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Cho J, Zhang J, Spincemaille P, Zhang H, Nguyen TD, Zhang S, Gupta A, Wang Y. Multi-Echo Complex Quantitative Susceptibility Mapping and Quantitative Blood Oxygen Level-Dependent Magnitude (mcQSM + qBOLD or mcQQ) for Oxygen Extraction Fraction (OEF) Mapping. Bioengineering (Basel) 2024; 11:131. [PMID: 38391617 PMCID: PMC10886243 DOI: 10.3390/bioengineering11020131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 01/25/2024] [Accepted: 01/26/2024] [Indexed: 02/24/2024] Open
Abstract
Oxygen extraction fraction (OEF), the fraction of oxygen that tissue extracts from blood, is an essential biomarker used to directly assess tissue viability and function in neurologic disorders. In ischemic stroke, for example, increased OEF can indicate the presence of penumbra-tissue with low perfusion yet intact cellular integrity-making it a primary therapeutic target. However, practical OEF mapping methods are not currently available in clinical settings, owing to the impractical data acquisitions in positron emission tomography (PET) and the limitations of existing MRI techniques. Recently, a novel MRI-based OEF mapping technique, termed QQ, was proposed. It shows high potential for clinical use by utilizing a routine sequence and removing the need for impractical multiple gas inhalations. However, QQ relies on the assumptions of Gaussian noise in susceptibility and multi-echo gradient echo (mGRE) magnitude signals for OEF estimation. This assumption is unreliable in low signal-to-noise ratio (SNR) regions like disease-related lesions, risking inaccurate OEF estimation and potentially impacting clinical decisions. Addressing this, our study presents a novel multi-echo complex QQ (mcQQ) that models realistic Gaussian noise in mGRE complex signals. We implemented mcQQ using a deep learning framework (mcQQ-NET) and compared it with the existing QQ-NET in simulations, ischemic stroke patients, and healthy subjects, using identical training and testing datasets and schemes. In simulations, mcQQ-NET provided more accurate OEF than QQ-NET. In the subacute stroke patients, mcQQ-NET showed a lower average OEF ratio in lesions relative to unaffected contralateral normal tissue than QQ-NET. In the healthy subjects, mcQQ-NET provided uniform OEF maps, similar to QQ-NET, but without unrealistically high OEF outliers in areas of low SNR, such as SNR ≤ 15 (dB). Therefore, mcQQ-NET improves OEF accuracy by more accurately reflecting realistic Gaussian noise in complex mGRE signals. Its enhanced sensitivity to OEF abnormalities, based on more realistic biophysics modeling, suggests that mcQQ-NET has potential for investigating tissue variability in neurologic disorders.
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Affiliation(s)
- Junghun Cho
- Department of Biomedical Engineering, State University of New York at Buffalo, Buffalo, NY 14228, USA
| | - Jinwei Zhang
- Department of Radiology, Weill Cornell Medicine, New York, NY 10065, USA
| | | | - Hang Zhang
- Department of Radiology, Weill Cornell Medicine, New York, NY 10065, USA
| | - Thanh D Nguyen
- Department of Radiology, Weill Cornell Medicine, New York, NY 10065, USA
| | - Shun Zhang
- Department of Radiology, Weill Cornell Medicine, New York, NY 10065, USA
| | - Ajay Gupta
- Department of Radiology, Weill Cornell Medicine, New York, NY 10065, USA
| | - Yi Wang
- Department of Radiology, Weill Cornell Medicine, New York, NY 10065, USA
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Kawano H, Hirano T. Minimal Imaging Requirements. JOURNAL OF NEUROENDOVASCULAR THERAPY 2023; 17:243-256. [PMID: 38025254 PMCID: PMC10657732 DOI: 10.5797/jnet.ra.2023-0045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 08/09/2023] [Indexed: 12/01/2023]
Abstract
The minimal requirements for imaging studies prior to endovascular treatment (EVT) of acute ischemic stroke are those that can provide the information necessary to determine the indication for treatment (treatment triage) and procedural strategies without being time-consuming. An important notion is to determine whether the patient can benefit from EVT. We should recognize that the perfect diagnostic imaging technique does not yet exist, and each has advantages and disadvantages. Generally, stroke imaging protocols to triage for EVT include the following three options: 1) non-contrast CT and CTA, 2) CT perfusion and CTA, and 3) MRI and MRA. It is not known if perfusion imaging or MRI is mandatory for patients with stroke presenting within 6 hours of onset, although non-contrast CT alone has less power to obtain the necessary information. Dual-energy CT can distinguish between post-EVT hemorrhage and contrast agent leakage immediately after EVT.
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Affiliation(s)
- Hiroyuki Kawano
- Department of Stroke and Cerebrovascular Medicine, Kyorin University, Mitaka, Tokyo, Japan
| | - Teruyuki Hirano
- Department of Stroke and Cerebrovascular Medicine, Kyorin University, Mitaka, Tokyo, Japan
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Cao F, Wang M, Fan S, Han S, Guo Y, Zaman A, Guo J, Luo Y, Kang Y. Cerebral Venous Oxygen Saturation in Hypoperfusion Regions May Become a New Imaging Indicator to Predict the Clinical Outcome of Stroke. Life (Basel) 2022; 12:life12091312. [PMID: 36143349 PMCID: PMC9504954 DOI: 10.3390/life12091312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 08/20/2022] [Accepted: 08/23/2022] [Indexed: 11/16/2022] Open
Abstract
To automatically and quantitatively evaluate the venous oxygen saturation (SvO2) in cerebral ischemic tissues and explore its value in predicting prognosis. A retrospective study was conducted on 48 AIS patients hospitalized in our hospital from 2015−2018. Based on quantitative susceptibility mapping and perfusion-weighted imaging, this paper measured the cerebral SvO2 in hypoperfusion tissues and its change after intraarterial rt-PA treatment. The cerebral SvO2 in different hypoperfusion regions between the favorable and unfavorable clinical outcome groups was analyzed using an independent t-test. Relationships between cerebral SvO2 and clinical scores were determined using the Pearson correlation coefficient. The receiver operating characteristic process was conducted to evaluate the accuracy of cerebral SvO2 in predicting unfavorable clinical outcomes. Cerebral SvO2 in hypoperfusion (Tmax > 4 and 6 s) was significantly different between the two groups at follow-up (p < 0.05). Cerebral SvO2 and its changes before and after treatment were negatively correlated with clinical scores. The positive predictive value, negative predictive value, accuracy, and area under the curve of the cerebral SvO2 were higher than those predicted by the ischemic core. Therefore, the cerebral SvO2 of hypoperfusion regions was a stronger imaging predictor of unfavorable clinical outcomes after stroke.
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Affiliation(s)
- Fengqiu Cao
- College of Medicine and Biological Information Engineering, Northeastern University, Shenyang 110169, China
- College of Health Science and Environmental Engineering, Shenzhen Technology University, Shenzhen 518118, China
| | - Mingming Wang
- Department of Radiology, Shanghai Fourth People’s Hospital Affiliated to Tongji University School of Medicine, Shanghai 200434, China
| | - Shengyu Fan
- College of Medicine and Biological Information Engineering, Northeastern University, Shenyang 110169, China
| | - Shanhua Han
- Department of Radiology, Shanghai Fourth People’s Hospital Affiliated to Tongji University School of Medicine, Shanghai 200434, China
| | - Yingwei Guo
- College of Medicine and Biological Information Engineering, Northeastern University, Shenyang 110169, China
- College of Health Science and Environmental Engineering, Shenzhen Technology University, Shenzhen 518118, China
| | - Asim Zaman
- College of Health Science and Environmental Engineering, Shenzhen Technology University, Shenzhen 518118, China
- Engineering Research Centre of Medical Imaging and Intelligent Analysis, Ministry of Education, Shenyang 110169, China
| | - Jia Guo
- Department of Psychiatry, Columbia University, New York, NY 10027, USA
- Correspondence: (J.G.); (Y.L.); (Y.K.); Tel.: +86-139-4047-2926 (Y.K.)
| | - Yu Luo
- Department of Radiology, Shanghai Fourth People’s Hospital Affiliated to Tongji University School of Medicine, Shanghai 200434, China
- Correspondence: (J.G.); (Y.L.); (Y.K.); Tel.: +86-139-4047-2926 (Y.K.)
| | - Yan Kang
- College of Medicine and Biological Information Engineering, Northeastern University, Shenyang 110169, China
- College of Health Science and Environmental Engineering, Shenzhen Technology University, Shenzhen 518118, China
- Engineering Research Centre of Medical Imaging and Intelligent Analysis, Ministry of Education, Shenyang 110169, China
- School of Applied Technology, Shenzhen University, Shenzhen 518060, China
- Correspondence: (J.G.); (Y.L.); (Y.K.); Tel.: +86-139-4047-2926 (Y.K.)
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Wu PH, Rodríguez-Soto AE, Wiemken A, Englund EK, Rodgers ZB, Langham MC, Schwab RJ, Detre JA, Guo W, Wehrli FW. MRI evaluation of cerebral metabolic rate of oxygen (CMRO 2) in obstructive sleep apnea. J Cereb Blood Flow Metab 2022; 42:1049-1060. [PMID: 34994242 PMCID: PMC9125486 DOI: 10.1177/0271678x211071018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2021] [Revised: 11/15/2021] [Accepted: 12/10/2021] [Indexed: 01/09/2023]
Abstract
Patients with obstructive sleep apnea (OSA) are at elevated risk of developing systemic vascular disease and cognitive dysfunction. Here, cerebral oxygen metabolism was assessed in patients with OSA by means of a magnetic resonance-based method involving simultaneous measurements of cerebral blood flow rate and venous oxygen saturation in the superior sagittal sinus for a period of 10 minutes at an effective temporal resolution of 1.3 seconds before, during, and after repeated 24-second breath-holds mimicking spontaneous apneas, yielding, along with pulse oximetry-derived arterial saturation, whole-brain CMRO2 via Fick's Principle. Enrolled subjects were classified based on their apnea-hypopnea indices into OSA (N = 31) and non-sleep apnea reference subjects (NSA = 21), and further compared with young healthy subjects (YH, N = 10). OSA and NSA subjects were matched for age and body mass index. CMRO2 was lower in OSA than in the YH group during normal breathing (105.6 ± 14.1 versus 123.7 ± 22.8 μmol O2/min/100g, P = 0.01). Further, the fractional change in CMRO2 in response to a breath-hold challenge was larger in OSA than in the YH group (15.2 ± 9.2 versus 8.5 ± 3.4%, P = 0.04). However, there was no significant difference in CMRO2 between OSA and NSA subjects. The data suggest altered brain oxygen metabolism in OSA and possibly in NSA as well.
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Affiliation(s)
- Pei-Hsin Wu
- Department of Radiology, University of Pennsylvania, University of Pennsylvania, Philadelphia, PA, USA
- Department of Electrical Engineering, National Sun Yat-sen University, National Sun Yat-sen University, Kaohsiung, Taiwan
| | - Ana E Rodríguez-Soto
- Department of Radiology, University of Pennsylvania, University of Pennsylvania, Philadelphia, PA, USA
| | - Andrew Wiemken
- Division of Sleep Medicine, Department of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Erin K Englund
- Department of Radiology, University of Pennsylvania, University of Pennsylvania, Philadelphia, PA, USA
| | - Zachary B Rodgers
- Department of Radiology, University of Pennsylvania, University of Pennsylvania, Philadelphia, PA, USA
| | - Michael C Langham
- Department of Radiology, University of Pennsylvania, University of Pennsylvania, Philadelphia, PA, USA
| | - Richard J Schwab
- Division of Sleep Medicine, Department of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - John A Detre
- Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA
| | - Wensheng Guo
- Department of Epidemiology and Biostatistics, University of Pennsylvania, Philadelphia, PA, USA
| | - Felix W Wehrli
- Department of Radiology, University of Pennsylvania, University of Pennsylvania, Philadelphia, PA, USA
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5
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Fan H, Su P, Lin DDM, Goldberg EB, Walker A, Leigh R, Hillis AE, Lu H. Simultaneous Hemodynamic and Structural Imaging of Ischemic Stroke With Magnetic Resonance Fingerprinting Arterial Spin Labeling. Stroke 2022; 53:2016-2025. [PMID: 35291820 DOI: 10.1161/strokeaha.121.037066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Perfusion and structural imaging play an important role in ischemic stroke. Magnetic resonance fingerprinting (MRF) arterial spin labeling (ASL) is a novel noninvasive method of ASL perfusion that allows simultaneous estimation of cerebral blood flow (CBF), bolus arrival time (BAT), and tissue T1 map in a single scan of <4 minutes. Here, we evaluated the utility of MRF-ASL in patients with ischemic stroke in terms of detecting hemodynamic and structural damage and predicting neurological deficits and disability. METHODS A total of 34 patients were scanned on 3T magnetic resonance imaging. MRF-ASL, standard single-delay pseudo-continuous ASL, T2-weighted, and diffusion magnetic resonance imaging were performed. Regions of interest of lesion and contralateral normal tissues were manually delineated. CBF (with 2 different compartmental models), BAT, and tissue T1 parameters were quantified. Cross-sectional linear regression analyses were performed to examine the relationship between MRF-ASL parameters and National Institutes of Health Stroke Scale (NIHSS) and modified Rankin Scale. Receiver operating characteristic analyses were performed to determine the utility of MRF-ASL in the classification of stroke lesion voxels. RESULTS MRF-ASL derived parameters revealed a significant difference between stroke lesion and contralateral normal regions of interest, in that lesion regions manifested a lower CBF1-compartment (P<0.001), lower CBF2-compartment (P<0.001), longer BAT (P=0.002), and longer T1 (P<0.001) compared with normal regions of interest. NIHSS scores at acute stage revealed a strong association with lesion-normal differences in CBF1-compartment,diff (β=-0.11, P=0.008), CBF2-compartment,diff (β=-0.16, P=0.003), and T1,diff (β=0.008, P=0.001). MRF-ASL parameters were also predictive of NIHSS score and modified Rankin Scale scale measured at a later stage, although the degree of the associations was weaker. These associations tended to be even stronger when the MRF-ASL data were acquired at the acute/subacute stage. Compared with standard pseudo-continuous ASL, the multiparametric capability of MRF-ASL yielded higher area under curve values in the receiver operating characteristic analyses of stroke voxel classifications. CONCLUSIONS MRF-ASL may provide a new approach for quantitative hemodynamic and structural imaging in ischemic stroke.
