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Sun J, Werdiger F, Blair C, Chen C, Yang Q, Bivard A, Lin L, Parsons M. Automatic segmentation of hemorrhagic transformation on follow-up non-contrast CT after acute ischemic stroke. Front Neuroinform 2024; 18:1382630. [PMID: 38689832 PMCID: PMC11058994 DOI: 10.3389/fninf.2024.1382630] [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: 02/06/2024] [Accepted: 03/30/2024] [Indexed: 05/02/2024] Open
Abstract
Background Hemorrhagic transformation (HT) following reperfusion therapies is a serious complication for patients with acute ischemic stroke. Segmentation and quantification of hemorrhage provides critical insights into patients' condition and aids in prognosis. This study aims to automatically segment hemorrhagic regions on follow-up non-contrast head CT (NCCT) for stroke patients treated with endovascular thrombectomy (EVT). Methods Patient data were collected from 10 stroke centers across two countries. We propose a semi-automated approach with adaptive thresholding methods, eliminating the need for extensive training data and reducing computational demands. We used Dice Similarity Coefficient (DSC) and Lin's Concordance Correlation Coefficient (Lin's CCC) to evaluate the performance of the algorithm. Results A total of 51 patients were included, with 28 Type 2 hemorrhagic infarction (HI2) cases and 23 parenchymal hematoma (PH) cases. The algorithm achieved a mean DSC of 0.66 ± 0.17. Notably, performance was superior for PH cases (mean DSC of 0.73 ± 0.14) compared to HI2 cases (mean DSC of 0.61 ± 0.18). Lin's CCC was 0.88 (95% CI 0.79-0.93), indicating a strong agreement between the algorithm's results and the ground truth. In addition, the algorithm demonstrated excellent processing time, with an average of 2.7 s for each patient case. Conclusion To our knowledge, this is the first study to perform automated segmentation of post-treatment hemorrhage for acute stroke patients and evaluate the performance based on the radiological severity of HT. This rapid and effective tool has the potential to assist with predicting prognosis in stroke patients with HT after EVT.
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Affiliation(s)
- Jiacheng Sun
- Sydney Brain Centre, The Ingham Institute for Applied Medical Research, Liverpool, NSW, Australia
- South Western Sydney Clinical School, University of New South Wales, Sydney, NSW, Australia
| | - Freda Werdiger
- Melbourne Brain Centre at Royal Melbourne Hospital, Melbourne, VIC, Australia
- Department of Medicine, University of Melbourne, Melbourne, VIC, Australia
| | - Christopher Blair
- Sydney Brain Centre, The Ingham Institute for Applied Medical Research, Liverpool, NSW, Australia
- South Western Sydney Clinical School, University of New South Wales, Sydney, NSW, Australia
- Department of Neurology and Neurophysiology, Liverpool Hospital, Sydney, NSW, Australia
| | - Chushuang Chen
- South Western Sydney Clinical School, University of New South Wales, Sydney, NSW, Australia
| | - Qing Yang
- Apollo Medical Imaging Technology Pty. Ltd., Melbourne, VIC, Australia
| | - Andrew Bivard
- Melbourne Brain Centre at Royal Melbourne Hospital, Melbourne, VIC, Australia
- Department of Medicine, University of Melbourne, Melbourne, VIC, Australia
| | - Longting Lin
- Sydney Brain Centre, The Ingham Institute for Applied Medical Research, Liverpool, NSW, Australia
- South Western Sydney Clinical School, University of New South Wales, Sydney, NSW, Australia
| | - Mark Parsons
- Sydney Brain Centre, The Ingham Institute for Applied Medical Research, Liverpool, NSW, Australia
- South Western Sydney Clinical School, University of New South Wales, Sydney, NSW, Australia
- Department of Neurology and Neurophysiology, Liverpool Hospital, Sydney, NSW, Australia
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Werdiger F, Gotla S, Visser M, Kolacz J, Yogendrakumar V, Beharry J, Valente M, Sharobeam A, Parsons MW, Bivard A. Automated occlusion detection for the diagnosis of acute ischemic stroke: A detailed performance review. Eur J Radiol 2023; 164:110845. [PMID: 37148842 DOI: 10.1016/j.ejrad.2023.110845] [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: 10/28/2022] [Revised: 04/15/2023] [Accepted: 04/20/2023] [Indexed: 05/08/2023]
Abstract
