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Ischemic Lesion Growth in Patients with a Persistent Target Mismatch After Large Vessel Occlusion. Clin Neuroradiol 2023; 33:41-48. [PMID: 35789284 PMCID: PMC10014761 DOI: 10.1007/s00062-022-01180-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 05/11/2022] [Indexed: 11/03/2022]
Abstract
BACKGROUND Failure to reperfuse a cerebral occlusion resulting in a persistent penumbral pattern has not been fully described. METHODS We retrospectively reviewed patients with anterior large vessel occlusion who did not receive reperfusion, and underwent repeated perfusion imaging, with baseline imaging < 6 h after onset and follow-up scans from 16-168 h. A persistent target mismatch (PTM) was defined as core volume of < 100 mL, mismatch ratio > 1.2, and mismatch volume > 10 mL on follow-up imaging. Patients were divided into PTM or non-PTM groups. Ischemic core and penumbral volumes were compared between baseline and follow-up imaging between the two groups, and collateral flow status assessed using CT perfusion collateral index. RESULTS A total of 25 patients (14 PTM and 11 non-PTM) were enrolled in the study. Median core volumes increased slightly in the PTM group, from 22 to 36 ml. There was a much greater increase in the non-PTM group, from 57 to 190 ml. Penumbral volumes were stable in the PTM group from a median of 79 ml at baseline to 88 ml at follow-up, whereas penumbra was reduced in the non-PTM group, from 120 to 0 ml. Collateral flow status was also better in the PTM group and the median collateral index was 33% compared with 44% in the non-PTM group (p = 0.043). CONCLUSION Multiple patients were identified with limited core growth and large penumbra (persistent target mismatch) > 16 h after stroke onset, likely due to more favorable collateral flow.
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Harvell-Smith S, Tung LD, Thanh NTK. Magnetic particle imaging: tracer development and the biomedical applications of a radiation-free, sensitive, and quantitative imaging modality. NANOSCALE 2022; 14:3658-3697. [PMID: 35080544 DOI: 10.1039/d1nr05670k] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Magnetic particle imaging (MPI) is an emerging tracer-based modality that enables real-time three-dimensional imaging of the non-linear magnetisation produced by superparamagnetic iron oxide nanoparticles (SPIONs), in the presence of an external oscillating magnetic field. As a technique, it produces highly sensitive radiation-free tomographic images with absolute quantitation. Coupled with a high contrast, as well as zero signal attenuation at-depth, there are essentially no limitations to where that can be imaged within the body. These characteristics enable various biomedical applications of clinical interest. In the opening sections of this review, the principles of image generation are introduced, along with a detailed comparison of the fundamental properties of this technique with other common imaging modalities. The main feature is a presentation on the up-to-date literature for the development of SPIONs tailored for improved imaging performance, and developments in the current and promising biomedical applications of this emerging technique, with a specific focus on theranostics, cell tracking and perfusion imaging. Finally, we will discuss recent progress in the clinical translation of MPI. As signal detection in MPI is almost entirely dependent on the properties of the SPION employed, this work emphasises the importance of tailoring the synthetic process to produce SPIONs demonstrating specific properties and how this impacts imaging in particular applications and MPI's overall performance.
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Affiliation(s)
- Stanley Harvell-Smith
- Biophysics Group, Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK.
- UCL Healthcare Biomagnetic and Nanomaterials Laboratories, University College London, 21 Albemarle Street, London W1S 4BS, UK
| | - Le Duc Tung
- Biophysics Group, Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK.
- UCL Healthcare Biomagnetic and Nanomaterials Laboratories, University College London, 21 Albemarle Street, London W1S 4BS, UK
| | - Nguyen Thi Kim Thanh
- Biophysics Group, Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK.
