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Otgonbaatar C, Lee JY, Jung KH, Hwang I, Yoo RE, Kang KM, Yun TJ, Choi SH, Kim JH, Sohn CH. Quantifying infarct core volume in ischemic stroke: What is the optimal threshold and parameters of computed tomography perfusion? J Stroke Cerebrovasc Dis 2023; 32:107062. [PMID: 36948076 DOI: 10.1016/j.jstrokecerebrovasdis.2023.107062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 02/03/2023] [Accepted: 02/20/2023] [Indexed: 03/22/2023] Open
Abstract
OBJECTIVE Although computed tomography perfusion (CTP) is used to select and guide decision-making processes in patients with acute ischemic stroke, there is no clear standardization of the optimal threshold to predict ischemic core volume accurately. The infarct core volume with a relative cerebral blood flow(rCBF) threshold of < 30% is commonly used. We aimed to assess the volumetric agreement of the infarct core volume with different CTP parameters and thresholds using CTP software (RAPID, VITREA) and the infarct volume on diffusion-weighted imaging (DWI), with a short interval time (within 60 min) between CTP and follow-up DWI. MATERIALS AND METHODS This retrospective study included 42 acute ischemic stroke patients with occlusion of the large artery in the anterior circulation between April 2017-November 2020. RAPID identified infarct core as tissue rCBF < 20-38%. VITREA defined the infarct core as cerebral blood volume (CBV) < 26-56%. Olea Sphere was used to measure infarct core volume on DWI. The CTP-infarct core volume with different thresholds of perfusion parameters (CBF threshold vs CBV threshold) were compared with DWI-infarct core volumes. RESULTS The median time between CTP and DWI was 37.5min. The commonly used threshold of CBV< 41% (4.3 mL) resulted in lower median infarct core volume difference compared to the commonly used thresholds of rCBF < 30% (8.2mL). On the other hand, the optimal thresholds of CBV < 26% (-1.0mL; 95% CI, -53.9 to 58.1 mL; 0.945) resulted in the lowest median infarct core volume difference, narrowest limits of agreement, and largest interclass correlation coefficient compared with the optimal thresholds of rCBF < 38% (4.9 mL; 95% CI, -36.4 to 62.9 mL; 0.939). CONCLUSION Our study found that the both optimal and commonly used thresholds of CBV provided a more accurate prediction of the infarct core volume in patients with AIS than rCBF.
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Affiliation(s)
| | - Ji Ye Lee
- Department of Radiology, Seoul National University Hospital, #101 Daehangno, Jongno-gu, Seoul 110-744, Republic of Korea
| | - Keun-Hwa Jung
- Department of Neurology, Seoul National University Hospital, Seoul, Republic of Korea
| | - Inpyeong Hwang
- Department of Radiology, Seoul National University Hospital, #101 Daehangno, Jongno-gu, Seoul 110-744, Republic of Korea
| | - Roh-Eul Yoo
- Department of Radiology, Seoul National University Hospital, #101 Daehangno, Jongno-gu, Seoul 110-744, Republic of Korea
| | - Koung Mi Kang
- Department of Radiology, Seoul National University Hospital, #101 Daehangno, Jongno-gu, Seoul 110-744, Republic of Korea
| | - Tae Jin Yun
- Department of Radiology, Seoul National University Hospital, #101 Daehangno, Jongno-gu, Seoul 110-744, Republic of Korea
| | - Seung Hong Choi
- Department of Radiology, College of Medicine, Seoul National University, Seoul, Republic of Korea; Department of Radiology, Seoul National University Hospital, #101 Daehangno, Jongno-gu, Seoul 110-744, Republic of Korea
| | - Ji-Hoon Kim
- Department of Radiology, College of Medicine, Seoul National University, Seoul, Republic of Korea; Department of Radiology, Seoul National University Hospital, #101 Daehangno, Jongno-gu, Seoul 110-744, Republic of Korea
| | - Chul-Ho Sohn
- Department of Radiology, College of Medicine, Seoul National University, Seoul, Republic of Korea; Department of Radiology, Seoul National University Hospital, #101 Daehangno, Jongno-gu, Seoul 110-744, Republic of Korea.