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Affiliation(s)
- Hongli Fan
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD. (H.F., H.L.).,The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD. (H.F., P.S., D.D.M.L., H.L.)
| | - Pan Su
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD. (H.F., P.S., D.D.M.L., H.L.)
| | - Doris Da May Lin
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD. (H.F., P.S., D.D.M.L., H.L.)
| | - Emily B Goldberg
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD. (E.B.G., A.W., R.L., A.E.H.)
| | - Alexandra Walker
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD. (E.B.G., A.W., R.L., A.E.H.)
| | - Richard Leigh
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD. (E.B.G., A.W., R.L., A.E.H.)
| | - Argye E Hillis
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD. (E.B.G., A.W., R.L., A.E.H.)
| | - Hanzhang Lu
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD. (H.F., H.L.).,The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD. (H.F., P.S., D.D.M.L., H.L.).,F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD (H.L.)
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6
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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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Lu J, Mei Q, Hou X, Manaenko A, Zhou L, Liebeskind DS, Zhang JH, Li Y, Hu Q. Imaging Acute Stroke: From One-Size-Fit-All to Biomarkers. Front Neurol 2021; 12:697779. [PMID: 34630278 PMCID: PMC8497192 DOI: 10.3389/fneur.2021.697779] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 06/30/2021] [Indexed: 12/27/2022] Open
Abstract
In acute stroke management, time window has been rigidly used as a guide for decades and the reperfusion treatment is only available in the first few limited hours. Recently, imaging-based selection of patients has successfully expanded the treatment window out to 16 and even 24 h in the DEFUSE 3 and DAWN trials, respectively. Recent guidelines recommend the use of imaging techniques to guide therapeutic decision-making and expanded eligibility in acute ischemic stroke. A tissue window is proposed to replace the time window and serve as the surrogate marker for potentially salvageable tissue. This article reviews the evolution of time window, addresses the advantage of a tissue window in precision medicine for ischemic stroke, and discusses both the established and emerging techniques of neuroimaging and their roles in defining a tissue window. We also emphasize the metabolic imaging and molecular imaging of brain pathophysiology, and highlight its potential in patient selection and treatment response prediction in ischemic stroke.
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Affiliation(s)
- Jianfei Lu
- Central Laboratory, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Qiyong Mei
- Department of Neurosurgery, Changzheng Hospital, Navy Medical University, Shanghai, China
| | - Xianhua Hou
- Department of Neurology, Southwest Hospital, Army Medical University, Chongqing, China
| | - Anatol Manaenko
- National Health Commission Key Laboratory of Diagnosis and Treatment on Brain Functional Diseases, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Lili Zhou
- Department of Neurology, Chinese People's Liberation Army General Hospital, Beijing, China
| | - David S Liebeskind
- Neurovascular Imaging Research Core and University of California Los Angeles Stroke Center, University of California, Los Angeles, Los Angeles, CA, United States
| | - John H Zhang
- Department of Anesthesiology, Loma Linda University School of Medicine, Loma Linda, CA, United States
| | - Yao Li
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Qin Hu
- Central Laboratory, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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Little PV, Arnberg F, Jussing E, Lu L, Ingemann Jensen A, Mitsios N, Mulder J, Tran TA, Holmin S. The cellular basis of increased PET hypoxia tracer uptake in focal cerebral ischemia with comparison between [ 18F]FMISO and [ 64Cu]CuATSM. J Cereb Blood Flow Metab 2021; 41:617-629. [PMID: 32423333 PMCID: PMC7922752 DOI: 10.1177/0271678x20923857] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 03/31/2020] [Accepted: 04/12/2020] [Indexed: 11/16/2022]
Abstract
PET hypoxia imaging can assess tissue viability in acute ischemic stroke (AIS). [18F]FMISO is an established tracer but requires substantial accumulation time, limiting its use in hyperacute AIS. [64Cu]CuATSM requires less accumulation time and has shown promise as a hypoxia tracer. We compared these tracers in a M2-occlusion model (M2CAO) with preserved collateral blood flow. Rats underwent M2CAO and [18F]FMISO (n = 12) or [64Cu]CuATSM (n = 6) examinations. [64Cu]CuATSM animals were also examined with MRI. Pimonidazole was used as a surrogate for [18F]FMISO in an immunofluorescence analysis employed to profile levels of hypoxia in neurons (NeuN) and astrocytes (GFAP). There was increased [18F]FMISO uptake in the M2CAO cortex. No increase in [64Cu]CuATSM activity was found. The pimonidazole intensity of neurons and astrocytes was increased in hypoxic regions. The pimonidazole intensity ratio was higher in neurons than in astrocytes. In the majority of animals, immunofluorescence revealed a loss of astrocytes within the core of regions with increased pimonidazole uptake. We conclude that [18F]FMISO is superior to [64Cu]CuATSM in detecting hypoxia in AIS, consistent with an earlier study. [18F]FMISO may provide efficient diagnostic imaging beyond the hyperacute phase. Results do not provide encouragement for the use of [64Cu]CuATSM in experimental AIS.
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Affiliation(s)
- Philip V Little
- The Department of Clinical Neuroscience, Karolinska Institutet,
Stockholm Sweden
- The Department of Neuroradiology, BioClinicum, Karolinska
University Hospital, Stockholm, Sweden
| | - Fabian Arnberg
- The Department of Clinical Neuroscience, Karolinska Institutet,
Stockholm Sweden
- The Department of Neuroradiology, BioClinicum, Karolinska
University Hospital, Stockholm, Sweden
| | - Emma Jussing
- The Department of Clinical Neuroscience, Karolinska Institutet,
Stockholm Sweden
- The Department of Radiopharmacy, Karolinska University Hospital,
Stockholm, Sweden
- The Department of Oncology and Pathology, Karolinska Institutet,
Stockholm Sweden
| | - Li Lu
- The Department of Clinical Neuroscience, Karolinska Institutet,
Stockholm Sweden
- The Department of Radiopharmacy, Karolinska University Hospital,
Stockholm, Sweden
- The Department of Oncology and Pathology, Karolinska Institutet,
Stockholm Sweden
| | | | - Nicholas Mitsios
- The Department of Neuroscience, Karolinska Institutet,
Stockholm, Sweden
| | - Jan Mulder
- The Department of Neuroscience, Karolinska Institutet,
Stockholm, Sweden
| | - Thuy A Tran
- The Department of Clinical Neuroscience, Karolinska Institutet,
Stockholm Sweden
- The Department of Radiopharmacy, Karolinska University Hospital,
Stockholm, Sweden
- The Department of Oncology and Pathology, Karolinska Institutet,
Stockholm Sweden
| | - Staffan Holmin
- The Department of Clinical Neuroscience, Karolinska Institutet,
Stockholm Sweden
- The Department of Neuroradiology, BioClinicum, Karolinska
University Hospital, Stockholm, Sweden
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9
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Li Y, Wang T, Zhang T, Lin Z, Li Y, Guo R, Zhao Y, Meng Z, Liu J, Yu X, Liang ZP, Nachev P. Fast high-resolution metabolic imaging of acute stroke with 3D magnetic resonance spectroscopy. Brain 2020; 143:3225-3233. [PMID: 33141145 PMCID: PMC7719019 DOI: 10.1093/brain/awaa264] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 06/05/2020] [Accepted: 06/29/2020] [Indexed: 01/24/2023] Open
Abstract
Impaired oxygen and cellular metabolism is a hallmark of ischaemic injury in acute stroke. Magnetic resonance spectroscopic imaging (MRSI) has long been recognized as a potentially powerful tool for non-invasive metabolic imaging. Nonetheless, long acquisition time, poor spatial resolution, and narrow coverage have limited its clinical application. Here we investigated the feasibility and potential clinical utility of rapid, high spatial resolution, near whole-brain 3D metabolic imaging based on a novel MRSI technology. In an 8-min scan, we simultaneously obtained 3D maps of N-acetylaspartate and lactate at a nominal spatial resolution of 2.0 × 3.0 × 3.0 mm3 with near whole-brain coverage from a cohort of 18 patients with acute ischaemic stroke. Serial structural and perfusion MRI was used to define detailed spatial maps of tissue-level outcomes against which high-resolution metabolic changes were evaluated. Within hypoperfused tissue, the lactate signal was higher in areas that ultimately infarcted compared with those that recovered (P < 0.0001). Both lactate (P < 0.0001) and N-acetylaspartate (P < 0.001) differed between infarcted and other regions. Within the areas of diffusion-weighted abnormality, lactate was lower where recovery was observed compared with elsewhere (P < 0.001). This feasibility study supports further investigation of fast high-resolution MRSI in acute stroke.
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Affiliation(s)
- Yao Li
- Institute for Medical Imaging Technology, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Tianyao Wang
- Radiology Department, Shanghai Fifth People’s Hospital, Fudan University, Shanghai, China
| | - Tianxiao Zhang
- Institute for Medical Imaging Technology, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Zengping Lin
- Institute for Medical Imaging Technology, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Yudu Li
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Rong Guo
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Yibo Zhao
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Ziyu Meng
- Institute for Medical Imaging Technology, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Jun Liu
- Radiology Department, Shanghai Fifth People’s Hospital, Fudan University, Shanghai, China
| | - Xin Yu
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
| | - Zhi-Pei Liang
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Parashkev Nachev
- High-Dimensional Neurology Group, Institute of Neurology, University College London, London, UK
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10
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Abstract
The discovery that brain tissue could potentially be salvaged from ischaemia due to stroke, has led to major advances in the development of therapies for ischemic stroke. In this review, we detail the advances in the understanding of this area termed the ischaemic penumbra, from its discovery to the evolution of imaging techniques, and finally some of the treatments developed. Evolving from animal studies from the 70s and 80s and translated to clinical practice, the field of ischemic reperfusion therapy has largely been guided by an array of imaging techniques developed to positively identify the ischemic penumbra, including positron emission tomography, computed tomography and magnetic resonance imaging. More recently, numerous penumbral identification imaging studies have allowed for a better understanding of the progression of the ischaemic core at the expense of the penumbra, and identification of patients than can benefit from reperfusion therapies in the acute phase. Importantly, 40 years of critical imaging research on the ischaemic penumbra have allowed for considerable extension of the treatment time window and better patient selection for reperfusion therapy. The translation of the penumbra concept into routine clinical practice has shown that "tissue is at least as important as time."
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Affiliation(s)
- Charlotte M Ermine
- Florey Institute of Neuroscience and Mental Health, Melbourne, Australia
| | - Andrew Bivard
- Department of Medicine, Melbourne Brain Centre at The Royal Melbourne Hospital, Parkville, Australia.,Department of Neurology, Melbourne Brain Centre at The Royal Melbourne Hospital, Parkville, Australia
| | - Mark W Parsons
- Department of Medicine, Melbourne Brain Centre at The Royal Melbourne Hospital, Parkville, Australia.,Department of Neurology, Melbourne Brain Centre at The Royal Melbourne Hospital, Parkville, Australia
| | - Jean-Claude Baron
- Institute of Psychiatry and Neuroscience of Paris (IPNP), Université de Paris, Paris, France.,GHU Paris Psychiatrie et Neurosciences, Hôpital Sainte Anne, Paris, France
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11
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Little PV, Kraft SE, Chireh A, Damberg P, Holmin S. Oxygen metabolism MRI - A comparison with perfusion imaging in a rat model of MCA branch occlusion and reperfusion. J Cereb Blood Flow Metab 2020; 40:2315-2327. [PMID: 31842668 PMCID: PMC7585917 DOI: 10.1177/0271678x19892271] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 10/29/2019] [Accepted: 11/01/2019] [Indexed: 11/17/2022]
Abstract
The penumbra is sustained by an increased extraction of oxygen (OEF) from blood to brain tissue. Metabolic imaging may improve penumbra specificity when examining stroke patients with wake-up stroke and a long time between admission and symptom onset. We used MRI to examine OEF, and compared the volume of regions with elevated OEF to the volume of regions with perfusion deficit in a M2 occlusion model (M2CAO) with preserved collateral blood flow. OEF was calculated from BOLD MRI examining tissue R2', with ASL perfusion imaging employed to determine cerebral blood flows (CBF) and volumes. Diffusion imaging was used to identify the ischemic core (IC). Examinations were performed during and after transient M2CAO in rats. The IC-OEF mismatch was significantly smaller than the IC-CBF mismatch during M2CAO. The penumbra OEF was significantly increased during M2CAO, and decreased significantly after reperfusion. The IC-OEF mismatch may provide increased penumbra specificity compared to IC-CBF mismatch regimens. Results strongly indicate the potential of metabolic MRI for thrombectomy patient selection in cases with a long time from symptom onset to admission. Results demonstrate the effectiveness of reperfusion in alleviating metabolic disturbances in ischemic regions, emphasizing fast treatment to achieve significant neurological recovery in stroke patients.
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Affiliation(s)
- Philip V Little
- Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
- Department of Neuroradiology, BioClinicum, Karolinska University Hospital, Stockholm, Sweden
| | - Sandra E Kraft
- Karolinska Experimental Research and Imaging Center (KERIC), Karolinska University Hospital-Solna, Stockholm, Sweden
| | - Arvin Chireh
- Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
- Department of Neuroradiology, BioClinicum, Karolinska University Hospital, Stockholm, Sweden
| | - Peter Damberg
- Karolinska Experimental Research and Imaging Center (KERIC), Karolinska University Hospital-Solna, Stockholm, Sweden
| | - Staffan Holmin
- Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
- Department of Neuroradiology, BioClinicum, Karolinska University Hospital, Stockholm, Sweden
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12
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Zhang S, Cho J, Nguyen TD, Spincemaille P, Gupta A, Zhu W, Wang Y. Initial Experience of Challenge-Free MRI-Based Oxygen Extraction Fraction Mapping of Ischemic Stroke at Various Stages: Comparison With Perfusion and Diffusion Mapping. Front Neurosci 2020; 14:535441. [PMID: 33041755 PMCID: PMC7525031 DOI: 10.3389/fnins.2020.535441] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Accepted: 08/18/2020] [Indexed: 01/01/2023] Open
Abstract
MRI-based oxygen extraction fraction imaging has a great potential benefit in the selection of clinical strategies for ischemic stroke patients. This study aimed to evaluate the performance of a challenge-free oxygen extraction fraction (OEF) mapping in a cohort of acute and subacute ischemic stroke patients. Consecutive ischemic stroke patients (a total of 30 with 5 in the acute stage, 19 in the early subacute stage, and 6 in the late subacute stage) were recruited. All subjects underwent MRI including multi-echo gradient echo (mGRE), diffusion weighted imaging (DWI), and 3D-arterial spin labeling (ASL). OEF maps were generated from mGRE phase + magnitude data, which were processed using quantitative susceptibility mapping (QSM) + quantitative blood oxygen level-dependent (qBOLD) imaging with cluster analysis of time evolution. Cerebral blood flow (CBF) and apparent diffusion coefficient (ADC) maps were reconstructed from 3D-ASL and DWI, respectively. Further, cerebral metabolic rate of oxygen (CMRO2) was calculated as the product of CBF and OEF. OEF, CMRO2, CBF, and ADC values in the ischemic cores (absolute values) and their contrasts to the contralateral regions (relative values) were evaluated. One-way analysis of variance (ANOVA) was used to compare OEF, CMRO2, CBF, and ADC values and their relative values among different stroke stages. The OEF value of infarct core showed a trend of decrease from acute, to early subacute, and to late subacute stages of ischemic stroke. Significant differences among the three stroke stages were only observed in the absolute OEF (F = 6.046, p = 0.005) and relative OEF (F = 5.699, p = 0.009) values of the ischemic core, but not in other measurements (absolute and relative CMRO2, CBF, ADC values, all values of p > 0.05). In conclusion, the challenge-free QSM + qBOLD-generated OEF mapping can be performed on stroke patients. It can provide more information on tissue viability that was not available with CBF and ADC and, thus, may help to better manage ischemic stroke patients.