INTRODUCTION Stroke is a leading cause of adult disability and death worldwide. Automated detection of stroke on brain imaging has promise in a time critical environment. We present a method for the automated detection of intracranial occlusions on dynamic CT Angiography (CTA) causing acute ischemic stroke. METHODS We derived dynamic CTA images from CT Perfusion (CTP) data and utilised advanced image processing to enhance and display major cerebral blood vessels for symmetry analysis. We reviewed the performance of the algorithm on a cohort of 207 patients from the International Stroke Perfusion Imaging Registry (INSPIRE), with Large Vessel Occlusion (LVO) and non-LVO strokes. Included in the data were images with chronic stroke, various artefacts, incomplete vessel occlusions, and images of poorer quality. All images were annotated by stroke experts. In addition, each image was graded in terms of the difficulty of the task of occlusion detection. Performance was evaluated on the overall cohort, and with respect to occlusion location, collateral grade, and task difficulty. We also evaluated the impact of including additional perfusion data. RESULTS Images with a rating of lower difficulty achieved a sensitivity and specificity of 96% and 90%, respectively, while images with a moderate difficulty rating achieved 88% and 50%, respectively. For cases of high difficulty, where more than two experts or additional data were required to reach consensus, sensitivity and specificity was 53% and 11%. The addition of perfusion data to the dCTA images increased the specificity by 38%. CONCLUSION We have provided an unbiased interpretation of algorithm performance. Further developments include generalising to conventional CTA and employing the algorithm in a clinical setting for prospective studies.
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Affiliation(s)
- Freda Werdiger
- Melbourne Brain Centre at Royal Melbourne Hospital, Melbourne, Australia; Department of Medicine, University of Melbourne, Melbourne, Australia.
| | - Sunay Gotla
- Southwestern Sydney Clinical School, University of New South Wales, Sydney, Australia
| | - Milanka Visser
- Melbourne Brain Centre at Royal Melbourne Hospital, Melbourne, Australia; Department of Medicine, University of Melbourne, Melbourne, Australia
| | - James Kolacz
- Melbourne Brain Centre at Royal Melbourne Hospital, Melbourne, Australia; Department of Medicine, University of Melbourne, Melbourne, Australia
| | - Vignan Yogendrakumar
- Melbourne Brain Centre at Royal Melbourne Hospital, Melbourne, Australia; Department of Medicine, University of Melbourne, Melbourne, Australia
| | - James Beharry
- Melbourne Brain Centre at Royal Melbourne Hospital, Melbourne, Australia
| | - Michael Valente
- Melbourne Brain Centre at Royal Melbourne Hospital, Melbourne, Australia; Department of Medicine, University of Melbourne, Melbourne, Australia
| | - Angelos Sharobeam
- Melbourne Brain Centre at Royal Melbourne Hospital, Melbourne, Australia; Department of Medicine, University of Melbourne, Melbourne, Australia
| | - Mark W Parsons
- Apollo Medical Imaging, Melbourne, Australia; Ingham Institute for Applied Medical Research, Liverpool, NSW, Australia; Department of Neurology, Liverpool Hospital, NSW, Australia
| | - Andrew Bivard
- Melbourne Brain Centre at Royal Melbourne Hospital, Melbourne, Australia; Department of Medicine, University of Melbourne, Melbourne, Australia
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Werdiger F, Visser M, Bivard A, Li X, Gotla S, Sharobeam A, Valente M, Beharry J, Yogendrakumar V, Parsons MW. Benchmark dataset for clot detection in ischemic stroke vessel-based imaging: CODEC-IV. Neuroimage 2023; 271:119985. [PMID: 36933627 DOI: 10.1016/j.neuroimage.2023.119985] [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: 07/31/2021] [Revised: 01/18/2023] [Accepted: 02/24/2023] [Indexed: 03/18/2023] Open
Abstract
We present an annotated dataset for the purposes of creating a benchmark in Artificial Intelligence for automated clot detection. While there are commercial tools available for automated clot detection on computed tomographic (CT) angiographs, they have not been compared in a standardized manner whereby accuracy is reported on a publicly available benchmark dataset. Furthermore, there are known difficulties in automated clot detection - namely, cases where there is robust collateral flow, or residual flow and occlusions of the smaller vessels - and it is necessary to drive an initiative to overcome these challenges. Our dataset contains 159 multiphase CTA patient datasets, derived from CTP and annotated by expert stroke neurologists. In addition to images where the clot is marked, the expert neurologists have provided information about clot location, hemisphere and the degree of collateral flow. The data is available on request by researchers via an online form, and we will host a leaderboard where the results of clot detection algorithms on the dataset will be displayed. Participants are invited to submit an algorithm to us for evaluation using the evaluation tool, which is made available at together with the form at https://github.com/MBC-Neuroimaging/ClotDetectEval.