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Haacke EM, Chen Y, Utriainen D, Wu B, Wang Y, Xia S, He N, Zhang C, Wang X, Lagana MM, Luo Y, Fatemi A, Liu S, Gharabaghi S, Wu D, Sethi SK, Huang F, Sun T, Qu F, Yadav BK, Ma X, Bai Y, Wang M, Cheng J, Yan F. STrategically Acquired Gradient Echo (STAGE) imaging, part III: Technical advances and clinical applications of a rapid multi-contrast multi-parametric brain imaging method. Magn Reson Imaging 2019; 65:15-26. [PMID: 31629075 DOI: 10.1016/j.mri.2019.09.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2019] [Revised: 09/11/2019] [Accepted: 09/15/2019] [Indexed: 12/15/2022]
Abstract
One major thrust in radiology today is image standardization with a focus on rapidly acquired quantitative multi-contrast information. This is critical for multi-center trials, for the collection of big data and for the use of artificial intelligence in evaluating the data. Strategically acquired gradient echo (STAGE) imaging is one such method that can provide 8 qualitative and 7 quantitative pieces of information in 5 min or less at 3 T. STAGE provides qualitative images in the form of proton density weighted images, T1 weighted images, T2* weighted images and simulated double inversion recovery (DIR) images. STAGE also provides quantitative data in the form of proton spin density, T1, T2* and susceptibility maps as well as segmentation of white matter, gray matter and cerebrospinal fluid. STAGE uses vendors' product gradient echo sequences. It can be applied from 0.35 T to 7 T across all manufacturers producing similar results in contrast and quantification of the data. In this paper, we discuss the strengths and weaknesses of STAGE, demonstrate its contrast-to-noise (CNR) behavior relative to a large clinical data set and introduce a few new image contrasts derived from STAGE, including DIR images and a new concept referred to as true susceptibility weighted imaging (tSWI) linked to fluid attenuated inversion recovery (FLAIR) or tSWI-FLAIR for the evaluation of multiple sclerosis lesions. The robustness of STAGE T1 mapping was tested using the NIST/NIH phantom, while the reproducibility was tested by scanning a given individual ten times in one session and the same subject scanned once a week over a 12-week period. Assessment of the CNR for the enhanced T1W image (T1WE) showed a significantly better contrast between gray matter and white matter than conventional T1W images in both patients with Parkinson's disease and healthy controls. We also present some clinical cases using STAGE imaging in patients with stroke, metastasis, multiple sclerosis and a fetus with ventriculomegaly. Overall, STAGE is a comprehensive protocol that provides the clinician with numerous qualitative and quantitative images.
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Affiliation(s)
- E Mark Haacke
- Department of Radiology, Wayne State University School of Medicine, Detroit, MI, USA; The MRI Institute for Biomedical Research, Bingham Farms, MI, USA; Magnetic Resonance Innovations, Inc., Bingham Farms, MI, USA.
| | - Yongsheng Chen
- Department of Radiology, Wayne State University School of Medicine, Detroit, MI, USA; Department of Neurology, Wayne State University School of Medicine, Detroit, MI, USA
| | - David Utriainen
- The MRI Institute for Biomedical Research, Bingham Farms, MI, USA; Magnetic Resonance Innovations, Inc., Bingham Farms, MI, USA
| | - Bo Wu
- Magnetic Resonance Innovations, Inc., Bingham Farms, MI, USA
| | - Yu Wang
- Shanghai Key Laboratory of Magnetic Resonance, School of Physics and Electronic Science, East China Normal University, Shanghai, China; Neusoft Medical Systems Co., Ltd., Shanghai, China
| | - Shuang Xia
- Department of Radiology, Tianjin First Central Hospital, Tianjin, China
| | - Naying He
- Department of Radiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Chunyan Zhang
- Department of MRI, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Xiao Wang
- Department of MRI, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | | | - Yu Luo
- Department of Radiology, Translational Research Institute of Brain and Brain-Like Intelligence, Shanghai Fourth People's Hospital Affiliated to Tongji University School of Medicine, Shanghai, China
| | - Ali Fatemi
- Departments of Radiology and Radiation Oncology, University of Mississippi Medical Center, Jackson, MS, USA
| | - Saifeng Liu
- The MRI Institute for Biomedical Research, Bingham Farms, MI, USA