- UCL Healthcare Biomagnetic and Nanomaterials Laboratories, University College London, 21 Albemarle Street, London W1S 4BS, UK
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Foundations of Lesion Detection Using Machine Learning in Clinical Neuroimaging. ACTA NEUROCHIRURGICA. SUPPLEMENT 2021; 134:171-182. [PMID: 34862541 DOI: 10.1007/978-3-030-85292-4_21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
This chapter describes technical considerations and current and future clinical applications of lesion detection using machine learning in the clinical setting. Lesion detection is central to neuroradiology and precedes all further processes which include but are not limited to lesion characterization, quantification, longitudinal disease assessment, prognosis, and prediction of treatment response. A number of machine learning algorithms focusing on lesion detection have been developed or are currently under development which may either support or extend the imaging process. Examples include machine learning applications in stroke, aneurysms, multiple sclerosis, neuro-oncology, neurodegeneration, and epilepsy.
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Ludewig P, Graeser M, Forkert ND, Thieben F, Rández-Garbayo J, Rieckhoff J, Lessmann K, Förger F, Szwargulski P, Magnus T, Knopp T. Magnetic particle imaging for assessment of cerebral perfusion and ischemia. WILEY INTERDISCIPLINARY REVIEWS-NANOMEDICINE AND NANOBIOTECHNOLOGY 2021; 14:e1757. [PMID: 34617413 DOI: 10.1002/wnan.1757] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 08/30/2021] [Accepted: 09/03/2021] [Indexed: 02/04/2023]
Abstract
Stroke is one of the leading worldwide causes of death and sustained disability. Rapid and accurate assessment of cerebral perfusion is essential to diagnose and successfully treat stroke patients. Magnetic particle imaging (MPI) is a new technology with the potential to overcome some limitations of established imaging modalities. It is an innovative and radiation-free imaging technique with high sensitivity, specificity, and superior temporal resolution. MPI enables imaging and diagnosis of stroke and other neurological pathologies such as hemorrhage, tumors, and inflammatory processes. MPI scanners also offer the potential for targeted therapies of these diseases. Due to lower field requirements, MPI scanners can be designed as resistive magnets and employed as mobile devices for bedside imaging. With these advantages, MPI could accelerate and improve the diagnosis and treatment of neurological disorders. This review provides a basic introduction to MPI, discusses its current use for stroke imaging, and addresses future applications, including the potential for clinical implementation. This article is categorized under: Diagnostic Tools > In Vivo Nanodiagnostics and Imaging Therapeutic Approaches and Drug Discovery > Nanomedicine for Neurological Disease.
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Affiliation(s)
- Peter Ludewig
- Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Matthias Graeser
- Section for Biomedical Imaging at the University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Institute for Biomedical Imaging, Hamburg University of Technology, Hamburg, Germany.,Fraunhofer Research Institute for Individualized and Cell-based Medicine, Lübeck, Germany.,Institute for Medical Engineering, University of Lübeck, Lübeck, Germany
| | - Nils D Forkert
- Department of Radiology and Hotchkiss Brain Institute, University of Calgary, Calgary, Canada
| | - Florian Thieben
- Section for Biomedical Imaging at the University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Institute for Biomedical Imaging, Hamburg University of Technology, Hamburg, Germany
| | - Javier Rández-Garbayo
- Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Johanna Rieckhoff
- Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Katrin Lessmann
- Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Fynn Förger
- Section for Biomedical Imaging at the University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Institute for Biomedical Imaging, Hamburg University of Technology, Hamburg, Germany
| | - Patryk Szwargulski
- Section for Biomedical Imaging at the University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Institute for Biomedical Imaging, Hamburg University of Technology, Hamburg, Germany
| | - Tim Magnus
- Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Tobias Knopp
- Section for Biomedical Imaging at the University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Institute for Biomedical Imaging, Hamburg University of Technology, Hamburg, Germany
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5
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Affiliation(s)
- Kim Mouridsen
- Center of Functionally Integrative Neuroscience and MINDLab, Institute of Clinical Medicine, Aarhus University, Denmark (K.M.)
| | - Patrick Thurner
- Universitätsklinik für Radiologie und Nuklearmedizin, Vienna General Hospital, Austria (P.T.)
| | - Greg Zaharchuk
- Diagnostic Radiology, Stanford University School of Medicine, CA (G.Z.)
