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Chalet L, Boutelier T, Christen T, Raguenes D, Debatisse J, Eker OF, Becker G, Nighoghossian N, Cho TH, Canet-Soulas E, Mechtouff L. Clinical Imaging of the Penumbra in Ischemic Stroke: From the Concept to the Era of Mechanical Thrombectomy. Front Cardiovasc Med 2022; 9:861913. [PMID: 35355966 PMCID: PMC8959629 DOI: 10.3389/fcvm.2022.861913] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 02/11/2022] [Indexed: 01/01/2023] Open
Abstract
The ischemic penumbra is defined as the severely hypoperfused, functionally impaired, at-risk but not yet infarcted tissue that will be progressively recruited into the infarct core. Early reperfusion aims to save the ischemic penumbra by preventing infarct core expansion and is the mainstay of acute ischemic stroke therapy. Intravenous thrombolysis and mechanical thrombectomy for selected patients with large vessel occlusion has been shown to improve functional outcome. Given the varying speed of infarct core progression among individuals, a therapeutic window tailored to each patient has recently been proposed. Recent studies have demonstrated that reperfusion therapies are beneficial in patients with a persistent ischemic penumbra, beyond conventional time windows. As a result, mapping the penumbra has become crucial in emergency settings for guiding personalized therapy. The penumbra was first characterized as an area with a reduced cerebral blood flow, increased oxygen extraction fraction and preserved cerebral metabolic rate of oxygen using positron emission tomography (PET) with radiolabeled O2. Because this imaging method is not feasible in an acute clinical setting, the magnetic resonance imaging (MRI) mismatch between perfusion-weighted imaging and diffusion-weighted imaging, as well as computed tomography perfusion have been proposed as surrogate markers to identify the penumbra in acute ischemic stroke patients. Transversal studies comparing PET and MRI or using longitudinal assessment of a limited sample of patients have been used to define perfusion thresholds. However, in the era of mechanical thrombectomy, these thresholds are debatable. Using various MRI methods, the original penumbra definition has recently gained a significant interest. The aim of this review is to provide an overview of the evolution of the ischemic penumbra imaging methods, including their respective strengths and limitations, as well as to map the current intellectual structure of the field using bibliometric analysis and explore future directions.
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Affiliation(s)
- Lucie Chalet
- Univ Lyon, CarMeN Laboratory, INSERM, INRA, INSA Lyon, Université Claude Bernard Lyon 1, Lyon, France
- Olea Medical, La Ciotat, France
| | | | - Thomas Christen
- Grenoble Institut Neurosciences, INSERM, U1216, Univ. Grenoble Alpes, Grenoble, France
| | | | - Justine Debatisse
- Univ Lyon, CarMeN Laboratory, INSERM, INRA, INSA Lyon, Université Claude Bernard Lyon 1, Lyon, France
| | - Omer Faruk Eker
- CREATIS, CNRS UMR-5220, INSERM U1206, Université Lyon 1, Villeurbanne, France
- Neuroradiology Department, Hospices Civils of Lyon, Lyon, France
| | - Guillaume Becker
- Univ Lyon, CarMeN Laboratory, INSERM, INRA, INSA Lyon, Université Claude Bernard Lyon 1, Lyon, France
| | - Norbert Nighoghossian
- Univ Lyon, CarMeN Laboratory, INSERM, INRA, INSA Lyon, Université Claude Bernard Lyon 1, Lyon, France
- Stroke Department, Hospices Civils of Lyon, Lyon, France
| | - Tae-Hee Cho
- Univ Lyon, CarMeN Laboratory, INSERM, INRA, INSA Lyon, Université Claude Bernard Lyon 1, Lyon, France
- Stroke Department, Hospices Civils of Lyon, Lyon, France
| | - Emmanuelle Canet-Soulas
- Univ Lyon, CarMeN Laboratory, INSERM, INRA, INSA Lyon, Université Claude Bernard Lyon 1, Lyon, France
| | - Laura Mechtouff
- Univ Lyon, CarMeN Laboratory, INSERM, INRA, INSA Lyon, Université Claude Bernard Lyon 1, Lyon, France
- Stroke Department, Hospices Civils of Lyon, Lyon, France
- *Correspondence: Laura Mechtouff
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Katyal A, Bhaskar SMM. Value of pre-intervention CT perfusion imaging in acute ischemic stroke prognosis. DIAGNOSTIC AND INTERVENTIONAL RADIOLOGY (ANKARA, TURKEY) 2021; 27:774-785. [PMID: 34792033 DOI: 10.5152/dir.2021.20805] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Noninvasive imaging plays an important role in acute stroke towards diagnosis and ongoing management of patients. Systemic thrombolysis and endovascular thrombectomy (EVT) are proven treatments currently used in standards of care in acute stroke settings. The role of computed tomography angiography (CTA) in selecting patients with large vessel occlusion for EVT is well established. However, the value of CT perfusion (CTP) imaging in predicting outcomes after stroke remains ambiguous. This article critically evaluates the value of multimodal CT imaging in early diagnosis and prognosis of acute ischemic stroke with a focus on the role of CTP in delineating tissue characteristics, patient selection, and outcomes after reperfusion therapy. Insights on various technical and clinical considerations relevant to CTP applications in acute ischemic stroke, recommendations for existing workflow, and future areas of research are discussed.