| | - Sara Gharabaghi
- Magnetic Resonance Innovations, Inc., Bingham Farms, MI, USA
| | - Dongmei Wu
- Shanghai Key Laboratory of Magnetic Resonance, School of Physics and Electronic Science, East China Normal University, Shanghai, China
| | - Sean K Sethi
- Department of Radiology, Wayne State University School of Medicine, Detroit, MI, USA; The MRI Institute for Biomedical Research, Bingham Farms, MI, USA; Magnetic Resonance Innovations, Inc., Bingham Farms, MI, USA
| | - Feng Huang
- Neusoft Medical Systems Co., Ltd., Shanghai, China
| | - Taotao Sun
- Department of Radiology, International Peace Maternity and Child Health Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Feifei Qu
- Department of Radiology, Wayne State University School of Medicine, Detroit, MI, USA
| | - Brijesh K Yadav
- Department of Radiology, Wayne State University School of Medicine, Detroit, MI, USA
| | - Xiaoyue Ma
- Department of Radiology, Henan Provincial People's Hospital, Zhengzhou, China; Department of Radiology, Zhengzhou University People's Hospital, Zhengzhou, China
| | - Yan Bai
- Department of Radiology, Henan Provincial People's Hospital, Zhengzhou, China; Department of Radiology, Zhengzhou University People's Hospital, Zhengzhou, China
| | - Meiyun Wang
- Department of Radiology, Henan Provincial People's Hospital, Zhengzhou, China; Department of Radiology, Zhengzhou University People's Hospital, Zhengzhou, China.
| | - Jingliang Cheng
- Department of MRI, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Fuhua Yan
- Department of Radiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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3
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van Beek EJR, Kuhl C, Anzai Y, Desmond P, Ehman RL, Gong Q, Gold G, Gulani V, Hall-Craggs M, Leiner T, Lim CCT, Pipe JG, Reeder S, Reinhold C, Smits M, Sodickson DK, Tempany C, Vargas HA, Wang M. Value of MRI in medicine: More than just another test? J Magn Reson Imaging 2018; 49:e14-e25. [PMID: 30145852 DOI: 10.1002/jmri.26211] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 05/16/2018] [Indexed: 02/06/2023] Open
Abstract
There is increasing scrutiny from healthcare organizations towards the utility and associated costs of imaging. MRI has traditionally been used as a high-end modality, and although shown extremely important for many types of clinical scenarios, it has been suggested as too expensive by some. This editorial will try and explain how value should be addressed and gives some insights and practical examples of how value of MRI can be increased. It requires a global effort to increase accessibility, value for money, and impact on patient management. We hope this editorial sheds some light and gives some indications of where the field may wish to address some of its research to proactively demonstrate the value of MRI. Level of Evidence: 5 Technical Efficacy: Stage 5 J. Magn. Reson. Imaging 2019;49:e14-e25.
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Affiliation(s)
| | - Christiane Kuhl
- Department of Diagnostic and Interventional Radiology, University of Aachen, Aachen, Germany
| | - Yoshimi Anzai
- Department of Radiology, University of Utah, Salt Lake City, Utah, USA
| | - Patricia Desmond
- Royal Melbourne Hospital, University of Melbourne, Melbourne, Australia
| | - Richard L Ehman
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA
| | - Qiyong Gong
- Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Garry Gold
- Department of Radiology, Engineering and Orthopaedic Surgery, Stanford University, Stanford, California, USA
| | - Vikas Gulani
- Departments of Radiology, Urology and Biomedical Imaging, Case Western Reserve University, University Hospitals of Cleveland, Cleveland, Ohio, USA
| | - Margaret Hall-Craggs
- Department of Medical Imaging and Radiology, University College Hospital NHS Trust, London, UK
| | - Tim Leiner
- Department of Radiology and Nuclear Medicine, University Medical Centre, Utrecht, The Netherlands
| | - C C Tschoyoson Lim
- Department of Neuroradiology, National Neuroscience Institute and Duke NUS Medical School, Singapore, Singapore
| | - James G Pipe
- Department of Imaging Research, Barrow Neurological Institute, Phoenix, Arizona, USA
| | - Scott Reeder
- Departments of Radiology, Medical Physics, Biomedical Engineering, Medicine and Emergency Medicine, University of Madison, Madison, Wisconsin, USA
| | - Caroline Reinhold