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Affiliation(s)
- Shun Zhang
- Department of Radiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Junghun Cho
- Department of Radiology, Weill Cornell Medicine, New York, NY, United States
- Department of Biomedical Engineering, Cornell University, Ithaca, NY, United States
| | - Thanh D. Nguyen
- Department of Radiology, Weill Cornell Medicine, New York, NY, United States
| | - Pascal Spincemaille
- Department of Radiology, Weill Cornell Medicine, New York, NY, United States
| | - Ajay Gupta
- Department of Radiology, Weill Cornell Medicine, New York, NY, United States
| | - Wenzhen Zhu
- Department of Radiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yi Wang
- Department of Radiology, Weill Cornell Medicine, New York, NY, United States
- Department of Biomedical Engineering, Cornell University, Ithaca, NY, United States
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13
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Kuo DP, Kuo PC, Chen YC, Kao YCJ, Lee CY, Chung HW, Chen CY. Machine learning-based segmentation of ischemic penumbra by using diffusion tensor metrics in a rat model. J Biomed Sci 2020; 27:80. [PMID: 32664906 PMCID: PMC7362663 DOI: 10.1186/s12929-020-00672-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 07/09/2020] [Indexed: 01/01/2023] Open
Abstract
Background Recent trials have shown promise in intra-arterial thrombectomy after the first 6–24 h of stroke onset. Quick and precise identification of the salvageable tissue is essential for successful stroke management. In this study, we examined the feasibility of machine learning (ML) approaches for differentiating the ischemic penumbra (IP) from the infarct core (IC) by using diffusion tensor imaging (DTI)-derived metrics. Methods Fourteen male rats subjected to permanent middle cerebral artery occlusion (pMCAO) were included in this study. Using a 7 T magnetic resonance imaging, DTI metrics such as fractional anisotropy, pure anisotropy, diffusion magnitude, mean diffusivity (MD), axial diffusivity, and radial diffusivity were derived. The MD and relative cerebral blood flow maps were coregistered to define the IP and IC at 0.5 h after pMCAO. A 2-level classifier was proposed based on DTI-derived metrics to classify stroke hemispheres into the IP, IC, and normal tissue (NT). The classification performance was evaluated using leave-one-out cross validation. Results The IC and non-IC can be accurately segmented by the proposed 2-level classifier with an area under the receiver operating characteristic curve (AUC) between 0.99 and 1.00, and with accuracies between 96.3 and 96.7%. For the training dataset, the non-IC can be further classified into the IP and NT with an AUC between 0.96 and 0.98, and with accuracies between 95.0 and 95.9%. For the testing dataset, the classification accuracy for IC and non-IC was 96.0 ± 2.3% whereas for IP and NT, it was 80.1 ± 8.0%. Overall, we achieved the accuracy of 88.1 ± 6.7% for classifying three tissue subtypes (IP, IC, and NT) in the stroke hemisphere and the estimated lesion volumes were not significantly different from those of the ground truth (p = .56, .94, and .78, respectively). Conclusions Our method achieved comparable results to the conventional approach using perfusion–diffusion mismatch. We suggest that a single DTI sequence along with ML algorithms is capable of dichotomizing ischemic tissue into the IC and IP.
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Affiliation(s)
- Duen-Pang Kuo
- Department of Medical Imaging, Taipei Medical University Hospital, No.250, Wu-Hsing St, Taipei, 11031, Taiwan.,Department of Radiology, Taoyuan Armed Forces General Hospital, Taoyuan, Taiwan
| | - Po-Chih Kuo
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Yung-Chieh Chen
- Department of Medical Imaging, Taipei Medical University Hospital, No.250, Wu-Hsing St, Taipei, 11031, Taiwan
| | - Yu-Chieh Jill Kao
- Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, No.155, Sec.2, Linong St, Taipei, 11221, Taiwan
| | - Ching-Yen Lee
- TMU Center for Big Data and Artificial Intelligence in Medical Imaging, Taipei Medical University Hospital, Taipei, Taiwan.,TMU Research Center for Artificial Intelligence in Medicine, Taipei Medical University Hospital, Taipei, Taiwan
| | - Hsiao-Wen Chung
- Graduate Institute of Biomedical Electrics and Bioinformatics, National Taiwan University, Taipei, Taiwan
| | - Cheng-Yu Chen
- Department of Medical Imaging, Taipei Medical University Hospital, No.250, Wu-Hsing St, Taipei, 11031, Taiwan. .,Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, No.155, Sec.2, Linong St, Taipei, 11221, Taiwan. .,Department of Radiology, School of Medicine, College of Medicine, Taipei Medical University, No.250, Wu-Hsing St, Taipei, 11031, Taiwan. .,Radiogenomic Research Center, Taipei Medical University Hospital, No.250, Wu-Hsing St, Taipei, 11031, Taiwan. .,Center for Artificial Intelligence in Medicine, Taipei Medical University, No.250, Wu-Hsing St, Taipei, 11031, Taiwan. .,Department of Radiology, National Defense Medical Center, No.250, Wu-Hsing St, Taipei, 11031, Taiwan.
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14
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Optogenetic translocation of protons out of penumbral neurons is protective in a rodent model of focal cerebral ischemia. Brain Stimul 2020; 13:881-890. [PMID: 32289721 DOI: 10.1016/j.brs.2020.03.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2019] [Revised: 03/10/2020] [Accepted: 03/11/2020] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Intracellular acidosis in the ischemic penumbra can contribute to further cell death, effectively enlarging the infarct core. Restoring the acid-base balance may enhance tissue survivability after cerebral ischemia. OBJECTIVE This study investigated whether translocating protons out of penumbral neurons could mitigate tissue acidification and induce neuroprotection in a rodent model of acute cerebral ischemia. METHODS We modulated the penumbral neurons via a light-driven pump to translocate protons out (i.e., archaerhodopsin/ArchT group) or into (i.e., channelrhodopsin-2/ChR2 group) neurons after focal cerebral ischemia in rats. Intracellular pH values were imaged via neutral red (NR) fluorescence and cerebral blood flow (CBF) was monitored through laser speckle contrast imaging (LSCI). Global CBF responses to electrical stimulation of the hindlimbs were obtained 24 h and 48 h after ischemia to assess neurological function. Behavioral and histological outcomes were evaluated 48 h after ischemia. A control group without gene modification was included. RESULTS The reduction of relative pH (RpH), the amplitude of negative peak of hypoemic response (RNP) and the hemispheric lateralization index (LI) in ArchT group were significantly less than those of the ChR2 or control group. Moreover, RpH was strongly correlated with RNP (r = 0.60) and LI (r24h = 0.80, r48h = 0.59). In addition, behavioral and histological results supported a neuroprotective effect of countering neuronal acidosis in penumbra through optogenetic stimulation. CONCLUSION(S) These results indicate that countering intracellular acidosis by optogenetically translocating protons out of penumbral neurons during the acute ischemic stage could induce protection after ischemic brain injury.
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15
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Fan AP, Khalil AA, Fiebach JB, Zaharchuk G, Villringer A, Villringer K, Gauthier CJ. Elevated brain oxygen extraction fraction measured by MRI susceptibility relates to perfusion status in acute ischemic stroke. J Cereb Blood Flow Metab 2020; 40:539-551. [PMID: 30732551 PMCID: PMC7026852 DOI: 10.1177/0271678x19827944] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Recent clinical trials of new revascularization therapies in acute ischemic stroke have highlighted the importance of physiological imaging to identify optimal treatments for patients. Oxygen extraction fraction (OEF) is a hallmark of at-risk tissue in stroke, and can be quantified from the susceptibility effect of deoxyhemoglobin molecules in venous blood on MRI phase scans. We measured OEF within cerebral veins using advanced quantitative susceptibility mapping (QSM) MRI reconstructions in 20 acute stroke patients. Absolute OEF was elevated in the affected (29.3 ± 3.4%) versus the contralateral hemisphere (25.5 ± 3.1%) of patients with large diffusion-perfusion lesion mismatch (P = 0.032). In these patients, OEF negatively correlated with relative CBF measured by dynamic susceptibility contrast MRI (P = 0.004), suggesting compensation for reduced flow. Patients with perfusion-diffusion match or no hypo-perfusion showed less OEF difference between hemispheres. Nine patients received longitudinal assessment and showed OEF ratio (affected to contralateral) of 1.2 ± 0.1 at baseline that normalized (decreased) to 1.0 ± 0.1 at follow-up three days later (P = 0.03). Our feasibility study demonstrates that QSM MRI can non-invasively quantify OEF in stroke patients, relates to perfusion status, and is sensitive to OEF changes over time. Clinical trial registration: Longitudinal MRI examinations of patients with brain ischemia and blood brain barrier permeability; clinicaltrials.org :NCT02077582.
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Affiliation(s)
- Audrey P Fan
- Department of Radiology, Stanford University, Stanford, CA, USA
| | - Ahmed A Khalil
- Center for Stroke Research Berlin, Charité Universitätsmedizin Berlin, Berlin, Germany.,Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.,Berlin School of Mind and Brain, Humboldt-Universitaet zu Berlin, Berlin, Germany
| | - Jochen B Fiebach
- Center for Stroke Research Berlin, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Greg Zaharchuk
- Department of Radiology, Stanford University, Stanford, CA, USA
| | - Arno Villringer
- Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.,Berlin School of Mind and Brain, Humboldt-Universitaet zu Berlin, Berlin, Germany
| | - Kersten Villringer
- Center for Stroke Research Berlin, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Claudine J Gauthier
- Department of Physics, Concordia University, Montreal, Canada.,Montreal Heart Institute, Montreal, Canada
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16
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Yuan X, Rosenberg JT, Liu Y, Grant SC, Ma T. Aggregation of human mesenchymal stem cells enhances survival and efficacy in stroke treatment. Cytotherapy 2019; 21:1033-1048. [PMID: 31537468 DOI: 10.1016/j.jcyt.2019.04.055] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 04/12/2019] [Accepted: 04/15/2019] [Indexed: 12/13/2022]
Abstract
Human mesenchymal stem cells (hMSCs) have been shown to enhance stroke lesion recovery by mediating inflammation and tissue repair through secretion of trophic factors. However, low cell survival and reduced primitive stem cell function of culture-expanded hMSCs are the major challenges limiting hMSC therapeutic efficacy in stroke treatment. In this study, we report the effects of short-term preconditioning of hMSCs via three-dimensional (3D) aggregation on stroke lesion recovery after intra-arterial (IA) transplantation of 3D aggregate-derived hMSCs (Agg-D hMSCs) in a transient middle cerebral artery occlusion (MCAO) stroke model. Compared with two-dimensional (2D) monolayer culture, Agg-D hMSCs exhibited increased resistance to ischemic stress, secretory function and therapeutic outcome. Short-term preconditioning via 3D aggregation reconfigured hMSC energy metabolism and altered redox cycle, which activated the PI3K/AKT pathway and enhanced resistance to in vitro oxidative stress. Analysis of transplanted hMSCs in MCAO rats using ultra-high-field magnetic resonance imaging at 21.1 T showed increased hMSC persistence and stroke lesion reduction by sodium (23Na) imaging in the Agg-D hMSC group compared with 2D hMSC control. Behavioral analyses further revealed functional improvement in MCAO animal treated with Agg-D hMSCs compared with saline control. Together, the results demonstrated the improved outcome for Agg-D hMSCs in the MCAO model and suggest short-term 3D aggregation as an effective preconditioning strategy for hMSC functional enhancement in stroke treatment.
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Affiliation(s)
- Xuegang Yuan
- Department of Chemical and Biomedical Engineering; Florida State University, Tallahassee, Florida, USA
| | - Jens T Rosenberg
- Department of Chemical and Biomedical Engineering; Florida State University, Tallahassee, Florida, USA; The National High Magnetic Field Laboratory; Florida State University, Tallahassee, Florida, USA
| | - Yijun Liu
- Department of Chemical and Biomedical Engineering; Florida State University, Tallahassee, Florida, USA
| | - Samuel C Grant
- Department of Chemical and Biomedical Engineering; Florida State University, Tallahassee, Florida, USA; The National High Magnetic Field Laboratory; Florida State University, Tallahassee, Florida, USA.
| | - Teng Ma
- Department of Chemical and Biomedical Engineering; Florida State University, Tallahassee, Florida, USA
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17
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Zaro-Weber O, Fleischer H, Reiblich L, Schuster A, Moeller-Hartmann W, Heiss WD. Penumbra detection in acute stroke with perfusion magnetic resonance imaging: Validation with 15 O-positron emission tomography. Ann Neurol 2019; 85:875-886. [PMID: 30937950 PMCID: PMC6593670 DOI: 10.1002/ana.25479] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 03/20/2019] [Accepted: 03/31/2019] [Indexed: 12/17/2022]
Abstract
Objective Accurate identification of the ischemic penumbra, the therapeutic target in acute clinical stroke, is of critical importance to identify patients who might benefit from reperfusion therapies beyond the established time windows. Therefore, we aimed to validate magnetic resonance imaging (MRI) mismatch–based penumbra detection against full quantitative positron emission tomography (15O‐PET), the gold standard for penumbra detection in acute ischemic stroke. Methods Ten patients (group A) with acute and subacute ischemic stroke underwent perfusion‐weighted (PW)/diffusion‐weighted MRI and consecutive full quantitative 15O‐PET within 48 hours of stroke onset. Penumbra as defined by 15O‐PET cerebral blood flow (CBF), oxygen extraction fraction, and oxygen metabolism was used to validate a wide range of established PW measures (eg, time‐to‐maximum [Tmax]) to optimize penumbral tissue detection. Validation was carried out using a voxel‐based receiver‐operating‐characteristic curve analysis. The same validation based on penumbra as defined by quantitative 15O‐PET CBF was performed for comparative reasons in 23 patients measured within 48 hours of stroke onset (group B). Results The PW map Tmax (area‐under‐the‐curve = 0.88) performed best in detecting penumbral tissue up to 48 hours after stroke onset. The optimal threshold to discriminate penumbra from oligemia was Tmax >5.6 seconds with a sensitivity and specificity of >80%. Interpretation The performance of the best PW measure Tmax to detect the upper penumbral flow threshold in ischemic stroke is excellent. Tmax >5.6 seconds–based penumbra detection is reliable to guide treatment decisions up to 48 hours after stroke onset and might help to expand reperfusion treatment beyond the current time windows. ANN NEUROL 2019;85:875–886.