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Affiliation(s)
- Anubhav Katyal
- Neurovascular Imaging Laboratory, Ingham Institute for Applied Medical Research, Clinical Sciences Stream, Sydney, Australia; University of New South Wales (UNSW), South Western Sydney Clinical School, NSW, Australia
| | - Sonu Menachem Maimonides Bhaskar
- Neurovascular Imaging Laboratory, Ingham Institute for Applied Medical Research, Clinical Sciences Stream, Sydney, Australia; Department of Neurology - Neurophysiology, Liverpool Hospital - South West Sydney Local Health District (SWSLHD), Sydney, Australia;University of New South Wales (UNSW), South Western Sydney Clinical School, NSW, Australia; Ingham Institute for Applied Medical Research, Stroke - Neurology Research Group, Sydney, Australia; NSW Brain Clot Bank, NSW Health Statewide Biobank and NSW Health Pathology, Sydney, NSW, Australia;Thrombolysis and Endovascular WorkFLOw Network (TEFLON), Sydney, Australia
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Bonney PA, Walcott BP, Singh P, Nguyen PL, Sanossian N, Mack WJ. The Continued Role and Value of Imaging for Acute Ischemic Stroke. Neurosurgery 2020; 85:S23-S30. [PMID: 31197337 DOI: 10.1093/neuros/nyz068] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Accepted: 02/26/2019] [Indexed: 11/12/2022] Open
Abstract
Advances in neuroimaging in the last 2 decades have revolutionized the management of acute ischemic stroke (AIS). Here we review the development of computed tomography (CT) and magnetic resonance imaging (MRI) modalities used to guide treatment of patients with AIS characterized by large vessel occlusion. In particular, we highlight recent randomized trials and their patient selection methodologies to detail the progression of these selection paradigms. With advanced imaging, distinction between at-risk penumbra and ischemic core in AIS may be performed using either CT or MRI. While limitations exist for methodologies to quantify core and penumbra, commercially available fully automated software packages provide useful information to guide treatment decisions. Randomized controlled trials implementing perfusion imaging to patient selection algorithms have demonstrated marked success in improving functional outcomes in patients with large vessel occlusions. As such, imaging has become a vital aspect of AIS treatment in selecting patients who may benefit from mechanical thrombectomy.