- Department of Radiology, McGill University Health Center, Montreal, Canada
| | - Marion Smits
- Department of Radiology and Nuclear Medicine, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Daniel K Sodickson
- Department of Radiology, New York University Langone Health, New York, New York, USA
| | - Clare Tempany
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - H Alberto Vargas
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, New York, USA
| | - Meiyun Wang
- Department of Radiology, Henan Provincial People's Hospital, Zhengzhou, Henan, China
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Shahid H, Sebastian R, Tippett DC, Saxena S, Wright A, Hanayik T, Breining B, Bonilha L, Fridriksson J, Rorden C, Hillis AE. Regional Brain Dysfunction Associated with Semantic Errors in Comprehension. Semin Speech Lang 2018; 39:79-86. [PMID: 29359307 DOI: 10.1055/s-0037-1608858] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Here we illustrate how investigation of individuals acutely after stroke, before structure/function reorganization through recovery or rehabilitation, can be helpful in answering questions about the role of specific brain regions in language functions. Although there is converging evidence from a variety of sources that the left posterior-superior temporal gyrus plays some role in spoken word comprehension, its precise role in this function has not been established. We hypothesized that this region is essential for distinguishing between semantically related words, because it is critical for linking the spoken word to the complete semantic representation. We tested this hypothesis in 127 individuals with 48 hours of acute ischemic stroke, before the opportunity for reorganization or recovery. We identified tissue dysfunction (acute infarct and/or hypoperfusion) in gray and white matter parcels of the left hemisphere, and we evaluated the association between rate of semantic errors in a word-picture verification tasks and extent of tissue dysfunction in each region. We found that after correcting for lesion volume and multiple comparisons, the rate of semantic errors correlated with the extent of tissue dysfunction in left posterior-superior temporal gyrus and retrolenticular white matter.
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Affiliation(s)
- Hinna Shahid
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Rajani Sebastian
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Donna C Tippett
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland.,Department of Physical Medicine and Rehabilitation, Johns Hopkins University School of Medicine, Baltimore, Maryland.,Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Sadhvi Saxena
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Amy Wright
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | | | - Bonnie Breining
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Leonardo Bonilha
- Department of Neurology, Medical University of South Carolina, Columbia, South Carolina
| | | | - Chris Rorden
- University of South Carolina, Columbia, South Carolina
| | - Argye E Hillis
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland.,Department of Physical Medicine and Rehabilitation, Johns Hopkins University School of Medicine, Baltimore, Maryland.,Department of Cognitive Science, Johns Hopkins University, Baltimore, Maryland
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5
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Kurz MW, Advani R, Behzadi GN, Eldøen G, Farbu E, Kurz KD. Wake-up stroke-Amendable for thrombolysis-like stroke with known onset time? Acta Neurol Scand 2017; 136:4-10. [PMID: 27641907 DOI: 10.1111/ane.12686] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/29/2016] [Indexed: 11/26/2022]
Abstract
Patients suffering an acute ischemic stroke can be treated with intravenous thrombolysis in the absence of contraindications. A known onset time is a prerequisite as treatment, according to guidelines, has to be started within 4.5 hours. In patients awakening with a stroke, the last time they were seen without a neurological deficit is assumed to be the time of onset. Thus, despite of lack of contraindications on initial brain imaging, these patients are largely excluded from therapy. This review discusses the underlying pathophysiological, clinical, and radiological evidence surrounding wake-up stroke and its consequences for making treatment decisions.