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Affiliation(s)
- Olivier Zaro-Weber
- Max Planck Institute for Neurological Research, Cologne, Germany.,Department of Neurology, Charité-Universitätsmedizin Berlin, Berlin, Germany.,Center for Stroke Research Berlin, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Hermann Fleischer
- Max Planck Institute for Neurological Research, Cologne, Germany.,Department of Neurology, Charité-Universitätsmedizin Berlin, Berlin, Germany.,Center for Stroke Research Berlin, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Lucas Reiblich
- Max Planck Institute for Neurological Research, Cologne, Germany.,Department of Neurology, Charité-Universitätsmedizin Berlin, Berlin, Germany.,Center for Stroke Research Berlin, Charité-Universitätsmedizin Berlin, Berlin, Germany
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18
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Seiler A, Blockley NP, Deichmann R, Nöth U, Singer OC, Chappell MA, Klein JC, Wagner M. The relationship between blood flow impairment and oxygen depletion in acute ischemic stroke imaged with magnetic resonance imaging. J Cereb Blood Flow Metab 2019; 39:454-465. [PMID: 28929836 PMCID: PMC6421246 DOI: 10.1177/0271678x17732448] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Oxygenation-sensitive spin relaxation time T2' and relaxation rate R2' (1/T2') are presumed to be markers of the cerebral oxygen extraction fraction (OEF) in acute ischemic stroke. In this study, we investigate the relationship of T2'/R2' with dynamic susceptibility contrast-based relative cerebral blood flow (rCBF) in acute ischemic stroke to assess their plausibility as surrogate markers of the ischemic penumbra. Twenty-one consecutive patients with internal carotid artery and/or middle cerebral artery occlusion were studied at 3.0 T. A physiological model of the cerebral vasculature (VM) was used to process PWI raw data in addition to a conventional deconvolution technique. T2', R2', and rCBF values were extracted from the ischemic core and hypoperfused areas. Within hypoperfused tissue, no correlation was found between deconvolved rCBF and T2' ( r = -0.05, p = 0.788), or R2' ( r = 0.039, p = 0.836). In contrast, we found a strong positive correlation with T2' ( r = 0.444, p = 0.006) and negative correlation with R2' ( r = -0.494, p = 0.0025) for rCBFVM, indicating increasing OEF with decreasing CBF and that rCBF based on the vascular model may be more closely related to metabolic disturbances. Further research to refine and validate these techniques may enable their use as MRI-based surrogate markers of the ischemic penumbra for selecting stroke patients for interventional treatment strategies.
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Affiliation(s)
- Alexander Seiler
- 1 Department of Neurology, Goethe University Frankfurt, Frankfurt, Germany
| | - Nicholas P Blockley
- 2 Nuffield Department of Clinical Neurosciences, Oxford Center for Functional MRI of the Brain, University of Oxford, Oxford, UK
| | - Ralf Deichmann
- 3 Brain Imaging Center, Goethe University Frankfurt, Frankfurt, Germany
| | - Ulrike Nöth
- 3 Brain Imaging Center, Goethe University Frankfurt, Frankfurt, Germany
| | - Oliver C Singer
- 1 Department of Neurology, Goethe University Frankfurt, Frankfurt, Germany
| | - Michael A Chappell
- 2 Nuffield Department of Clinical Neurosciences, Oxford Center for Functional MRI of the Brain, University of Oxford, Oxford, UK.,4 Department of Engineering Science, Institute of Biomedical Engineering, University of Oxford, Oxford, UK
| | - Johannes C Klein
- 5 Nuffield Department of Clinical Neurosciences, Oxford University, and Department of Neurology, Oxford University Hospitals NHS Trust, Oxford, UK
| | - Marlies Wagner
- 6 Institute of Neuroradiology, Goethe University Frankfurt, Frankfurt, Germany
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19
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20
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Engedal TS, Hjort N, Hougaard KD, Simonsen CZ, Andersen G, Mikkelsen IK, Boldsen JK, Eskildsen SF, Hansen MB, Angleys H, Jespersen SN, Pedraza S, Cho TH, Serena J, Siemonsen S, Thomalla G, Nighoghossian N, Fiehler J, Mouridsen K, Østergaard L. Transit time homogenization in ischemic stroke - A novel biomarker of penumbral microvascular failure? J Cereb Blood Flow Metab 2018; 38:2006-2020. [PMID: 28758524 PMCID: PMC6259320 DOI: 10.1177/0271678x17721666] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Cerebral ischemia causes widespread capillary no-flow in animal studies. The extent of microvascular impairment in human stroke, however, is unclear. We examined how acute intra-voxel transit time characteristics and subsequent recanalization affect tissue outcome on follow-up MRI in a historic cohort of 126 acute ischemic stroke patients. Based on perfusion-weighted MRI data, we characterized voxel-wise transit times in terms of their mean transit time (MTT), standard deviation (capillary transit time heterogeneity - CTH), and the CTH:MTT ratio (relative transit time heterogeneity), which is expected to remain constant during changes in perfusion pressure in a microvasculature consisting of passive, compliant vessels. To aid data interpretation, we also developed a computational model that relates graded microvascular failure to changes in these parameters. In perfusion-diffusion mismatch tissue, prolonged mean transit time (>5 seconds) and very low cerebral blood flow (≤6 mL/100 mL/min) was associated with high risk of infarction, largely independent of recanalization status. In the remaining mismatch region, low relative transit time heterogeneity predicted subsequent infarction if recanalization was not achieved. Our model suggested that transit time homogenization represents capillary no-flow. Consistent with this notion, low relative transit time heterogeneity values were associated with lower cerebral blood volume. We speculate that low RTH may represent a novel biomarker of penumbral microvascular failure.
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Affiliation(s)
- Thorbjørn S Engedal
- 1 Center of Functionally Integrative Neuroscience and MINDLab, Aarhus University, Aarhus University Hospital, Aarhus C, Denmark.,2 Department of Neuroradiology, Aarhus University Hospital, Nørrebrogade 44, 8000 Aarhus C, Denmark
| | - Niels Hjort
- 3 Department of Neurology Aarhus University Hospital, Aarhus C, Denmark
| | | | - Claus Z Simonsen
- 3 Department of Neurology Aarhus University Hospital, Aarhus C, Denmark
| | - Grethe Andersen
- 3 Department of Neurology Aarhus University Hospital, Aarhus C, Denmark
| | - Irene Klærke Mikkelsen
- 1 Center of Functionally Integrative Neuroscience and MINDLab, Aarhus University, Aarhus University Hospital, Aarhus C, Denmark
| | - Jens K Boldsen
- 1 Center of Functionally Integrative Neuroscience and MINDLab, Aarhus University, Aarhus University Hospital, Aarhus C, Denmark
| | - Simon F Eskildsen
- 1 Center of Functionally Integrative Neuroscience and MINDLab, Aarhus University, Aarhus University Hospital, Aarhus C, Denmark
| | - Mikkel B Hansen
- 1 Center of Functionally Integrative Neuroscience and MINDLab, Aarhus University, Aarhus University Hospital, Aarhus C, Denmark
| | - Hugo Angleys
- 1 Center of Functionally Integrative Neuroscience and MINDLab, Aarhus University, Aarhus University Hospital, Aarhus C, Denmark
| | - Sune N Jespersen
- 1 Center of Functionally Integrative Neuroscience and MINDLab, Aarhus University, Aarhus University Hospital, Aarhus C, Denmark.,4 Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | | | - Tae H Cho
- 6 Hospices Civils de Lyon, Lyon, France
| | | | | | - Götz Thomalla
- 7 University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
| | | | - Jens Fiehler
- 7 University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
| | - Kim Mouridsen
- 1 Center of Functionally Integrative Neuroscience and MINDLab, Aarhus University, Aarhus University Hospital, Aarhus C, Denmark
| | - Leif Østergaard
- 1 Center of Functionally Integrative Neuroscience and MINDLab, Aarhus University, Aarhus University Hospital, Aarhus C, Denmark.,2 Department of Neuroradiology, Aarhus University Hospital, Nørrebrogade 44, 8000 Aarhus C, Denmark
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Yuan T, Ren G, Quan G, Gao D. Fewer peripheral asymmetrical cortical veins is a predictor of favorable outcome in MCA infarctions with SWI-DWI mismatch. J Magn Reson Imaging 2018; 48:964-970. [PMID: 29424126 DOI: 10.1002/jmri.25965] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 01/20/2018] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND Outcome prediction of asymmetrical prominent cortical veins (APCVs) on infarction is still debated and may help in selecting patients for reperfusion treatment. PURPOSE To explore the relationship between fewer peripheral APCVs and the outcome in the patients of acute/subacute middle cerebral artery (MCA) infarctions as well as the relationship between this sign and stenosis of ipsilateral MCA. STUDY TYPE Retrospective case-control study. POPULATION We enrolled 41 patients with MCA acute/subacute infarction. Compared to the low sign of cortical veins of contralateral hemisphere on susceptibility-weighted imaging (SWI), these patients were divided into fewer (n = 28) and prominent APCVs (n = 13) groups. FIELD STRENGTH/SEQUENCE 3.0T conventional stroke sequences, including T1 -weighted imaging, T2 -weighted imaging, fluid-attenuated inversion recovery (FLAIR), diffusion-weighted imaging (DWI) (b = 0 and 1000 s/mm2 ), MR angiography (MRA), and SWI. ASSESSMENT We explored the relationships between fewer peripheral APCVs sign and clinical outcome, as well as the relationship between this sign and the degree of ipsilateral MCA stenosis. STATISTICAL TESTS Fisher's exact analysis, logistical regression, as well as Cohen's kappa coefficient were used for statistical analysis. RESULTS Fewer and prominent peripheral APCVs were detected in 28 (56.10%) and 13 (43.90%) patients. In 28 patients with fewer peripheral APCVs, 23 patients (82.14%) had a favorable outcome (modified Rankin Scale [mRS] ≤2), and five patients (17.76%) had an unfavorable outcome (mRS >2) (P = 0.010). In terms of MCA stenosis, the rate of normal and mild to moderate stenosis of MCA in the fewer APCVs group (82.14%) was higher than that in the prominent APCVs group (23.08%) (P < 0.001). More severe stenosis of ipsilateral MCA was found in patients with prominent APCVs group (76.92%) than that of fewer APCVs group (17.86%). The peripheral APCVs was positively correlated with the degree of MCA stenosis (r = 0.538, P < 0.001). DATA CONCLUSION Fewer peripheral APCVs may suggest a favorable outcome in unilateral MCA infarction. The patency of ipsilateral MCA may correlate to fewer APCVs and favorable outcome. LEVEL OF EVIDENCE 3 Technical Efficacy: Stage 5 J. Magn. Reson. Imaging 2018;48:964-970.
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Affiliation(s)
- Tao Yuan
- Department of Medical Imaging, The Second Hospital of Hebei Medical University, Shijiazhuang, China
| | - Guoli Ren
- Department of Medical Imaging, Liaocheng Pepople's Hospital, Liaocheng, China
| | - Guanmin Quan
- Department of Medical Imaging, The Second Hospital of Hebei Medical University, Shijiazhuang, China
| | - Duo Gao
- Department of Medical Imaging, The Second Hospital of Hebei Medical University, Shijiazhuang, China
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22
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Diffusion-Weighted MRI Stroke Volume Following Recanalization Treatment is Threshold-Dependent. Clin Neuroradiol 2017; 29:135-141. [PMID: 29051996 DOI: 10.1007/s00062-017-0634-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Accepted: 09/21/2017] [Indexed: 01/19/2023]
Abstract
PURPOSE Infarct lesion segmentation has been problematic as there are a wide range of relative and absolute diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) thresholds that have been used for this purpose. We examined differences of stroke lesion volume and evolution evaluated by magnetic resonance imaging (MRI) during the immediate post-treatment phase (<5 h) and at 24 h. METHODS In this study 33 acute ischemic stroke patients were imaged with MRI <5 h and 24 h post-reperfusion treatment. Lesion volumes were segmented on ADC maps and average DWI using literature cited absolute ADC and relative DWI thresholds. The segmented lesion volumes within both time points were compared and the absolute change in lesion volume (infarct growth) between the two time points was calculated and compared using Bland-Altman analysis. RESULTS Lesion volumes differed significantly when different relative DWI or absolute ADC thresholds were used (p < 0.05), which held true for baseline as well as follow-up lesions. The median absolute changes in lesion volume from baseline to follow-up for ADC thresholds of 550 × 10-6 mm2/s, 600 × 10-6 mm2/s, 630 × 10-6 mm2/s and 650 × 10-6 mm2/s were 3.5 ml, 4.2 ml, 4.5 ml, and 6.5 ml, respectively (p < 0.05). Likewise, the median absolute changes in lesion volume from baseline to follow-up for DWI thresholds, k = 0.85, 1.28, 1.64, 1.96, and 2.7 were 10.1 ml, 7.3 ml, 5.7 ml, 5.4 ml and 4.2 ml, respectively (p < 0.05). CONCLUSION Absolute lesion volumes and changes in lesion volumes (infarct growth) measured after recanalization treatment were dependent on absolute ADC and relative DWI thresholds, which may have clinical significance. Standardization of techniques for measuring DWI lesion volumes requires immediate attention.