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Affiliation(s)
- Freda Werdiger
- Melbourne Brain Centre at Royal Melbourne Hospital, Melbourne, Australia; Department of Medicine, University of Melbourne, Melbourne, Australia.
| | - Milanka Visser
- Melbourne Brain Centre at Royal Melbourne Hospital, Melbourne, Australia; Department of Medicine, University of Melbourne, Melbourne, Australia
| | - Andrew Bivard
- Melbourne Brain Centre at Royal Melbourne Hospital, Melbourne, Australia; Department of Medicine, University of Melbourne, Melbourne, Australia
| | - Xingjuan Li
- Southwestern Sydney Clinical School, University of New South Wales, Sydney, Australia; Ingham Institute for Applied Medical Research, Liverpool, NSW, Australia
| | - Sunay Gotla
- Apollo Medical Imaging, Melbourne, Australia
| | - Angelos Sharobeam
- Melbourne Brain Centre at Royal Melbourne Hospital, Melbourne, Australia; Department of Medicine, University of Melbourne, Melbourne, Australia
| | - Michael Valente
- Melbourne Brain Centre at Royal Melbourne Hospital, Melbourne, Australia; Department of Medicine, University of Melbourne, Melbourne, Australia
| | - James Beharry
- Melbourne Brain Centre at Royal Melbourne Hospital, Melbourne, Australia
| | - Vignan Yogendrakumar
- Melbourne Brain Centre at Royal Melbourne Hospital, Melbourne, Australia; Department of Medicine, University of Melbourne, Melbourne, Australia
| | - Mark W Parsons
- Southwestern Sydney Clinical School, University of New South Wales, Sydney, Australia; Ingham Institute for Applied Medical Research, Liverpool, NSW, Australia; Department of Neurology, Liverpool Hospital, NSW, Australia
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Sun J, Lam C, Christie L, Blair C, Li X, Werdiger F, Yang Q, Bivard A, Lin L, Parsons M. Risk factors of hemorrhagic transformation in acute ischaemic stroke: A systematic review and meta-analysis. Front Neurol 2023; 14:1079205. [PMID: 36891475 PMCID: PMC9986457 DOI: 10.3389/fneur.2023.1079205] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [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: 10/25/2022] [Accepted: 01/31/2023] [Indexed: 02/22/2023] Open
Abstract
Background Hemorrhagic transformation (HT) following reperfusion therapies for acute ischaemic stroke often predicts a poor prognosis. This systematic review and meta-analysis aims to identify risk factors for HT, and how these vary with hyperacute treatment [intravenous thrombolysis (IVT) and endovascular thrombectomy (EVT)]. Methods Electronic databases PubMed and EMBASE were used to search relevant studies. Pooled odds ratio (OR) with 95% confidence interval (CI) were estimated. Results A total of 120 studies were included. Atrial fibrillation and NIHSS score were common predictors for any intracerebral hemorrhage (ICH) after reperfusion therapies (both IVT and EVT), while a hyperdense artery sign (OR = 2.605, 95% CI 1.212-5.599, I 2 = 0.0%) and number of thrombectomy passes (OR = 1.151, 95% CI 1.041-1.272, I 2 = 54.3%) were predictors of any ICH after IVT and EVT, respectively. Common predictors for symptomatic ICH (sICH) after reperfusion therapies were age and serum glucose level. Atrial fibrillation (OR = 3.867, 95% CI 1.970-7.591, I 2 = 29.1%), NIHSS score (OR = 1.082, 95% CI 1.060-1.105, I 2 = 54.5%) and onset-to-treatment time (OR = 1.003, 95% CI 1.001-1.005, I 2 = 0.0%) were predictors of sICH after IVT. Alberta Stroke Program Early CT score (ASPECTS) (OR = 0.686, 95% CI 0.565-0.833, I 2 =77.6%) and number of thrombectomy passes (OR = 1.374, 95% CI 1.012-1.866, I 2 = 86.4%) were predictors of sICH after EVT. Conclusion Several predictors of ICH were identified, which varied by treatment type. Studies based on larger and multi-center data sets should be prioritized to confirm the results. Systematic review registration https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=268927, identifier: CRD42021268927.