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Affiliation(s)
- Phillip A Bonney
- Department of Neurological Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Brian P Walcott
- Department of Neurological Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Parampreet Singh
- Department of Neurological Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Peggy L Nguyen
- Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Nerses Sanossian
- Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - William J Mack
- Department of Neurological Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California
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Hoelter P, Schmidt M, Breuer L, Kallmünzer B, Schwab S, Doerfler A, Engelhorn T. Endovascular treatment in patients with large vessel occlusion: reduced mortality despite minimal penumbra. Neuroradiology 2019; 61:1469-1476. [DOI: 10.1007/s00234-019-02280-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2019] [Accepted: 08/12/2019] [Indexed: 02/01/2023]
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Nannoni S, Cereda CW, Sirimarco G, Lambrou D, Strambo D, Eskandari A, Dunet V, Wintermark M, Michel P. Collaterals are a major determinant of the core but not the penumbra volume in acute ischemic stroke. Neuroradiology 2019; 61:971-978. [PMID: 31123760 DOI: 10.1007/s00234-019-02224-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 05/08/2019] [Indexed: 11/26/2022]
Abstract
PURPOSE Determinants of early loss of ischemic tissue (core) or its prolonged survival (penumbra) in acute ischemic stroke (AIS) are poorly understood. We aimed to identify radiological associations of core and penumbra volumes on CT perfusion (CTP) in a large cohort of AIS. METHODS In the ASTRAL registry (2003-2016), we identified consecutive AIS patients with proximal middle cerebral artery (MCA) occlusion. We calculated core and penumbra volumes using established thresholds and the mismatch ratio (MR). We graded collaterals into three categories on CT-angiography. We used clot burden score (CBS) to quantify the clot length. We related CTP volumes to radiological variables in multivariate regression analyses, adjusted for time from stroke onset to first imaging. RESULTS The median age of the 415 included patients was 69 years (IQR = 21) and 49% were female. Median admission NIHSS was 16 (11) and median delay to imaging 2.2 h (1.9). Lower core volumes were associated with higher ASPECTS (hazard ratio = 1.08), absence of hyperdense MCA sign (HR = 0.70), higher CBS (i.e., smaller clot, HR = 1.10), and better collaterals (HR = 1.95). Higher penumbra volumes were related to lower CBS (i.e., longer clot, HR = 1.08) and proximal intracranial occlusion (HR = 1.47), but not to collaterals. Higher MR was found in absence of hyperdense MCA sign (HR = 1.28), absence of distal intracranial occlusion (HR = 1.39), and with better collaterals (HR = 0.52). CONCLUSIONS In AIS, better collaterals were associated with lower core volumes, but not with higher penumbra volumes. This suggests a major role of collaterals in early tissue loss and their limited significance as marker of salvageable tissue.
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Affiliation(s)
- Stefania Nannoni
- Stroke Center, Neurology Service, Lausanne University Hospital, Rue du Bugnon, 46, 1011, Lausanne, Switzerland.
| | - Carlo W Cereda
- Stroke Center, Neurology Service, Lausanne University Hospital, Rue du Bugnon, 46, 1011, Lausanne, Switzerland
- Stroke Center, Neurology Service, Neurocenter of Southern Switzerland, Ospedale Civico di Lugano, Lugano, Switzerland
| | - Gaia Sirimarco
- Stroke Center, Neurology Service, Lausanne University Hospital, Rue du Bugnon, 46, 1011, Lausanne, Switzerland
| | - Dimitris Lambrou
- Stroke Center, Neurology Service, Lausanne University Hospital, Rue du Bugnon, 46, 1011, Lausanne, Switzerland
| | - Davide Strambo
- Stroke Center, Neurology Service, Lausanne University Hospital, Rue du Bugnon, 46, 1011, Lausanne, Switzerland
| | - Ashraf Eskandari
- Stroke Center, Neurology Service, Lausanne University Hospital, Rue du Bugnon, 46, 1011, Lausanne, Switzerland
| | - Vincent Dunet
- Department of Diagnostic and Interventional Radiology, Lausanne University Hospital, Lausanne, Switzerland
| | - Max Wintermark
- Department of Radiology, Neuroradiology Division, Stanford University and Medical Center, Stanford, USA
| | - Patrik Michel
- Stroke Center, Neurology Service, Lausanne University Hospital, Rue du Bugnon, 46, 1011, Lausanne, Switzerland
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Jiang B, Ball RL, Michel P, Li Y, Zhu G, Ding V, Su B, Naqvi Z, Eskandari A, Desai M, Wintermark M. Factors influencing infarct growth including collateral status assessed using computed tomography in acute stroke patients with large artery occlusion. Int J Stroke 2019; 14:603-612. [PMID: 31096871 DOI: 10.1177/1747493019851278] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
In major ischemic stroke caused by a large artery occlusion, neuronal loss varies considerably across individuals without revascularization. This study aims to identify which patient characteristics are most highly associated with this variability. Demographic and clinical information were retrospectively collected on a registry of 878 patients. Imaging biomarkers including Alberta Stroke Program Early CT score, noncontrast head computed tomography infarct volume, perfusion computed tomography infarct core and penumbra, occlusion site, collateral score, and recanalization status were evaluated on the baseline and early follow-up computed tomography images. Infarct growth rates were calculated by dividing infarct volumes by the time elapsed between the computed tomography scan and the symptom onset. Collateral score was graded into four levels (0, 1, 2, and 3) in comparison with the normal side. Correlation of perfusion computed tomography and noncontrast head computed tomography infarct volumes and infarct growth rates were estimated with the nonparametric Spearman's rank correlation. Conditional inference trees were used to identify the clinical and imaging biomarkers that were most highly associated with the infarct growth rate and modified Rankin Scale at 90 days. Two hundred and thirty-two patients met the inclusion criteria for this study. The median infarct growth rates for perfusion computed tomography and noncontrast head computed tomography were 11.2 and 6.2 ml/log(min) in logarithmic model, and 18.9 and 10.4 ml/h in linear model, respectively. Noncontrast head computed tomography and perfusion computed tomography infarct volumes and infarct growth rates were significantly correlated (rho=0.53; P < 0.001). Collateral status was the strongest predictor for infarct growth rates. For collateral=0, the perfusion computed tomography and noncontrast head computed tomography infarct growth rate were 31.56 and 16.86 ml/log(min), respectively. Patients who had collateral >0 and penumbra volumes>92 ml had the lowest predicted perfusion computed tomography infarct growth rates (6.61 ml/log(min)). Collateral status was closely related to the diversity of infarct growth rates, poor collaterals were associated with a faster infarct growth rates and vice versa.