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24
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Kurzhunov D, Borowiak R, Reisert M, Joachim Krafft A, Caglar Özen A, Bock M. 3D CMRO 2 mapping in human brain with direct 17O MRI: Comparison of conventional and proton-constrained reconstructions. Neuroimage 2017; 155:612-624. [PMID: 28527792 DOI: 10.1016/j.neuroimage.2017.05.029] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2017] [Revised: 05/12/2017] [Accepted: 05/15/2017] [Indexed: 10/19/2022] Open
Abstract
Oxygen metabolism is altered in brain tumor regions and is quantified by the cerebral metabolic rate of oxygen consumption (CMRO2). Direct dynamic 17O MRI with inhalation of isotopically enriched 17O2 gas can be used to quantify CMRO2; however, pixel-wise CMRO2 quantification in human brain is challenging due to low natural abundance of 17O isotope and, thus, the low signal-to-noise ratio (SNR) of 17O MR images. To test the feasibility CMRO2 mapping at a clinical 3 T MRI system, a new iterative reconstruction was proposed, which uses the edge information contained in a co-registered 1H gradient image to construct a non-homogeneous anisotropic diffusion (AD) filter. AD-constrained reconstruction of 17O MR images was compared to conventional Kaiser-Bessel gridding without and with Hanning filtering, and to iterative reconstruction with a total variation (TV) constraint. For numerical brain phantom and in two in vivo data sets of one healthy volunteer, AD-constrained reconstruction provided 17O images with improved resolution of fine brain structures and resulted in higher SNR. CMRO2 values of 0.78 - 1.55µmol/gtissue/min (white brain matter) and 1.03 - 2.01µmol/gtissue/min (gray brain matter) as well as the CMRO2 maps are in a good agreement with the results of 15O-PET and 17O MRI at 7 T and at 9.4 T. In conclusion, the proposed AD-constrained reconstruction enabled calculation of 3D CMRO2 maps at 3 T MRI system, which is an essential step towards clinical translation of 17O MRI for non-invasive CMRO2 quantification in tumor patients.
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Affiliation(s)
- Dmitry Kurzhunov
- Dept. of Radiology, Medical Physics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
| | - Robert Borowiak
- Dept. of Radiology, Medical Physics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany; German Cancer Consortium (DKTK), Heidelberg, Germany; German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Marco Reisert
- Dept. of Radiology, Medical Physics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Axel Joachim Krafft
- Dept. of Radiology, Medical Physics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Ali Caglar Özen
- Dept. of Radiology, Medical Physics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Michael Bock
- Dept. of Radiology, Medical Physics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
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25
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Seiler A, Deichmann R, Nöth U, Pfeilschifter W, Berkefeld J, Singer OC, Klein JC, Wagner M. Oxygenation-Sensitive Magnetic Resonance Imaging in Acute Ischemic Stroke Using T2'/R2' Mapping: Influence of Relative Cerebral Blood Volume. Stroke 2017; 48:1671-1674. [PMID: 28455319 DOI: 10.1161/strokeaha.117.017086] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 02/16/2017] [Accepted: 03/08/2017] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE Quantitative T2'/R2' mapping detect locally increased concentrations of deoxygenated hemoglobin-causing a decrease of T2' and increase of R2'-and might reflect increased cerebral oxygen extraction fraction. Because increases of (relative) cerebral blood volume (rCBV) may influence T2' and R2' through accumulation of deoxygenated hemoglobin, we aimed to investigate the impact of rCBV on T2'/R2' in patients with ischemic stroke. METHODS Data from patients with acute internal carotid artery and middle cerebral artery occlusion were analyzed. T2', R2', and rCBV were measured within the ischemic core, slightly and severely hypoperfused areas, and their relationship was examined. RESULTS A strong negative correlation with rCBV was found for R2' (r=-0.544; P=0.002), and T2' correlated positively with rCBV (r=0.546; P=0.001) in time-to-peak-delayed areas. T2'/R2' within hypoperfused tissue remained unchanged at normal or elevated rCBV levels. CONCLUSIONS T2' decrease/R2' increase within hypoperfused areas in ischemic stroke is not caused by local elevations of rCBV but most probably only by increased cerebral oxygen extraction fraction. However, considering rCBV is crucial to assess extent of oxygen extraction fraction changes by means of T2'/R2'.
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Affiliation(s)
- Alexander Seiler
- From the Department of Neurology (A.S., W.P., O.C.S.), Brain Imaging Center and Institute of Neuroradiology (R.D., U.N.), and Institute of Neuroradiology (J.B., M.W.), Goethe University Frankfurt, Germany; Nuffield Department of Clinical Neurosciences, Oxford University, United Kingdom (J.C.K.); and Department of Neurology, Oxford University Hospitals NHS Trust, United Kingdom (J.C.K.).
| | - Ralf Deichmann
- From the Department of Neurology (A.S., W.P., O.C.S.), Brain Imaging Center and Institute of Neuroradiology (R.D., U.N.), and Institute of Neuroradiology (J.B., M.W.), Goethe University Frankfurt, Germany; Nuffield Department of Clinical Neurosciences, Oxford University, United Kingdom (J.C.K.); and Department of Neurology, Oxford University Hospitals NHS Trust, United Kingdom (J.C.K.)
| | - Ulrike Nöth
- From the Department of Neurology (A.S., W.P., O.C.S.), Brain Imaging Center and Institute of Neuroradiology (R.D., U.N.), and Institute of Neuroradiology (J.B., M.W.), Goethe University Frankfurt, Germany; Nuffield Department of Clinical Neurosciences, Oxford University, United Kingdom (J.C.K.); and Department of Neurology, Oxford University Hospitals NHS Trust, United Kingdom (J.C.K.)
| | - Waltraud Pfeilschifter
- From the Department of Neurology (A.S., W.P., O.C.S.), Brain Imaging Center and Institute of Neuroradiology (R.D., U.N.), and Institute of Neuroradiology (J.B., M.W.), Goethe University Frankfurt, Germany; Nuffield Department of Clinical Neurosciences, Oxford University, United Kingdom (J.C.K.); and Department of Neurology, Oxford University Hospitals NHS Trust, United Kingdom (J.C.K.)
| | - Joachim Berkefeld
- From the Department of Neurology (A.S., W.P., O.C.S.), Brain Imaging Center and Institute of Neuroradiology (R.D., U.N.), and Institute of Neuroradiology (J.B., M.W.), Goethe University Frankfurt, Germany; Nuffield Department of Clinical Neurosciences, Oxford University, United Kingdom (J.C.K.); and Department of Neurology, Oxford University Hospitals NHS Trust, United Kingdom (J.C.K.)
| | - Oliver C Singer
- From the Department of Neurology (A.S., W.P., O.C.S.), Brain Imaging Center and Institute of Neuroradiology (R.D., U.N.), and Institute of Neuroradiology (J.B., M.W.), Goethe University Frankfurt, Germany; Nuffield Department of Clinical Neurosciences, Oxford University, United Kingdom (J.C.K.); and Department of Neurology, Oxford University Hospitals NHS Trust, United Kingdom (J.C.K.)
| | - Johannes C Klein
- From the Department of Neurology (A.S., W.P., O.C.S.), Brain Imaging Center and Institute of Neuroradiology (R.D., U.N.), and Institute of Neuroradiology (J.B., M.W.), Goethe University Frankfurt, Germany; Nuffield Department of Clinical Neurosciences, Oxford University, United Kingdom (J.C.K.); and Department of Neurology, Oxford University Hospitals NHS Trust, United Kingdom (J.C.K.)
| | - Marlies Wagner
- From the Department of Neurology (A.S., W.P., O.C.S.), Brain Imaging Center and Institute of Neuroradiology (R.D., U.N.), and Institute of Neuroradiology (J.B., M.W.), Goethe University Frankfurt, Germany; Nuffield Department of Clinical Neurosciences, Oxford University, United Kingdom (J.C.K.); and Department of Neurology, Oxford University Hospitals NHS Trust, United Kingdom (J.C.K.)
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26
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Buch S, Ye Y, Haacke EM. Quantifying the changes in oxygen extraction fraction and cerebral activity caused by caffeine and acetazolamide. J Cereb Blood Flow Metab 2017; 37:825-836. [PMID: 27029391 PMCID: PMC5363462 DOI: 10.1177/0271678x16641129] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A quantitative estimate of cerebral blood oxygen saturation is of critical importance in the investigation of cerebrovascular disease. We aimed to measure the change in venous oxygen saturation (Yv) before and after the intake of the vaso-dynamic agents caffeine and acetazolamide with high spatial resolution using susceptibility mapping. Caffeine and acetazolamide were administered on separate days to five healthy volunteers to measure the change in oxygen extraction fraction. The internal streaking artifacts in the susceptibility maps were reduced by giving an initial susceptibility value uniformly to the structure-of-interest, based on a priori information. Using this technique, Yv for normal physiological conditions, post-caffeine and post-acetazolamide was measured inside the internal cerebral veins as YNormal = 69.1 ± 3.3%, YCaffeine = 60.5 ± 2.8%, and YAcet = 79.1 ± 4.0%. This suggests that susceptibility mapping can serve as a sensitive biomarker for measuring reductions in cerebro-vascular reserve through abnormal vascular response. The percentage change in oxygen extraction fraction for caffeine and acetazolamide were found to be +27.0 ± 3.8% and -32.6 ± 2.1%, respectively. Similarly, the relative changes in cerebral blood flow in the presence of caffeine and acetazolamide were found to be -30.3% and + 31.5%, suggesting that the cerebral metabolic rate of oxygen remains stable between normal and challenged brain states for healthy subjects.
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Affiliation(s)
- Sagar Buch
- The MRI Institute for Biomedical Research, Waterloo, Canada
| | - Yongquan Ye
- Department of Radiology, Wayne State University, Detroit, USA
| | - E Mark Haacke
- The MRI Institute for Biomedical Research, Waterloo, Canada
- Department of Radiology, Wayne State University, Detroit, USA
- E. Mark Haacke, Radiology Department, Wayne State University, Detroit, Michigan 48201, USA.
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27
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Ward PGD, Fan AP, Raniga P, Barnes DG, Dowe DL, Ng ACL, Egan GF. Improved Quantification of Cerebral Vein Oxygenation Using Partial Volume Correction. Front Neurosci 2017; 11:89. [PMID: 28289372 PMCID: PMC5326785 DOI: 10.3389/fnins.2017.00089] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 02/10/2017] [Indexed: 11/25/2022] Open
Abstract
Purpose: Quantitative susceptibility mapping (QSM) enables cerebral venous characterization and physiological measurements, such as oxygen extraction fraction (OEF). The exquisite sensitivity of QSM to deoxygenated blood makes it possible to image small veins; however partial volume effects must be addressed for accurate quantification. We present a new method, Iterative Cylindrical Fitting (ICF), to estimate voxel-based partial volume effects for susceptibility maps and use it to improve OEF quantification of small veins with diameters between 1.5 and 4 voxels. Materials and Methods: Simulated QSM maps were generated to assess the performance of the ICF method over a range of vein geometries with varying echo times and noise levels. The ICF method was also applied to in vivo human brain data to assess the feasibility and behavior of OEF measurements compared to the maximum intensity voxel (MIV) method. Results: Improved quantification of OEF measurements was achieved for vessels with contrast to noise greater than 3.0 and vein radii greater than 0.75 voxels. The ICF method produced improved quantitative accuracy of OEF measurement compared to the MIV approach (mean OEF error 7.7 vs. 12.4%). The ICF method provided estimates of vein radius (mean error <27%) and partial volume maps (root mean-squared error <13%). In vivo results demonstrated consistent estimates of OEF along vein segments. Conclusion: OEF quantification in small veins (1.5–4 voxels in diameter) had lower error when using partial volume estimates from the ICF method.
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Affiliation(s)
- Phillip G D Ward
- Monash Biomedical Imaging, Monash UniversityClayton, VIC, Australia; Faculty of Information Technology, Monash UniversityClayton, VIC, Australia
| | - Audrey P Fan
- Department of Radiology, Lucas Center for Imaging, Stanford University Stanford, CA, USA
| | - Parnesh Raniga
- Monash Biomedical Imaging, Monash UniversityClayton, VIC, Australia; The Australian eHealth Research Centre, CSIRO Health and BiosecurityHerston, QLD, Australia
| | - David G Barnes
- Faculty of Information Technology, Monash UniversityClayton, VIC, Australia; Monash eResearch Centre, Monash UniversityClayton, VIC, Australia
| | - David L Dowe
- Faculty of Information Technology, Monash University Clayton, VIC, Australia
| | - Amanda C L Ng
- Department of Anatomy and Neuroscience, The University of Melbourne Melbourne, VIC, Australia
| | - Gary F Egan
- Monash Biomedical Imaging, Monash UniversityClayton, VIC, Australia; ARC Centre of Excellence for Integrative Brain FunctionMelbourne, VIC, Australia
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Livne M, Madai VI, Brunecker P, Zaro-Weber O, Moeller-Hartmann W, Heiss WD, Mouridsen K, Sobesky J. A PET-Guided Framework Supports a Multiple Arterial Input Functions Approach in DSC-MRI in Acute Stroke. J Neuroimaging 2017; 27:486-492. [PMID: 28207200 DOI: 10.1111/jon.12428] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2016] [Accepted: 01/02/2017] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND AND PURPOSE In acute stroke, arterial-input-function (AIF) determination is essential for obtaining perfusion estimates with dynamic susceptibility-weighted contrast-enhanced magnetic resonance imaging (DSC-MRI). Standard DSC-MRI postprocessing applies single AIF selection, ie, global AIF. Physiological considerations, however, suggest that a multiple AIFs selection method would improve perfusion estimates to detect penumbral flow. In this study, we developed a framework based on comparable DSC-MRI and positron emission tomography (PET) images to compare the two AIF selection approaches and assess their performance in penumbral flow detection in acute stroke. METHODS In a retrospective analysis of 17 sub(acute) stroke patients with consecutive MRI and PET scans, voxel-wise optimized AIFs were calculated based on the kinetic model as derived from both imaging modalities. Perfusion maps were calculated based on the optimized-AIF using two methodologies: (1) Global AIF and (2) multiple AIFs as identified by cluster analysis. Performance of penumbral-flow detection was tested by receiver-operating characteristics (ROC) curve analysis, ie, the area under the curve (AUC). RESULTS Large variation of optimized AIFs across brain voxels demonstrated that there is no optimal single AIF. Subsequently, the multiple-AIF method (AUC range over all maps: .82-.90) outperformed the global AIF methodology (AUC .72-.85) significantly. CONCLUSIONS We provide PET imaging-based evidence that a multiple AIF methodology is beneficial for penumbral flow detection in comparison with the standard global AIF methodology in acute stroke.