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Affiliation(s)
- Jiacheng Sun
- Sydney Brain Centre, The Ingham Institute for Applied Medical Research, Liverpool, NSW, Australia.,South Western Sydney Clinical School, University of New South Wales, Sydney, NSW, Australia
| | - Christina Lam
- Melbourne Brain Centre at Royal Melbourne Hospital, Melbourne, VIC, Australia.,Department of Medicine, University of Melbourne, Melbourne, VIC, Australia
| | - Lauren Christie
- Sydney Brain Centre, The Ingham Institute for Applied Medical Research, Liverpool, NSW, Australia.,Allied Health Research Unit, St Vincent's Health Network Sydney, Sydney, NSW, Australia.,Faculty of Health Sciences, Australian Catholic University, North Sydney, NSW, Australia
| | - Christopher Blair
- Sydney Brain Centre, The Ingham Institute for Applied Medical Research, Liverpool, NSW, Australia.,South Western Sydney Clinical School, University of New South Wales, Sydney, NSW, Australia.,Department of Neurology and Neurophysiology, Liverpool Hospital, Sydney, NSW, Australia
| | - Xingjuan Li
- Queensland Department of Agriculture and Fisheries, Brisbane, QLD, Australia
| | - Freda Werdiger
- Melbourne Brain Centre at Royal Melbourne Hospital, Melbourne, VIC, Australia.,Department of Medicine, University of Melbourne, Melbourne, VIC, Australia
| | - Qing Yang
- Apollo Medical Imaging Technology Pty Ltd., Melbourne, VIC, Australia
| | - Andrew Bivard
- Melbourne Brain Centre at Royal Melbourne Hospital, Melbourne, VIC, Australia.,Department of Medicine, University of Melbourne, Melbourne, VIC, Australia
| | - Longting Lin
- Sydney Brain Centre, The Ingham Institute for Applied Medical Research, Liverpool, NSW, Australia.,South Western Sydney Clinical School, University of New South Wales, Sydney, NSW, Australia
| | - Mark Parsons
- Sydney Brain Centre, The Ingham Institute for Applied Medical Research, Liverpool, NSW, Australia.,South Western Sydney Clinical School, University of New South Wales, Sydney, NSW, Australia.,Department of Neurology and Neurophysiology, Liverpool Hospital, Sydney, NSW, Australia
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Werdiger F, Parsons MW, Visser M, Levi C, Spratt N, Kleinig T, Lin L, Bivard A. Machine learning segmentation of core and penumbra from acute stroke CT perfusion data. Front Neurol 2023; 14:1098562. [PMID: 36908587 PMCID: PMC9995438 DOI: 10.3389/fneur.2023.1098562] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [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: 11/20/2022] [Accepted: 02/02/2023] [Indexed: 02/25/2023] Open
Abstract
Introduction Computed tomography perfusion (CTP) imaging is widely used in cases of suspected acute ischemic stroke to positively identify ischemia and assess suitability for treatment through identification of reversible and irreversible tissue injury. Traditionally, this has been done via setting single perfusion thresholds on two or four CTP parameter maps. We present an alternative model for the estimation of tissue fate using multiple perfusion measures simultaneously. Methods We used machine learning (ML) models based on four different algorithms, combining four CTP measures (cerebral blood flow, cerebral blood volume, mean transit time and delay time) plus 3D-neighborhood (patch) analysis to predict the acute ischemic core and perfusion lesion volumes. The model was developed using 86 patient images, and then tested further on 22 images. Results XGBoost was the highest-performing algorithm. With standard threshold-based core and penumbra measures as the reference, the model demonstrated moderate agreement in segmenting core and penumbra on test images. Dice similarity coefficients for core and penumbra were 0.38 ± 0.26 and 0.50 ± 0.21, respectively, demonstrating moderate agreement. Skull-related image artefacts contributed to lower accuracy. Discussion Further development may enable us to move beyond the current overly simplistic core and penumbra definitions using single thresholds where a single error or artefact may lead to substantial error.