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Rava RA, Snyder KV, Mokin M, Waqas M, Allman AB, Senko JL, Podgorsak AR, Bhurwani MMS, Davies JM, Levy EI, Siddiqui AH, Ionita CN. Effect of computed tomography perfusion post-processing algorithms on optimal threshold selection for final infarct volume prediction. Neuroradiol J 2020; 33:273-285. [PMID: 32573337 DOI: 10.1177/1971400920934122] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
In acute ischemic stroke (AIS) patients, eligibility for endovascular intervention is commonly determined through computed tomography perfusion (CTP) analysis by quantifying ischemic tissue using perfusion parameter thresholds. However, thresholds are not uniform across all analysis methods due to dependencies on patient demographics and computational algorithms. This study aimed to investigate optimal perfusion thresholds for quantifying infarct and penumbra volumes using two post-processing CTP algorithms: Vitrea Bayesian and singular value decomposition plus (SVD+). We utilized 107 AIS patients (67 non-intervention patients and 40 successful reperfusion of thrombolysis in cerebral infarction (2b/3) patients). Infarct volumes were predicted for both post-processing algorithms through contralateral hemisphere comparisons using absolute time-to-peak (TTP) and relative regional cerebral blood volume (rCBV) thresholds ranging from +2.8 seconds to +9.3 seconds and -0.23 to -0.56 respectively. Optimal thresholds were determined by minimizing differences between predicted CTP and 24-hour fluid-attenuation inversion recovery magnetic resonance imaging infarct. Optimal thresholds were tested on 60 validation patients (30 intervention and 30 non-intervention) and compared using RAPID CTP software. Among the 67 non-intervention and 40 intervention patients, the following optimal thresholds were determined: intervention Bayesian: TTP = +4.8 seconds, rCBV = -0.29; intervention SVD+: TTP = +5.8 seconds, rCBV = -0.29; non-intervention Bayesian: TTP = +5.3 seconds, rCBV = -0.32; non-intervention SVD+: TTP = +6.3 seconds, rCBV = -0.26. When comparing SVD+ and Bayesian post-processing algorithms, optimal thresholds for TTP were significantly different for intervention and non-intervention patients. rCBV optimal thresholds were equal for intervention patients and significantly different for non-intervention patients. Comparison with commercially utilized software indicated similar performance.
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Affiliation(s)
- Ryan A Rava
- Department of Biomedical Engineering, University at Buffalo, USA.,Canon Stroke and Vascular Research Center, USA
| | - Kenneth V Snyder
- Canon Stroke and Vascular Research Center, USA.,Department of Neurosurgery, University at Buffalo, USA
| | - Maxim Mokin
- Department of Neurosurgery, University of South Florida, USA
| | - Muhammad Waqas
- Canon Stroke and Vascular Research Center, USA.,Department of Neurosurgery, University at Buffalo, USA
| | - Ariana B Allman
- Department of Biomedical Engineering, University at Buffalo, USA.,Canon Stroke and Vascular Research Center, USA
| | - Jillian L Senko
- Department of Biomedical Engineering, University at Buffalo, USA.,Canon Stroke and Vascular Research Center, USA
| | - Alexander R Podgorsak
- Department of Biomedical Engineering, University at Buffalo, USA.,Canon Stroke and Vascular Research Center, USA.,Department of Medical Physics, University at Buffalo, USA
| | | | - Jason M Davies
- Canon Stroke and Vascular Research Center, USA.,Department of Neurosurgery, University at Buffalo, USA.,Department of Bioinformatics, University at Buffalo, USA
| | - Elad I Levy
- Canon Stroke and Vascular Research Center, USA.,Department of Neurosurgery, University at Buffalo, USA
| | - Adnan H Siddiqui
- Canon Stroke and Vascular Research Center, USA.,Department of Neurosurgery, University at Buffalo, USA
| | - Ciprian N Ionita