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Affiliation(s)
- M. W. Kurz
- Department of Neurology; Stavanger University Hospital; Stavanger Norway
- Neuroscience Research Group; Stavanger University Hospital; Stavanger Norway
| | - R. Advani
- Department of Neurology; Stavanger University Hospital; Stavanger Norway
- Neuroscience Research Group; Stavanger University Hospital; Stavanger Norway
| | - G. N. Behzadi
- Department of Radiology; Stavanger University Hospital; Stavanger Norway
- Radiological Research Group; Stavanger University Hospital; Stavanger Norway
| | - G. Eldøen
- Department of Neurology; Molde County Hospital; Molde Norway
| | - E. Farbu
- Department of Neurology; Stavanger University Hospital; Stavanger Norway
- Neuroscience Research Group; Stavanger University Hospital; Stavanger Norway
- Department of Clinical Medicine; Haukeland University Hospital; Bergen Norway
| | - K. D. Kurz
- Department of Radiology; Stavanger University Hospital; Stavanger Norway
- Radiological Research Group; Stavanger University Hospital; Stavanger Norway
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6
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Benzakoun J, Maïer B, Calvet D, Edjlali M, Turc G, Lion S, Legrand L, Ben Hassen W, Naggara O, Meder J, Mas J, Oppenheim C. Can a 15-sec FLAIR replace conventional FLAIR sequence in stroke MR protocols? J Neuroradiol 2017; 44:192-197. [DOI: 10.1016/j.neurad.2016.11.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 10/10/2016] [Accepted: 11/21/2016] [Indexed: 10/20/2022]
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7
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Comprehensive imaging of stroke – Looking for the gold standard. Neurol Neurochir Pol 2016; 50:241-50. [DOI: 10.1016/j.pjnns.2016.04.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Revised: 04/12/2016] [Accepted: 04/18/2016] [Indexed: 11/20/2022]
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Hu LB, Hong N, Zhu WZ. Quantitative Measurement of Cerebral Perfusion with Intravoxel Incoherent Motion in Acute Ischemia Stroke: Initial Clinical Experience. Chin Med J (Engl) 2016; 128:2565-9. [PMID: 26415791 PMCID: PMC4736872 DOI: 10.4103/0366-6999.166033] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Background: Intravoxel incoherent motion (IVIM) has the potential to provide both diffusion and perfusion information without an exogenous contrast agent, its application for the brain is promising, however, feasibility studies on this are relatively scarce. The aim of this study is to assess the feasibility of IVIM perfusion in patients with acute ischemic stroke (AIS). Methods: Patients with suspected AIS were examined by magnetic resonance imaging within 24 h of symptom onset. Fifteen patients (mean age was 68.7 ± 8.0 years) who underwent arterial spin labeling (ASL) and diffusion-weighted imaging (DWI) were identified as having AIS with ischemic penumbra were enrolled, where ischemic penumbra referred to the mismatch areas of ASL and DWI. Eleven different b-values were applied in the biexponential model. Regions of interest were selected in ischemic penumbras and contralateral normal brain regions. Fast apparent diffusion coefficients (ADCs) and ASL cerebral blood flow (CBF) were measured. The paired t-test was applied to compare ASL CBF, fast ADC, and slow ADC measurements between ischemic penumbras and contralateral normal brain regions. Linear regression and Pearson's correlation were used to evaluate the correlations among quantitative results. Results: The fast ADCs and ASL CBFs of ischemic penumbras were significantly lower than those of the contralateral normal brain regions (1.93 ± 0.78 μm2/ms vs. 3.97 ± 2.49 μm2/ms, P = 0.007; 13.5 ± 4.5 ml·100 g-1·min-1 vs. 29.1 ± 12.7 ml·100 g-1·min-1, P < 0.001, respectively). No significant difference was observed in slow ADCs between ischemic penumbras and contralateral normal brain regions (0.203 ± 0.090 μm2/ms vs. 0.198 ± 0.100 αμm2/ms, P = 0.451). Compared with contralateral normal brain regions, both CBFs and fast ADCs decreased in ischemic penumbras while slow ADCs remained the same. A significant correlation was detected between fast ADCs and ASL CBFs (r = 0.416, P < 0.05). No statistically significant correlation was observed between ASL CBFs and slow ADCs, or between fast ADCs and slow ADCs (r = 0.111, P = 0.558; r = 0.200, P = 0.289, respectively). Conclusions: The decrease in cerebral blood perfusion primarily results in the decrease in fast ADC in ischemic penumbras; therefore, fast ADC can reflect the perfusion situation in cerebral tissues.