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Affiliation(s)
- Freda Werdiger
- Melbourne Brain Centre, Department of Neurology, The Royal Melbourne Hospital, Melbourne, VIC, Australia.,Department of Medicine, University of Melbourne, Melbourne, VIC, Australia
| | - Mark W Parsons
- Southwestern Sydney Clinical School, University of New South Wales, Sydney, NSW, Australia.,Department of Neurology, Liverpool Hospital, Liverpool, NSW, Australia.,Ingham Institute for Applied Medical Research, Liverpool, NSW, Australia
| | - Milanka Visser
- Melbourne Brain Centre, Department of Neurology, The Royal Melbourne Hospital, Melbourne, VIC, Australia.,Department of Medicine, University of Melbourne, Melbourne, VIC, Australia
| | - Christopher Levi
- Hunter Medical Research Institution, University of Newcastle, Newcastle, NSW, Australia.,Department of Neurology, John Hunter Hospital, University of Newcastle, Newcastle, NSW, Australia
| | - Neil Spratt
- Hunter Medical Research Institution, University of Newcastle, Newcastle, NSW, Australia.,Department of Neurology, John Hunter Hospital, University of Newcastle, Newcastle, NSW, Australia
| | - Tim Kleinig
- Department of Neurology, Royal Adelaide Hospital, Adelaide, SA, Australia
| | - Longting Lin
- Hunter Medical Research Institution, University of Newcastle, Newcastle, NSW, Australia.,Department of Neurology, John Hunter Hospital, University of Newcastle, Newcastle, NSW, Australia
| | - Andrew Bivard
- Melbourne Brain Centre, Department of Neurology, The Royal Melbourne Hospital, Melbourne, VIC, Australia.,Department of Medicine, University of Melbourne, Melbourne, VIC, Australia
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Werdiger F, Bivard A, Parsons M. Artificial Intelligence in Acute Ischemic Stroke. Artif Intell Med 2022. [DOI: 10.1007/978-3-030-64573-1_287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Habiel DM, Hohmann MS, Espindola MS, Coelho AL, Jones I, Jones H, Carnibella R, Pinar I, Werdiger F, Hogaboam CM. DNA-PKcs modulates progenitor cell proliferation and fibroblast senescence in idiopathic pulmonary fibrosis. BMC Pulm Med 2019; 19:165. [PMID: 31464599 PMCID: PMC6716822 DOI: 10.1186/s12890-019-0922-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [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: 11/29/2018] [Accepted: 08/19/2019] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Recent studies have highlighted the contribution of senescent mesenchymal and epithelial cells in Idiopathic Pulmonary Fibrosis (IPF), but little is known regarding the molecular mechanisms that regulate the accumulation of senescent cells in this disease. Therefore, we addressed the hypothesis that the loss of DNA repair mechanisms mediated by DNA protein kinase catalytic subunit (DNA-PKcs) in IPF, promoted the accumulation of mesenchymal progenitors and progeny, and the expression of senescent markers by these cell types. METHODS Surgical lung biopsy samples and lung fibroblasts were obtained from patients exhibiting slowly, rapidly or unknown progressing IPF and lung samples lacking any evidence of fibrotic disease (i.e. normal; NL). The expression of DNA-Pkcs in lung tissue was assessed by quantitative immunohistochemical analysis. Chronic inhibition of DNA-PKcs kinase activity was mimicked using a highly specific small molecule inhibitor, Nu7441. Proteins involved in DNA repair (stage-specific embryonic antigen (SSEA)-4+ cells) were determined by quantitative Ingenuity Pathway Analysis of transcriptomic datasets (GSE103488). Lastly, the loss of DNA-PKc was modeled in a humanized model of pulmonary fibrosis in NSG SCID mice genetically deficient in PRKDC (the transcript for DNA-PKcs) and treated with Nu7441. RESULTS DNA-PKcs expression was significantly reduced in IPF lung tissues. Chronic inhibition of DNA-PKcs by Nu7441 promoted the proliferation of SSEA4+ mesenchymal progenitor cells and a significant increase in the expression of senescence-associated markers in cultured lung fibroblasts. Importantly, mesenchymal progenitor cells and their fibroblast progeny derived from IPF patients showed a loss of transcripts encoding for DNA damage response and DNA repair components. Further, there was a significant reduction in transcripts encoding for PRKDC (the transcript for DNA-PKcs) in SSEA4+ mesenchymal progenitor cells from IPF patients compared with normal lung donors. In SCID mice lacking DNA-PKcs activity receiving IPF lung explant cells, treatment with Nu7441 promoted the expansion of progenitor cells, which was observed as a mass of SSEA4+ CgA+ expressing cells. CONCLUSIONS Together, our results show that the loss of DNA-PKcs promotes the expansion of SSEA4+ mesenchymal progenitors, and the senescence of their mesenchymal progeny.
