Determination of Adverse Drug Reactions in the Intensive Care Unit?

2005 ◽  
Vol 39 (11) ◽  
pp. 1823-1827 ◽  
Author(s):  
Sandra L Kane-Gill ◽  
Levent Kirisci ◽  
Dev S Pathak
Keyword(s):  
Intensive Care Unit ◽  
Intensive Care ◽  
Adverse Drug Reactions ◽  
Reliability And Validity ◽  
Kappa Statistic ◽  
Weighted Kappa ◽  
Drug Reactions ◽  
Rater Reliability ◽  
Cronbach Alpha

BACKGROUND The Naranjo criteria are frequently used for determination of causality for suspected adverse drug reactions (ADRs); however, the psychometric properties have not been studied in the critically ill. OBJECTIVE To evaluate the reliability and validity of the Naranjo criteria for ADR determination in the intensive care unit (ICU). METHODS All patients admitted to a surgical ICU during a 3-month period were enrolled. Four raters independently reviewed 142 suspected ADRs using the Naranjo criteria (review 1). Raters evaluated the 142 suspected ADRs 3–4 weeks later, again using the Naranjo criteria (review 2). Inter-rater reliability was tested using the kappa statistic. The weighted kappa statistic was calculated between reviews 1 and 2 for the intra-rater reliability of each rater. Cronbach alpha was computed to assess the inter-item consistency correlation. The Naranjo criteria were compared with expert opinion for criterion validity for each rater and reported as a Spearman rank (rs) coefficient. RESULTS The kappa statistic ranged from 0.14 to 0.33, reflecting poor inter-rater agreement. The weighted kappa within raters was 0.5402–0.9371. The Cronbach alpha ranged from 0.443 to 0.660, which is considered moderate to good. The rs coefficient range was 0.385–0.545; all rs coefficients were statistically significant (p < 0.05). CONCLUSIONS Inter-rater reliability is marginal; however, within-rater evaluation appears to be consistent. The inter-item correlation is expected to be higher since all questions pertain to ADRs. Overall, the Naranjo criteria need modification for use in the ICU to improve reliability, validity, and clinical usefulness.

scholarly journals Post-Processing Techniques to Enhance the Quality of Metallic Parts Produced by Additive Manufacturing

Metals ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 77
Author(s):  
Muhammad Arif Mahmood ◽  
Diana Chioibasu ◽  
Asif Ur Rehman ◽  
Sabin Mihai ◽  
Andrei C. Popescu
Keyword(s):  
Mechanical Properties ◽  
Corrosion Resistance ◽  
Laser Shock Peening ◽  
Laser Shock ◽  
Post Processing ◽  
Laser Polishing ◽  
Shock Peening ◽  
Processing Techniques ◽  
Am Processes ◽  
Conventional Machining

Additive manufacturing (AM) processes can produce three-dimensional (3D) near-net-shape parts based on computer-aided design (CAD) models. Compared to traditional manufacturing processes, AM processes can generate parts with intricate geometries, operational flexibility and reduced manufacturing time, thus saving time and money. On the other hand, AM processes face complex issues, including poor surface finish, unwanted microstructure phases, defects, wear tracks, reduced corrosion resistance and reduced fatigue life. These problems prevent AM parts from real-time operational applications. Post-processing techniques, including laser shock peening, laser polishing, conventional machining methods and thermal processes, are usually applied to resolve these issues. These processes have proved their capability to enhance the surface characteristics and physical and mechanical properties. In this study, various post-processing techniques and their implementations have been compiled. The effect of post-processing techniques on additively manufactured parts has been discussed. It was found that laser shock peening (LSP) can cause severe strain rate generation, especially in thinner components. LSP can control the surface regularities and local grain refinement, thus elevating the hardness value. Laser polishing (LP) can reduce surface roughness up to 95% and increase hardness, collectively, compared to the as-built parts. Conventional machining processes enhance surface quality; however, their influence on hardness has not been proved yet. Thermal post-processing techniques are applied to eliminate porosity up to 99.99%, increase corrosion resistance, and finally, the mechanical properties’ elevation. For future perspectives, to prescribe a particular post-processing technique for specific defects, standardization is necessary. This study provides a detailed overview of the post-processing techniques applied to enhance the mechanical and physical properties of AM-ed parts. A particular method can be chosen based on one’s requirements.

Hydrogen Generation Facilitates Sintering Atmospheres

2021 ◽  
Author(s):  
David Wolff
Keyword(s):  
Heat Conduction ◽  
Hydrogen Storage ◽  
Thermal Processing ◽  
Hydrogen Generation ◽  
Energy Content ◽  
High Energy ◽  
Pure Hydrogen ◽  
Post Processing ◽  
Hydrogen Supply ◽  
Processing Techniques

Abstract For annealing, brazing or sintering, furnace atmospheres help ensure that metals thermal processors obtain the results they need. Hydrogen-containing atmospheres are used to protect surfaces from oxidation, and to ensure satisfactory thermal processing results. Hydrogen-containing atmospheres make thermal processing more forgiving because the hydrogen improves heat conduction and actively cleans heated surfaces – reducing oxides and destroying surface impurities. For powder based fabrication such as P/M, MIM or binder-jet metal AM, the use of a hydrogen-containing thermal processing atmosphere ensures the highest possible density of the sintered parts without necessitating the use of post-processing techniques. Users of pure hydrogen or hydrogen-containing gas blend atmospheres often struggle with hydrogen supply options. Hydrogen storage may create compliance problems due to its flammability and high energy content. Hydrogen generation enables hydrogen use without hydrogen storage issues. Deployment of hydrogen generation can ease the addition of thermal processing atmospheres to new and existing processing facilities.

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