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Affiliation(s)
- Michelle Livne
- Center for Stroke Research Berlin (CSB), Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Vince I Madai
- Center for Stroke Research Berlin (CSB), Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Peter Brunecker
- Center for Stroke Research Berlin (CSB), Charité - Universitätsmedizin Berlin, Berlin, Germany
| | | | | | | | - Kim Mouridsen
- Center of Functionally Integrative Neuroscience, Aarhus University, Denmark
| | - Jan Sobesky
- Center for Stroke Research Berlin (CSB), Charité - Universitätsmedizin Berlin, Berlin, Germany
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Giacalone M, Frindel C, Robini M, Cervenansky F, Grenier E, Rousseau D. Robustness of spatio-temporal regularization in perfusion MRI deconvolution: An application to acute ischemic stroke. Magn Reson Med 2016; 78:1981-1990. [PMID: 28019027 DOI: 10.1002/mrm.26573] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 11/16/2016] [Accepted: 11/16/2016] [Indexed: 12/23/2022]
Abstract
PURPOSE The robustness of a recently introduced globally convergent deconvolution algorithm with temporal and edge-preserving spatial regularization for the deconvolution of dynamic susceptibility contrast perfusion magnetic resonance imaging is assessed in the context of ischemic stroke. THEORY AND METHODS Ischemic tissues are not randomly distributed in the brain but form a spatially organized entity. The addition of a spatial regularization term allows to take into account this spatial organization contrarily to the sole temporal regularization approach which processes each voxel independently. The robustness of the spatial regularization in relation to shape variability, hemodynamic variability in tissues, noise in the magnetic resonance imaging apparatus, and uncertainty on the arterial input function selected for the deconvolution is addressed via an original in silico validation approach. RESULTS The deconvolution algorithm proved robust to the different sources of variability, outperforming temporal Tikhonov regularization in most realistic conditions considered. The limiting factor is the proper estimation of the arterial input function. CONCLUSION This study quantified the robustness of a spatio-temporal approach for dynamic susceptibility contrast-magnetic resonance imaging deconvolution via a new simulator. This simulator, now accessible online, is of wide applicability for the validation of any deconvolution algorithm. Magn Reson Med 78:1981-1990, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Mathilde Giacalone
- University of Lyon, INSA-Lyon, Université Claude Bernard Lyon 1, CNRS, Inserm, CREATIS UMR 5220, U1206, LYON, F69006, France
| | - Carole Frindel
- University of Lyon, INSA-Lyon, Université Claude Bernard Lyon 1, CNRS, Inserm, CREATIS UMR 5220, U1206, LYON, F69006, France
| | - Marc Robini
- University of Lyon, INSA-Lyon, Université Claude Bernard Lyon 1, CNRS, Inserm, CREATIS UMR 5220, U1206, LYON, F69006, France
| | - Frédéric Cervenansky
- University of Lyon, INSA-Lyon, Université Claude Bernard Lyon 1, CNRS, Inserm, CREATIS UMR 5220, U1206, LYON, F69006, France
| | - Emmanuel Grenier
- ENS-Lyon, UCB Lyon, Inria, NUMED, CNRS, UMPA UMR 5669, LYON, F69007, France
| | - David Rousseau
- University of Lyon, INSA-Lyon, Université Claude Bernard Lyon 1, CNRS, Inserm, CREATIS UMR 5220, U1206, LYON, F69006, France
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Heiss WD, Zaro Weber O. Validation of MRI Determination of the Penumbra by PET Measurements in Ischemic Stroke. J Nucl Med 2016; 58:187-193. [PMID: 27879370 DOI: 10.2967/jnumed.116.185975] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 11/10/2016] [Indexed: 11/16/2022] Open
Abstract
The concept of the ischemic penumbra was formulated on the basis of animal experiments showing functional impairment and electrophysiologic disturbances with decreasing flow to the brain below defined values (the threshold for function) and irreversible tissue damage with blood supply further decreased (the threshold for infarction). The perfusion range between these thresholds was termed the "penumbra," and restitution of flow above the functional threshold was able to reverse the deficits without permanent damage. In further experiments, the dependency of the development of irreversible lesions on the interaction of the severity and the duration of critically reduced blood flow was established, proving that the lower the flow, the shorter the time for efficient reperfusion. As a consequence, infarction develops from the core of ischemia to the areas of less severe hypoperfusion. The translation of this experimental concept as the basis for the efficient treatment of stroke requires noninvasive methods with which regional flow and energy metabolism can be repeatedly investigated to demonstrate penumbra tissue, which can benefit from therapeutic interventions. PET allows the quantification of regional cerebral blood flow, the regional oxygen extraction fraction, and the regional metabolic rate for oxygen. With these variables, clear definitions of irreversible tissue damage and of critically hypoperfused but potentially salvageable tissue (i.e., the penumbra) in stroke patients can be achieved. However, PET is a research tool, and its complex logistics limit clinical routine applications. Perfusion-weighted or diffusion-weighted MRI is a widely applicable clinical tool, and the "mismatch" between perfusion-weighted and diffusion-weighted abnormalities serves as an indicator of the penumbra. However, comparative studies of perfusion-weighted or diffusion-weighted MRI and PET have indicated overestimation of the core of irreversible infarction as well as of the penumbra by the MRI modalities. Some of these discrepancies can be explained by the nonselective application of relative perfusion thresholds, which might be improved by more complex analytic procedures. The heterogeneity of the MRI signatures used for the definition of the mismatch are also responsible for disappointing results in the application of perfusion-weighted or diffusion-weighted MRI to the selection of patients for clinical trials. As long as validation of the mismatch selection paradigm is lacking, the use of this paradigm as a surrogate marker of outcome is limited.
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Rodgers ZB, Detre JA, Wehrli FW. MRI-based methods for quantification of the cerebral metabolic rate of oxygen. J Cereb Blood Flow Metab 2016; 36:1165-85. [PMID: 27089912 PMCID: PMC4929705 DOI: 10.1177/0271678x16643090] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 02/22/2016] [Indexed: 11/16/2022]
Abstract
The brain depends almost entirely on oxidative metabolism to meet its significant energy requirements. As such, the cerebral metabolic rate of oxygen (CMRO2) represents a key measure of brain function. Quantification of CMRO2 has helped elucidate brain functional physiology and holds potential as a clinical tool for evaluating neurological disorders including stroke, brain tumors, Alzheimer's disease, and obstructive sleep apnea. In recent years, a variety of magnetic resonance imaging (MRI)-based CMRO2 quantification methods have emerged. Unlike positron emission tomography - the current "gold standard" for measurement and mapping of CMRO2 - MRI is non-invasive, relatively inexpensive, and ubiquitously available in modern medical centers. All MRI-based CMRO2 methods are based on modeling the effect of paramagnetic deoxyhemoglobin on the magnetic resonance signal. The various methods can be classified in terms of the MRI contrast mechanism used to quantify CMRO2: T2*, T2', T2, or magnetic susceptibility. This review article provides an overview of MRI-based CMRO2 quantification techniques. After a brief historical discussion motivating the need for improved CMRO2 methodology, current state-of-the-art MRI-based methods are critically appraised in terms of their respective tradeoffs between spatial resolution, temporal resolution, and robustness, all of critical importance given the spatially heterogeneous and temporally dynamic nature of brain energy requirements.
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Affiliation(s)
- Zachary B Rodgers
- University of Pennsylvania Medical Center, Philadelphia, PA, USA Laboratory for Structural, Physiologic, and Functional Imaging, Department of Radiology, Philadelphia, PA, USA
| | - John A Detre
- University of Pennsylvania Medical Center, Philadelphia, PA, USA Center for Functional Neuroimaging, Department of Neurology, Philadelphia, PA, USA
| | - Felix W Wehrli
- University of Pennsylvania Medical Center, Philadelphia, PA, USA
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Sim J, Jo A, Kang BM, Lee S, Bang OY, Heo C, Jhon GJ, Lee Y, Suh M. Cerebral Hemodynamics and Vascular Reactivity in Mild and Severe Ischemic Rodent Middle Cerebral Artery Occlusion Stroke Models. Exp Neurobiol 2016; 25:130-8. [PMID: 27358581 PMCID: PMC4923357 DOI: 10.5607/en.2016.25.3.130] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 06/15/2016] [Accepted: 06/16/2016] [Indexed: 01/20/2023] Open
Abstract
Ischemia can cause decreased cerebral neurovascular coupling, leading to a failure in the autoregulation of cerebral blood flow. This study aims to investigate the effect of varying degrees of ischemia on cerebral hemodynamic reactivity using in vivo real-time optical imaging. We utilized direct cortical stimulation to elicit hyper-excitable neuronal activation, which leads to induced hemodynamic changes in both the normal and middle cerebral artery occlusion (MCAO) ischemic stroke groups. Hemodynamic measurements from optical imaging accurately predict the severity of occlusion in mild and severe MCAO animals. There is neither an increase in cerebral blood volume nor in vessel reactivity in the ipsilateral hemisphere (I.H) of animals with severe MCAO. The pial artery in the contralateral hemisphere (C.H) of the severe MCAO group reacted more slowly than both hemispheres in the normal and mild MCAO groups. In addition, the arterial reactivity of the I.H in the mild MCAO animals was faster than the normal animals. Furthermore, artery reactivity is tightly correlated with histological and behavioral results in the MCAO ischemic group. Thus, in vivo optical imaging may offer a simple and useful tool to assess the degree of ischemia and to understand how cerebral hemodynamics and vascular reactivity are affected by ischemia.
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Affiliation(s)
- Jeongeun Sim
- Center for Neuroscience Imaging Research (CNIR), Institute for Basic Science (IBS), Suwon 16419, Korea
| | - Areum Jo
- Center for Neuroscience Imaging Research (CNIR), Institute for Basic Science (IBS), Suwon 16419, Korea
| | - Bok-Man Kang
- Department of Biomedical Engineering, Sungkyunkwan University, Suwon 16419, Korea
| | - Sohee Lee
- Center for Neuroscience Imaging Research (CNIR), Institute for Basic Science (IBS), Suwon 16419, Korea
| | - Oh Young Bang
- Department of Neurology, Neuroscience Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, Korea.; Department of Health Sciences and Technology, SAIHST, Sungkyunkwan University, Seoul 06351, Korea
| | - Chaejeong Heo
- Center for Neuroscience Imaging Research (CNIR), Institute for Basic Science (IBS), Suwon 16419, Korea
| | - Gil-Ja Jhon
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Youngmi Lee
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Minah Suh
- Center for Neuroscience Imaging Research (CNIR), Institute for Basic Science (IBS), Suwon 16419, Korea.; Department of Biomedical Engineering, Sungkyunkwan University, Suwon 16419, Korea.; Department of Health Sciences and Technology, SAIHST, Sungkyunkwan University, Seoul 06351, Korea
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Dejobert M, Cazals X, Annan M, Debiais S, Lauvin MA, Cottier JP. Susceptibility-Diffusion Mismatch in Hyperacute Stroke: Correlation with Perfusion-Diffusion Mismatch and Clinical Outcome. J Stroke Cerebrovasc Dis 2016; 25:1760-1766. [PMID: 27151417 DOI: 10.1016/j.jstrokecerebrovasdis.2016.02.025] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2015] [Revised: 01/18/2016] [Accepted: 02/19/2016] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND A prominent vein (PV) on susceptibility-weighted imaging (SWI) was recently proposed to be a marker of the penumbra. We aimed to compare the utility of SWI and perfusion-weighted imaging (PWI) sequences for the evaluation of the penumbra in hyperacute middle cerebral artery (MCA) stroke, and to determine whether SWI-DWI mismatch is a neuroimaging marker of clinical outcome. METHODS A total of 149 consecutive patients with MCA stroke were prospectively enrolled. Magnetic resonance imaging (MRI) was performed within 6 hours of the onset of stroke. The ASPECTS values on diffusion-weighted imaging (DWI), PWI (delayed mean transit time), and SWI (visualization of PVs) were calculated by 2 independent raters. Correlation between PWI-ASPECTS and SWI-ASPECTS was calculated with the Pearson coefficient. Reliability of the PV rating system was calculated by an intraclass correlation coefficient (ICC). Favorable outcome was defined as a modified Rankin Scale score of 0-2 at 3 months for the 88 patients who received thrombolytic therapy. RESULTS The ASPECTS-SWI and ASPECTS-PWI scores showed a good correlation (Pearson coefficient of .69, P <.001). The reproducibility between the findings of the junior and the senior radiologists was excellent with an ICC of .89 (confidence interval of 95% (IC95): .85-.92, P <.001). However, neither SWI-DWI mismatch nor PWI-SWI mismatch was associated with clinical outcome. CONCLUSION SWI and PWI were complementary but not commutable for the assessment of the penumbra. Susceptibility-diffusion mismatch was not found in this study to have predictive value for stroke outcome.
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Affiliation(s)
- Maelle Dejobert
- Department of Diagnostic and Interventional Neuroradiology, Bretonneau University Hospital, Tours, France.
| | - Xavier Cazals
- Department of Diagnostic and Interventional Neuroradiology, Bretonneau University Hospital, Tours, France
| | - Mariam Annan
- Department of Neurology, Bretonneau University Hospital, Tours, France
| | - Séverine Debiais
- Department of Neurology, Bretonneau University Hospital, Tours, France
| | - Marie-Agnes Lauvin
- Department of Diagnostic and Interventional Neuroradiology, Bretonneau University Hospital, Tours, France
| | - Jean-Philippe Cottier
- Department of Diagnostic and Interventional Neuroradiology, Bretonneau University Hospital, Tours, France
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Liu Z, Li Y. Cortical Cerebral Blood Flow, Oxygen Extraction Fraction, and Metabolic Rate in Patients with Middle Cerebral Artery Stenosis or Acute Stroke. AJNR Am J Neuroradiol 2015; 37:607-14. [PMID: 26680459 DOI: 10.3174/ajnr.a4624] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 08/09/2015] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE With the advances of magnetic resonance technology, the CBF, oxygen extraction fraction, and cerebral metabolic rate of oxygen can be measured in MRI. Our aim was to measure the CBF, oxygen extraction fraction, and cerebral metabolic rate of oxygen use in patients with different severities of middle cerebral artery stenosis or acute stroke by using the arterial spin-labeling and susceptibility-weighted imaging techniques. MATERIALS AND METHODS Fifty-seven patients with MCA stenosis or acute stroke were recruited and classified into 4 groups: mild MCA stenosis (group 1), severe MCA stenosis (group 2), occluded MCA (group 3), and acute stroke (group 4). Arterial spin-labeling and SWI sequences were used to acquire CBF, oxygen extraction fraction, and cerebral metabolic rate of oxygen. RESULTS The oxygen extraction fraction in hemispheres with mild MCA stenosis (group 1) was remarkably higher than that in the contralateral hemisphere. In addition, hemispheres with severe MCA stenosis (group 2) had significantly lower CBF and a significantly higher oxygen extraction fraction than the contralateral hemisphere. Hemispheres with occluded MCA (group 3) or acute stroke (group 4) had a significantly lower CBF and cerebral metabolic rate of oxygen and a significantly higher oxygen extraction fraction than the contralateral hemisphere. CONCLUSIONS The oxygen extraction fraction gradually increased in groups 1-3. When this offset a decrease in CBF, the cerebral metabolic rate of oxygen remained at a normal level. An occluded MCA led to reduction in both the CBF and cerebral metabolic rate of oxygen. Moreover, the oxygen extraction fraction and cerebral metabolic rate of oxygen significantly increased and decreased, respectively, in the occluded MCA region during acute stroke.