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Affiliation(s)
- David M Habiel
- Department of Medicine, Cedars-Sinai Medical Center, Women's Guild Lung Institute, 127 S San Vicente Blvd., AHSP A9315, Los Angeles, CA, 90048, USA
| | - Miriam S Hohmann
- Department of Medicine, Cedars-Sinai Medical Center, Women's Guild Lung Institute, 127 S San Vicente Blvd., AHSP A9315, Los Angeles, CA, 90048, USA.
| | - Milena S Espindola
- Department of Medicine, Cedars-Sinai Medical Center, Women's Guild Lung Institute, 127 S San Vicente Blvd., AHSP A9315, Los Angeles, CA, 90048, USA
| | - Ana Lucia Coelho
- Department of Medicine, Cedars-Sinai Medical Center, Women's Guild Lung Institute, 127 S San Vicente Blvd., AHSP A9315, Los Angeles, CA, 90048, USA
| | - Isabelle Jones
- Department of Medicine, Cedars-Sinai Medical Center, Women's Guild Lung Institute, 127 S San Vicente Blvd., AHSP A9315, Los Angeles, CA, 90048, USA
| | - Heather Jones
- Department of Medicine, Cedars-Sinai Medical Center, Women's Guild Lung Institute, 127 S San Vicente Blvd., AHSP A9315, Los Angeles, CA, 90048, USA
| | - Richard Carnibella
- Laboratory of Dynamic Imaging, Mechanical and Aerospace Engineering, Monash University, Clayton, VIC, 3800, Australia
| | - Isaac Pinar
- Laboratory of Dynamic Imaging, Mechanical and Aerospace Engineering, Monash University, Clayton, VIC, 3800, Australia
| | - Freda Werdiger
- Laboratory of Dynamic Imaging, Mechanical and Aerospace Engineering, Monash University, Clayton, VIC, 3800, Australia
| | - Cory M Hogaboam
- Department of Medicine, Cedars-Sinai Medical Center, Women's Guild Lung Institute, 127 S San Vicente Blvd., AHSP A9315, Los Angeles, CA, 90048, USA.
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Preissner M, Murrie RP, Pinar I, Werdiger F, Carnibella RP, Zosky GR, Fouras A, Dubsky S. High resolution propagation-based imaging system for in vivo dynamic computed tomography of lungs in small animals. ACTA ACUST UNITED AC 2018; 63:08NT03. [DOI: 10.1088/1361-6560/aab8d2] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Werdiger F, Kitchen MJ, Paganin DM. Generalised Cornu spirals: an experimental study using hard x-rays. Opt Express 2016; 24:10620-10634. [PMID: 27409884 DOI: 10.1364/oe.24.010620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The Cornu spiral is a graphical aid that has been used historically to evaluate Fresnel integrals. It is also the Argand-plane mapping of a monochromatic complex scalar plane wave diffracted by a hard edge. We have successfully reconstructed a Cornu spiral due to diffraction of hard x-rays from a piece of Kapton tape. Additionally, we have explored the generalisation of the Cornu spiral by observing the Argand-plane mapping of complex scalar electromagnetic fields diffracted by a cylinder and a sphere embedded within a cylinder.
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