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Affiliation(s)
- Bin Jiang
- 1 Department of Radiology, Neuroradiology Section, Stanford University School of Medicine, Stanford, USA
| | - Robyn L Ball
- 2 Department of Medicine, Quantitative Sciences Unit, Stanford University, Stanford, USA
| | - Patrik Michel
- 3 Department of Neurology, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland
| | - Ying Li
- 1 Department of Radiology, Neuroradiology Section, Stanford University School of Medicine, Stanford, USA
| | - Guangming Zhu
- 1 Department of Radiology, Neuroradiology Section, Stanford University School of Medicine, Stanford, USA
| | - Victoria Ding
- 2 Department of Medicine, Quantitative Sciences Unit, Stanford University, Stanford, USA
| | - Bochao Su
- 1 Department of Radiology, Neuroradiology Section, Stanford University School of Medicine, Stanford, USA
| | - Zack Naqvi
- 1 Department of Radiology, Neuroradiology Section, Stanford University School of Medicine, Stanford, USA
| | - Ashraf Eskandari
- 3 Department of Neurology, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland
| | - Manisha Desai
- 2 Department of Medicine, Quantitative Sciences Unit, Stanford University, Stanford, USA
| | - Max Wintermark
- 1 Department of Radiology, Neuroradiology Section, Stanford University School of Medicine, Stanford, USA
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Ginsberg MD. The cerebral collateral circulation: Relevance to pathophysiology and treatment of stroke. Neuropharmacology 2017; 134:280-292. [PMID: 28801174 DOI: 10.1016/j.neuropharm.2017.08.003] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 07/28/2017] [Accepted: 08/06/2017] [Indexed: 12/29/2022]
Abstract
The brain's collateral circulation consists of arterial anastomotic channels capable of providing nutrient perfusion to brain regions whose normal sources of flow have become compromised, as occurs in acute ischemic stroke. Modern CT-based neuroimaging is capable of providing detailed information as to collateral extent and sufficiency and is complemented by magnetic resonance-based methods. In the present era of standard-of-care IV thrombolysis for acute ischemic stroke, and following the recent therapeutic successes of randomized clinical trials of acute endovascular intervention, the sufficiency of the collateral circulation has been convincingly established as a key factor influencing the likelihood of successful reperfusion and favorable clinical outcome. This article reviews the features of the brain's collateral circulation; methods for its evaluation in the acute clinical setting; the relevance of collateral circulation to prognosis in acute ischemic stroke; the specific insights into the collateral circulation learned from recent trials of endovascular intervention; and the major influence of genetic factors. Finally, we emphasize the need to develop therapeutic approaches to augment collateral perfusion as an adjunctive strategy to be employed along with, or prior to, thrombolysis and endovascular interventions, and we highlight the possible potential of inhaled nitric oxide, albumin, and other approaches. This article is part of the Special Issue entitled 'Cerebral Ischemia'.
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Affiliation(s)
- Myron D Ginsberg
- Department of Neurology, University of Miami Miller School of Medicine, Clinical Research Center, Room 1331, 1120 NW 14th Street, Miami, FL 33136, USA.
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Endovascular Thrombectomy in Acute Ischemic Stroke: Outcome in Referred Versus Directly Admitted Patients. Clin Neuroradiol 2017; 28:235-244. [DOI: 10.1007/s00062-017-0558-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Accepted: 01/09/2017] [Indexed: 11/25/2022]
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