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Affiliation(s)
- Z Liu
- From the Department of Medical Imaging (Z.L.), First Hospital of Nanchang City, The Third Affiliated Hospital of Nanchang University, Nanchang City, China
| | - Y Li
- Department of Preventive Medicine (Y.L.), Heze Medical College, HeZe, Shandong, China
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Szigeti K, Horváth I, Veres DS, Martinecz B, Lénárt N, Kovács N, Bakcsa E, Márta A, Semjéni M, Máthé D, Dénes Á. A novel SPECT-based approach reveals early mechanisms of central and peripheral inflammation after cerebral ischemia. J Cereb Blood Flow Metab 2015; 35. [PMID: 26219594 PMCID: PMC4671129 DOI: 10.1038/jcbfm.2015.174] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Inflammation that develops in the brain and peripheral organs after stroke contributes profoundly to poor outcome of patients. However, mechanisms through which inflammation impacts on brain injury and overall outcome are improperly understood, in part because the earliest inflammatory events after brain injury are not revealed by current imaging tools. Here, we show that single-photon emission computed tomography (NanoSPECT/CT Plus) allows visualization of blood brain barrier (BBB) injury after experimental stroke well before changes can be detected with magnetic resonance imaging (MRI). Early 99mTc-DTPA (diethylene triamine pentaacetic acid) signal changes predict infarct development and systemic inflammation preceding experimental stroke leads to very early perfusion deficits and increased BBB injury within 2 hours after the onset of ischemia. Acute brain injury also leads to peripheral inflammation and immunosuppression, which contribute to poor outcome of stroke patients. The SPECT imaging revealed early (within 2 hours) changes in perfusion, barrier function and inflammation in the lungs and the gut after experimental stroke, with good predictive value for the development of histopathologic changes at later time points. Collectively, visualization of early inflammatory changes after stroke could open new translational research avenues to elucidate the interactions between central and peripheral inflammation and to evaluate in vivo 'multi-system' effects of putative anti-inflammatory treatments.
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Affiliation(s)
- Krisztián Szigeti
- Department of Biophysics and Radiation Biology, Semmelweis University, Budapest, Hungary
| | - Ildikó Horváth
- Department of Biophysics and Radiation Biology, Semmelweis University, Budapest, Hungary
| | - Dániel S Veres
- Department of Biophysics and Radiation Biology, Semmelweis University, Budapest, Hungary
| | - Bernadett Martinecz
- Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary
| | - Nikolett Lénárt
- Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary
| | - Noémi Kovács
- CROmed Translational Research Centers, Budapest, Hungary
| | - Erika Bakcsa
- Department of Biophysics and Radiation Biology, Semmelweis University, Budapest, Hungary
| | - Alexa Márta
- Department of Biophysics and Radiation Biology, Semmelweis University, Budapest, Hungary
| | | | - Domokos Máthé
- CROmed Translational Research Centers, Budapest, Hungary
| | - Ádám Dénes
- Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary
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Abstract
In acute stroke, the major factor for recovery is the early use of thrombolysis aimed at arterial recanalization and reperfusion of ischemic brain tissue. Subsequently, neurorehabilitative training critically improves clinical recovery due to augmention of postlesional plasticity. Neuroimaging and electrophysiology studies have revealed that the location and volume of the stroke lesion, the affection of nerve fiber tracts, as well as functional and structural changes in the perilesional tissue and in large-scale bihemispheric networks are relevant biomarkers of post-stroke recovery. However, associated disorders, such as mood disorders, epilepsy, and neurodegenerative diseases, may induce secondary cerebral changes or aggravate the functional deficits and, thereby, compromise the potential for recovery.
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Affiliation(s)
- Rüdiger J Seitz
- Department of Neurology, Centre of Neurology and Neuropsychiatry, LVR-Klinikum Düsseldorf, Heinrich-Heine-University Düsseldorf , Düsseldorf , Germany ; Biomedical Research Centre, Heinrich-Heine-University Düsseldorf , Düsseldorf , Germany ; Florey Institute of Neuroscience and Mental Health, University of Melbourne , Parkville, VIC , Australia
| | - Geoffrey A Donnan
- Florey Institute of Neuroscience and Mental Health, University of Melbourne , Parkville, VIC , Australia
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Prominent vessel sign on susceptibility-weighted imaging in acute stroke: prediction of infarct growth and clinical outcome. PLoS One 2015; 10:e0131118. [PMID: 26110628 PMCID: PMC4481350 DOI: 10.1371/journal.pone.0131118] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2015] [Accepted: 05/28/2015] [Indexed: 01/22/2023] Open
Abstract
Background and Purpose Predicting the risk of further infarct growth in stroke patients is critical to therapeutic decision making. We aimed to predict early infarct growth and clinical outcome from prominent vessel sign (PVS) identified on the first susceptibility-weighted image (SWI) after acute stroke. Materials and Methods Twenty-two patients with middle cerebral artery (MCA) infarction had diffusion-weighted imaging, SWI, MR angiography, and clinical evaluation using the National Institutes of Health Stroke Scale at 7–60 hours and 5–14 days after stroke onset. Late-stage clinical evaluation at 1 and 3 months used the modified Rankin Scale. The infarct area and growth were scored from 10 (none) to 0 (infarct or growth in all 10 zones) using the Alberta Stroke Program Early CT Score (ASPECTS) system. Results Infarct growth on the second MRI occurred in 13 of 15 patients with PVS on the first MRI and not in any patient without PVS (n=7; r=0.86, P<0.001). The extent of PVS was significantly correlated with infarct growth (r=0.82, P<0.001) and early-stage outcome (P=0.02). No between-group difference in late-stage clinical outcome was found. Conclusion PVS on the first SWI after acute MCA territory stroke is a useful predictor of early infarct growth. Extensive PVS within the large MCA territory is related to poor early-stage outcome and could be useful for clinical assessment of stroke.
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YAN GEN, DAI ZHUOZHI, XUAN YINGHUA, WU RENHUA. Early metabolic changes following ischemia onset in rats: an in vivo diffusion-weighted imaging and 1H-magnetic resonance spectroscopy study at 7.0 T. Mol Med Rep 2015; 11:4109-14. [PMID: 25634261 PMCID: PMC4394971 DOI: 10.3892/mmr.2015.3283] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Accepted: 01/02/2015] [Indexed: 02/05/2023] Open
Abstract
Despite improvements in imaging techniques, it remains challenging to quantitatively assess the time of ischemic onset of an acute ischemic stroke. It is crucial to evaluate the early signs of infarction, which are predictive of responses to recombinant tissue plasminogen activator within a treatment window of 4.5 h after stroke induction. The aim of the present study was to assess and quantify the onset time for hyperacute middle cerebral artery occlusion (MCAO) ischemic stroke by measuring the apparent diffusion coefficient (ADC) of diffusion‑weighted imaging (DWI) and 1H‑magnetic resonance spectroscopy (MRS) at 7.0 T. DWI, conventional T2‑weighted imaging (T2WI) and subsequent focal ADCs were employed to evaluate ischemic brain lesions in a rat model of MCAO (n=20) at different time‑points following a stroke. A quantitation of local changes in metabolite concentrations within the lesions was performed using MRS. Proton metabolites were quantified automatically using LCModel software. At 30 min after MCAO, intense signals were observed in the DWI spectra of all animals. No abnormal signal was observed within 3 h by T2WI. ADC images of the central area, peripheral striping and on the fringes of the infarction demonstrated a lower signal than that of the normal side. The ADC decreased significantly within 30 min after infarction, followed by a gradual elevation in volatility levels and then becoming relatively stable at a lower level 3 h later. MRS exhibited a consistent elevation of lactate and reduced N‑acetyl aspartic acid. Glutamate and taurine reached a maximum 2 h after MCAO and began to decrease 1 h later. In conclusion, the present study demonstrated that hyperacute ischemic stroke can be quantitatively detected with the application of ADC, DWI and MRS. These methods may also be used to quantitatively assess the ischemic onset time of a hyperacute stroke.
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Affiliation(s)
- GEN YAN
- Department of Radiology, Affiliated Hospital, Jiangnan University, Wuxi, Jiangsu 214062, P.R. China
- Department of Radiology, The Second Affiliated Hospital, Shantou University Medical College, Shantou, Guangdong 515041, P.R. China
| | - ZHUOZHI DAI
- Department of Radiology, The Second Affiliated Hospital, Shantou University Medical College, Shantou, Guangdong 515041, P.R. China
- Provincial Key Laboratory of Medical Molecular Imaging, Shantou, Guangdong 515041, P.R. China
| | - YINGHUA XUAN
- Department of Basic Medicine, Jiangnan University Medical School, Wuxi, Jiangsu 214122, P.R. China
| | - RENHUA WU
- Department of Radiology, The Second Affiliated Hospital, Shantou University Medical College, Shantou, Guangdong 515041, P.R. China
- Provincial Key Laboratory of Medical Molecular Imaging, Shantou, Guangdong 515041, P.R. China
- Correspondence to: Professor Renhua Wu, Department of Radiology, The Second Affiliated Hospital, Shantou University Medical College, 22 Dongxiabei Road, Shantou, Guangdong 515041, P.R. China, E-mail:
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Dehkharghani S, Bammer R, Straka M, Albin LS, Kass-Hout O, Allen JW, Rangaraju S, Qiu D, Winningham MJ, Nahab F. Performance and Predictive Value of a User-Independent Platform for CT Perfusion Analysis: Threshold-Derived Automated Systems Outperform Examiner-Driven Approaches in Outcome Prediction of Acute Ischemic Stroke. AJNR Am J Neuroradiol 2015; 36:1419-25. [PMID: 25999410 DOI: 10.3174/ajnr.a4363] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 01/20/2015] [Indexed: 01/07/2023]
Abstract
BACKGROUND AND PURPOSE Treatment strategies in acute ischemic stroke aim to curtail ischemic progression. Emerging paradigms propose patient subselection using imaging biomarkers derived from CT, CTA, and CT perfusion. We evaluated the performance of a fully-automated computational tool, hypothesizing enhancements compared with qualitative approaches. The correlation between imaging variables and clinical outcomes in a cohort of patients with acute ischemic stroke is reported. MATERIALS AND METHODS Sixty-two patients with acute ischemic stroke and MCA or ICA occlusion undergoing multidetector CT, CTA, and CTP were retrospectively evaluated. CTP was processed on a fully operator-independent platform (RApid processing of PerfusIon and Diffusion [RAPID]) computing automated core estimates based on relative cerebral blood flow and relative cerebral blood volume and hypoperfused tissue volumes at varying thresholds of time-to-maximum. Qualitative analysis was assigned by 2 independent reviewers for each variable, including CT-ASPECTS, CBV-ASPECTS, CBF-ASPECTS, CTA collateral score, and CTA clot burden score. Performance as predictors of favorable clinical outcome and final infarct volume was established for each variable. RESULTS Both RAPID core estimates, CT-ASPECTS, CBV-ASPECTS, and clot burden score correlated with favorable clinical outcome (P < .05); CBF-ASPECTS and collateral score were not significantly associated with favorable outcome, while hypoperfusion estimates were variably associated, depending on the selected time-to-maximum thresholds. Receiver operating characteristic analysis demonstrated disparities among tested variables, with RAPID core and hypoperfusion estimates outperforming all qualitative approaches (area under the curve, relative CBV = 0.86, relative CBF = 0.81; P < .001). CONCLUSIONS Qualitative approaches to acute ischemic stroke imaging are subject to limitations due to their subjective nature and lack of physiologic information. These findings support the benefits of high-speed automated analysis, outperforming conventional methodologies while limiting delays in clinical management.
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Affiliation(s)
- S Dehkharghani
- From the Departments of Radiology and Imaging Sciences (S.D., L.S.A., J.W.A., D.Q.)
| | - R Bammer
- Department of Radiology (R.B.), Stanford University Hospital, Stanford, California
| | - M Straka
- Institut für Radiologie und Nuklearmedizin (M.S.), Kantonsspital Winterthur, Winterthur, Switzerland
| | - L S Albin
- From the Departments of Radiology and Imaging Sciences (S.D., L.S.A., J.W.A., D.Q.)
| | - O Kass-Hout
- Department of Neurology (O.K.-H.), Catholic Health System, Buffalo, New York
| | - J W Allen
- From the Departments of Radiology and Imaging Sciences (S.D., L.S.A., J.W.A., D.Q.)
| | - S Rangaraju
- Neurology (S.R., M.J.W., F.N.), Emory University Hospital, Atlanta, Georgia
| | - D Qiu
- From the Departments of Radiology and Imaging Sciences (S.D., L.S.A., J.W.A., D.Q.)
| | - M J Winningham
- Neurology (S.R., M.J.W., F.N.), Emory University Hospital, Atlanta, Georgia
| | - F Nahab
- Neurology (S.R., M.J.W., F.N.), Emory University Hospital, Atlanta, Georgia
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Motta M, Ramadan A, Hillis AE, Gottesman RF, Leigh R. Diffusion-perfusion mismatch: an opportunity for improvement in cortical function. Front Neurol 2015; 5:280. [PMID: 25642208 PMCID: PMC4294157 DOI: 10.3389/fneur.2014.00280] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 12/09/2014] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVE There has been controversy over whether diffusion-perfusion mismatch provides a biomarker for the ischemic penumbra. In the context of clinical stroke trials, regions of the diffusion-perfusion mismatch that do not progress to infarct in the absence of reperfusion are considered to represent "benign oligemia." However, at least in some cases (particularly large vessel stenosis), some of this hypoperfused tissue may remain dysfunctional for a prolonged period without progressing to infarct and may recover function if eventually reperfused. We hypothesized that patients with persistent diffusion-perfusion mismatch using a hypoperfusion threshold of 4-5.9 s delay on time-to-peak (TTP) maps at least sometimes have persistent cognitive deficits relative to those who show some reperfusion of this hypoperfused tissue. METHODS We tested this hypothesis in 38 patients with acute ischemic stroke who had simple cognitive tests (naming or line cancelation) and MRI with diffusion and perfusion imaging within 24 h of onset and again within 10 days, most of whom had large vessel stenosis or occlusion. RESULTS A persistent perfusion deficit of 4-5.9 s delay in TTP on follow up MRI was associated with a persistent cognitive deficit at that time point (p < 0.001). When we evaluated only patients who did not have infarct growth (n = 14), persistent hypoperfusion (persistent mismatch) was associated with a lack of cognitive improvement compared with those who had reperfused. The initial volume of hypoperfusion did not correlate with the later infarct volume (progression to infarct), but change in volume of hypoperfusion correlated with change in cognitive performance (p = 0.0001). Moreover, multivariable regression showed that the change in volume of hypoperfused tissue of 4-5.9 s delay (p = 0.002), and change in volume of ischemic tissue on diffusion weighted imaging (p = 0.02) were independently associated with change in cognitive function. CONCLUSION Our results provide additional evidence that non-infarcted tissue with a TTP delay of 4-5.9 s may be associated with persistent deficits, even if it does not always result in imminent progression to infarct. This tissue may represent the occasional opportunity to intervene to improve function even days after onset of symptoms.