- Department of Biomedical Engineering, University at Buffalo, USA.,Canon Stroke and Vascular Research Center, USA
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Magnetic Particle Imaging in Neurosurgery. World Neurosurg 2019; 125:261-270. [DOI: 10.1016/j.wneu.2019.01.180] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 01/16/2019] [Accepted: 01/19/2019] [Indexed: 01/19/2023]
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Gusev EI, Martynov MY, Yasamanova AN, Nikonov AA, Markin SS, Semenov AM. Thrombolytic therapy of ischemic stroke. Zh Nevrol Psikhiatr Im S S Korsakova 2018; 118:4-14. [DOI: 10.17116/jnevro20181181224] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Ludewig P, Gdaniec N, Sedlacik J, Forkert ND, Szwargulski P, Graeser M, Adam G, Kaul MG, Krishnan KM, Ferguson RM, Khandhar AP, Walczak P, Fiehler J, Thomalla G, Gerloff C, Knopp T, Magnus T. Magnetic Particle Imaging for Real-Time Perfusion Imaging in Acute Stroke. ACS NANO 2017; 11:10480-10488. [PMID: 28976180 DOI: 10.1021/acsnano.7b05784] [Citation(s) in RCA: 113] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The fast and accurate assessment of cerebral perfusion is fundamental for the diagnosis and successful treatment of stroke patients. Magnetic particle imaging (MPI) is a new radiation-free tomographic imaging method with a superior temporal resolution, compared to other conventional imaging methods. In addition, MPI scanners can be built as prehospital mobile devices, which require less complex infrastructure than computed tomography (CT) and magnetic resonance imaging (MRI). With these advantages, MPI could accelerate the stroke diagnosis and treatment, thereby improving outcomes. Our objective was to investigate the capabilities of MPI to detect perfusion deficits in a murine model of ischemic stroke. Cerebral ischemia was induced by inserting of a microfilament in the internal carotid artery in C57BL/6 mice, thereby blocking the blood flow into the medial cerebral artery. After the injection of a contrast agent (superparamagnetic iron oxide nanoparticles) specifically tailored for MPI, cerebral perfusion and vascular anatomy were assessed by the MPI scanner within seconds. To validate and compare our MPI data, we performed perfusion imaging with a small animal MRI scanner. MPI detected the perfusion deficits in the ischemic brain, which were comparable to those with MRI but in real-time. For the first time, we showed that MPI could be used as a diagnostic tool for relevant diseases in vivo, such as an ischemic stroke. Due to its shorter image acquisition times and increased temporal resolution compared to that of MRI or CT, we expect that MPI offers the potential to improve stroke imaging and treatment.
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Affiliation(s)
| | - Nadine Gdaniec
- Institute for Biomedical Imaging, Hamburg University of Technology , 21071 Hamburg, Germany
| | | | - Nils D Forkert
- Department of Radiology and Hotchkiss Brain Institute, University of Calgary , Calgary, AB T2N 1N4, Canada
| | - Patryk Szwargulski
- Institute for Biomedical Imaging, Hamburg University of Technology , 21071 Hamburg, Germany
| | - Matthias Graeser
- Institute for Biomedical Imaging, Hamburg University of Technology , 21071 Hamburg, Germany
| | | | | | - Kannan M Krishnan
- LodeSpin Laboratories LLC , Seattle, Washington 98103, United States
- Materials Science and Engineering Department, University of Washington , Seattle, Washington 98195, United States
| | | | - Amit P Khandhar
- LodeSpin Laboratories LLC , Seattle, Washington 98103, United States
| | - Piotr Walczak
- Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine , Baltimore, Maryland 21205, United States
- Department of Neurology and Neurosurgery, University of Warmia and Mazury , Olsztyn, Poland
| | | | | | | | - Tobias Knopp
- Institute for Biomedical Imaging, Hamburg University of Technology , 21071 Hamburg, Germany
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