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Affiliation(s)
- Melissa Motta
- R Adams Shock Trauma Center, University of Maryland School of Medicine , Baltimore, MD , USA
| | - Amanda Ramadan
- Johns Hopkins University School of Medicine , Baltimore, MD , USA
| | - Argye E Hillis
- Department of Neurology, Johns Hopkins University School of Medicine , Baltimore, MD , USA
| | - Rebecca F Gottesman
- Department of Neurology, Johns Hopkins University School of Medicine , Baltimore, MD , USA
| | - Richard Leigh
- Department of Neurology, Johns Hopkins University School of Medicine , Baltimore, MD , USA
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Huang D, Li S, Dai Z, Shen Z, Yan G, Wu R. Novel gradient echo sequence‑based amide proton transfer magnetic resonance imaging in hyperacute cerebral infarction. Mol Med Rep 2015; 11:3279-84. [PMID: 25571956 PMCID: PMC4368135 DOI: 10.3892/mmr.2015.3165] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Accepted: 11/25/2014] [Indexed: 12/28/2022] Open
Abstract
In the progression of ischemia, pH is important and is essential in elucidating the association between metabolic disruption, lactate formation, acidosis and tissue damage. Chemical exchange-dependent saturation transfer (CEST) imaging can be used to detect tissue pH and, in particular, a specific form of CEST magnetic resonance imaging (MRI), termed amide proton transfer (APT) MRI, which is sensitive to pH and can detect ischemic lesions, even prior to diffusion abnormalities. The critical parameter governing the ability of CEST to detect pH is the sequence. In the present study, a novel strategy was used, based on the gradient echo sequence (GRE), which involved the insertion of a magnetization transfer pulse in each repetition time (TR) and minimizing the TR for in vivo APT imaging. The proposed GRE-APT MRI method was initially verified using a tissue-like pH phantom and optimized MRI parameters for APT imaging. In order to assess the range of acute cerebral infarction, rats (n=4) were subjected to middle cerebral artery occlusion (MCAO) and MRI scanning at 7 telsa (T). Hyperacute ischemic tissue damage was characterized using multiparametric imaging techniques, including diffusion, APT and T2-Weighted MRI. By using a magnetization transfer pulse and minimizing TR, GRE-APT provided high spatial resolution and a homogeneous signal, with clearly distinguished cerebral anatomy. The GRE-APT and diffusion MRI were significantly correlated with lactate content and the area of cerebral infarction in the APT and apparent diffusion coefficient (ADC) maps matched consistently during the hyperacute period. In addition, compared with the infarction area observed on the ADC MRI map, the APT map contained tissue, which had not yet been irreversibly damaged. Therefore, GRE-APT MRI waa able to detect ischemic lactic acidosis with sensitivity and spatiotemporal resolution, suggesting the potential use of pH MRI as a surrogate imaging marker of impaired tissue metabolism for the diagnosis and prognosis of hyperacute stroke.
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Affiliation(s)
- Dexiao Huang
- Department of Medical Imaging, The Second Affiliated Hospital, Medical College of Shantou University, Shantou, Guangdong 515041, P.R. China
| | - Shenkai Li
- Department of Medical Imaging, The Second Affiliated Hospital, Medical College of Shantou University, Shantou, Guangdong 515041, P.R. China
| | - Zhuozhi Dai
- Department of Medical Imaging, The Second Affiliated Hospital, Medical College of Shantou University, Shantou, Guangdong 515041, P.R. China
| | - Zhiwei Shen
- Department of Medical Imaging, The Second Affiliated Hospital, Medical College of Shantou University, Shantou, Guangdong 515041, P.R. China
| | - Gen Yan
- Department of Medical Imaging, The Second Affiliated Hospital, Medical College of Shantou University, Shantou, Guangdong 515041, P.R. China
| | - Renhua Wu
- Department of Medical Imaging, The Second Affiliated Hospital, Medical College of Shantou University, Shantou, Guangdong 515041, P.R. China
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Kim SM, Kwon SU, Kim JS, Kang DW. Early infarct growth predicts long-term clinical outcome in ischemic stroke. J Neurol Sci 2014; 347:205-9. [DOI: 10.1016/j.jns.2014.09.048] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Revised: 08/27/2014] [Accepted: 09/26/2014] [Indexed: 11/30/2022]
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Bauer S, Wagner M, Seiler A, Hattingen E, Deichmann R, Nöth U, Singer OC. Quantitative T2'-mapping in acute ischemic stroke. Stroke 2014; 45:3280-6. [PMID: 25278559 DOI: 10.1161/strokeaha.114.006530] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND AND PURPOSE Quantitative T2'-mapping detects regional changes in the relation of oxygenated and deoxygenated haemoglobine and might reflect areas with increased oxygen extraction. T2'-mapping in conjunction with an elaborate algorithm for motion correction was performed in patients with acute large-vessel stroke, and quantitative T2'-values were determined within the diffusion-weighted imaging lesion and perfusion-restricted tissue. METHODS Eleven patients (median age, 71 years) with acute middle cerebral or internal carotid artery occlusion underwent MRI before scheduled endovascular treatment. MR-examination included diffusion- and perfusion-weighted imaging and quantitative, motion-corrected mapping of T2'. Time-to-peak maps were thresholded for different degrees of perfusion delays (eg, ≥0 s, ≥ 2s) when compared with a reference time-to-peak value from healthy contralateral tissue. Mean T2'-values in areas with reduced apparent diffusion coefficient and in areas with impaired perfusion were compared with T2'-values in corresponding contralateral areas. RESULTS Median time between symptom onset and MRI was 238 minutes. T2'-values were significantly reduced within the apparent diffusion coefficient -lesion when compared with contralateral healthy tissue (83 ms [67, 97] versus 97 ms [91, 111]; P<0.003). In perfusion-restricted tissue, T2'-values were also significantly lower when compared with contralateral healthy tissue (ie, for time to peak, ≥0 s 93 ms [86, 102] versus 104 [90, 110]; P=0.008) but were significantly higher than within the apparent diffusion coefficient lesion. The severity of the perfusion impairment had no influence on median T2'-values. CONCLUSIONS Motion-corrected T2'-mapping reveals significant and gradually declining values from healthy to perfusion-disturbed to apparent diffusion coefficient-restricted tissue. Current T2'-mapping can differentiate between the ischemic core and the perfusion-impaired areas but not on its own between penumbral and oligemic tissue.
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Affiliation(s)
- Sonja Bauer
- From the Department of Neurology (S.B., A.S., O.C.S.), Institute for Neuroradiology (M.W., E.H.); and Brain Imaging Center (R.D., U.N.), University Hospital Frankfurt, Goethe University, Frankfurt, Germany
| | - Marlies Wagner
- From the Department of Neurology (S.B., A.S., O.C.S.), Institute for Neuroradiology (M.W., E.H.); and Brain Imaging Center (R.D., U.N.), University Hospital Frankfurt, Goethe University, Frankfurt, Germany
| | - Alexander Seiler
- From the Department of Neurology (S.B., A.S., O.C.S.), Institute for Neuroradiology (M.W., E.H.); and Brain Imaging Center (R.D., U.N.), University Hospital Frankfurt, Goethe University, Frankfurt, Germany
| | - Elke Hattingen
- From the Department of Neurology (S.B., A.S., O.C.S.), Institute for Neuroradiology (M.W., E.H.); and Brain Imaging Center (R.D., U.N.), University Hospital Frankfurt, Goethe University, Frankfurt, Germany
| | - Ralf Deichmann
- From the Department of Neurology (S.B., A.S., O.C.S.), Institute for Neuroradiology (M.W., E.H.); and Brain Imaging Center (R.D., U.N.), University Hospital Frankfurt, Goethe University, Frankfurt, Germany
| | - Ulrike Nöth
- From the Department of Neurology (S.B., A.S., O.C.S.), Institute for Neuroradiology (M.W., E.H.); and Brain Imaging Center (R.D., U.N.), University Hospital Frankfurt, Goethe University, Frankfurt, Germany
| | - Oliver C Singer
- From the Department of Neurology (S.B., A.S., O.C.S.), Institute for Neuroradiology (M.W., E.H.); and Brain Imaging Center (R.D., U.N.), University Hospital Frankfurt, Goethe University, Frankfurt, Germany.
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PET imaging in ischemic cerebrovascular disease: current status and future directions. Neurosci Bull 2014; 30:713-32. [PMID: 25138055 DOI: 10.1007/s12264-014-1463-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Accepted: 04/10/2014] [Indexed: 01/08/2023] Open
Abstract
Cerebrovascular diseases are caused by interruption or significant impairment of the blood supply to the brain, which leads to a cascade of metabolic and molecular alterations resulting in functional disturbance and morphological damage. These pathophysiological changes can be assessed by positron emission tomography (PET), which permits the regional measurement of physiological parameters and imaging of the distribution of molecular markers. PET has broadened our understanding of the flow and metabolic thresholds critical for the maintenance of brain function and morphology: in this application, PET has been essential in the transfer of the concept of the penumbra (tissue with perfusion below the functional threshold but above the threshold for the preservation of morphology) to clinical stroke and thereby has had great impact on developing treatment strategies. Radioligands for receptors can be used as early markers of irreversible neuronal damage and thereby can predict the size of the final infarcts; this is also important for decisions concerning invasive therapy in large ("malignant") infarctions. With PET investigations, the reserve capacity of blood supply to the brain can be tested in obstructive arteriosclerosis of the supplying arteries, and this again is essential for planning interventions. The effect of a stroke on the surrounding and contralateral primarily unaffected tissue can be investigated, and these results help to understand the symptoms caused by disturbances in functional networks. Chronic cerebrovascular disease causes vascular cognitive disorders, including vascular dementia. PET permits the detection of the metabolic disturbances responsible for cognitive impairment and dementia, and can differentiate vascular dementia from degenerative diseases. It may also help to understand the importance of neuroinflammation after stroke and its interaction with amyloid deposition in the development of dementia. Although the clinical application of PET investigations is limited, this technology had and still has a great impact on research into cerebrovascular diseases.
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Abstract
Neuroimaging has expanded beyond its traditional diagnostic role and become a critical tool in the evaluation and management of stroke. The objectives of imaging include prompt accurate diagnosis, treatment triage, prognosis prediction, and secondary preventative precautions. While capitalizing on the latest treatment options and expanding upon the "time is brain" doctrine, the ultimate goal of imaging is to maximize the number of treated patients and improve the outcome of one the most costly and morbid disease. A broad overview of comprehensive multimodal stroke imaging is presented here to affirm its utilization.
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Affiliation(s)
- Elizabeth Tong
- Neuroradiology Division, Department of Radiology, University of Virginia, Charlottesville, Virginia
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Altered resting-state FMRI signals in acute stroke patients with ischemic penumbra. PLoS One 2014; 9:e105117. [PMID: 25121486 PMCID: PMC4133354 DOI: 10.1371/journal.pone.0105117] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2014] [Accepted: 07/20/2014] [Indexed: 11/19/2022] Open
Abstract
Background Identifying the ischemic penumbra in acute stroke subjects is important for the clinical decision making process. The aim of this study was to use resting-state functional magnetic resonance singal (fMRI) to investigate the change in the amplitude of low-frequency fluctuations (ALFF) of these subjects in three different subsections of acute stroke regions: the infarct core tissue, the penumbra tissue, and the normal brain tissue. Another aim of this study was to test the feasilbility of consistently detecting the penumbra region of the brain through ALFF analysis. Methods Sixteen subjects with first-ever acute ischemic stroke were scanned within 27 hours of the onset of stroke using magnetic resonance imaging. The core of infarct regions and penumbra regions were determined by diffusion and perfusion-weighted imaging respectively. The ALFF were measured from resting-state blood oxygen level dependent (BOLD) fMRI scans. The averaged relative ALFF value of each regions were correlated with the time after the onset of stroke. Results Relative ALFF values were significantly different in the infarct core tissue, penumbra tissue and normal brain tissue. The locations of lesions in the ALFF maps did not match perfectly with diffusion and perfusion-weighted imagings; however, these maps provide a contrast that can be used to differentiate between penumbra brain tissue and normal brain tissue. Significant correlations between time after stroke onset and the relative ALFF values were present in the penumbra tissue but not in the infarct core and normal brain tissue. Conclusion Preliminary results from this study suggest that the ALFF reflects the underlying neurovascular activity and has a great potential to estimate the brain tissue viability after ischemia. Results also show that the ALFF may contribute to acute stroke imaging for thrombolytic or neuroprotective therapies.
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Meoded A, Poretti A, Benson JE, Tekes A, Huisman TA. Evaluation of the ischemic penumbra focusing on the venous drainage: The role of susceptibility weighted imaging (SWI) in pediatric ischemic cerebral stroke. J Neuroradiol 2014; 41:108-16. [DOI: 10.1016/j.neurad.2013.04.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Revised: 03/31/2013] [Accepted: 04/04/2013] [Indexed: 11/30/2022]
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Germuska M, Bulte DP. MRI measurement of oxygen extraction fraction, mean vessel size and cerebral blood volume using serial hyperoxia and hypercapnia. Neuroimage 2014; 92:132-42. [DOI: 10.1016/j.neuroimage.2014.02.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 01/06/2014] [Accepted: 02/01/2014] [Indexed: 01/11/2023] Open
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