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Affiliation(s)
| | - Nan Hong
- Department of Radiology, Peking University People's Hospital, Beijing 100044, China
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9
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Srinivasan A, Goyal M, Lum C, Nguyen T, Miller W. Processing and Interpretation Times of CT Angiogram and CT Perfusion in Stroke. Can J Neurol Sci 2014; 32:483-6. [PMID: 16408579 DOI: 10.1017/s0317167100004480] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
ABSTRACT:Objective:To determine the mean time for acquiring computed tomogram perfusion (CTP) and CT angiogram (CTA) images in acute stroke. To determine and compare processing and interpretation times amongst three groups of radiologists with varying degree of expertise: two radiology residents (Group I), two neuroradiology fellows (Group II) and four consultant neuroradiologists (Group III).Methods:The mean time of acquisition of CTA and CTP studies was calculated among ten patients presenting with acute stroke. All readers had to process the CTA and CTP images, interpret them (for presence or absence of thrombus and penumbra) and save them on the GE Advantage Windows workstation. The mean time for processing and interpreting these studies was calculated.Results:The mean time for acquisition of CTA and CTP studies in the ten patients was 14.6 ± 5.9 minutes. The time taken for CTA processing and interpretation in Groups I, II and III was 2.3 ± 1.3 min, 1.6 ± 0.4 min and 1.5 ± 0.7 min respectively. The time required for CTP processing and interpretation by the same groups was 5.2 ± 1.7 min, 4.5 ± 1.5 min and 4.1 ± 1.1 min respectively. There was a statistically significant difference of means between Groups I and III in the CTA and CTP processing and interpretation times (p=0.02, p=0.01 respectively) but no statistical difference between Groups I and II (p=0.15, p=0.22 respectively) or Groups II and III (p=0.31, p=0.30 respectively).Conclusion:The CTA and CTP studies can be performed, processed and interpreted quickly in acute stroke.
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Affiliation(s)
- Ashok Srinivasan
- Department of Diagnostic Imaging, The Ottawa Hospital, Ottawa, Canada
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10
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Mehta BP, Leslie-Mazwi TM, Simonsen CZ, Rabinov JD, Hirsch JA, Gupta R, Yoo AJ. ADAPT FAST Study: third-generation stroke thrombectomy devices place renewed focus on the elusive relationship between revascularization and good outcomes. J Neurointerv Surg 2014; 8:e21-3. [DOI: 10.1136/neurintsurg-2014-011507] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/09/2014] [Indexed: 11/03/2022]
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11
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Mair G, Wardlaw JM. Imaging of acute stroke prior to treatment: current practice and evolving techniques. Br J Radiol 2014; 87:20140216. [PMID: 24936980 DOI: 10.1259/bjr.20140216] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Standard imaging in acute stroke is undertaken with the aim of diagnosing the underlying cause and excluding stroke mimics. In the presence of ischaemic stroke, imaging is also needed to assess patient suitability for treatment with intravenous thrombolysis. Non-contrast CT is predominantly used, but MRI can also exclude any contraindications to thrombolysis treatment. Advanced stroke imaging such as CT and MR angiography and perfusion imaging are increasingly used in an acute setting. In this review, we discuss the evidence for the application of these advanced techniques in the imaging of acute stroke.
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Affiliation(s)
- G Mair
- Brain Research Imaging Centre, Division of Neuroimaging Sciences, Centre for Clinical Brain Science, University of Edinburgh, Western General Hospital, Edinburgh, UK
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12
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Schumacher HC, Gupta R, Higashida RT, Meyers PM. Advances in revascularization for acute ischemic stroke treatment. Expert Rev Neurother 2014; 5:189-201. [PMID: 15853489 DOI: 10.1586/14737175.5.2.189] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Intravenous thrombolysis with recombinant tissue plasminogen activator is the established treatment for acute ischemic stroke patients presenting within 3 h after stroke onset. In a significant number of patients, however, intravenous thrombolysis with recombinant tissue plasminogen activator remains ineffective. New thrombolytic agents, such as reteplase, tenecteplase or desmoteplase, offer pharmacokinetic and dynamic advantages over recombinant tissue plasminogen activator and have been or are currently being tested for safety and efficacy in clinical trials. Endovascular revascularization is an evolving treatment option enabling mechanical clot disruption or extraction in combination with thrombolysis. Several new endovascular devices have been successfully tested for safety in acute ischemic stroke patients and are now being tested for efficacy in larger clinical trials. Continued innovation and refinement of endovascular technology and techniques is expected to increase technical success with a minimal procedure-related morbidity in the treatment of acute ischemic stroke.
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Affiliation(s)
- H Christian Schumacher
- Doris and Stanley Tananbaum Stroke Center, Neurological Institute, New York-Presbyterian Hospital, College of Physicians & Surgeons, Columbia University, 710 West 168th Street, Box 163, NY 10032, USA.
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13
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Burke JF, Gelb DJ, Quint DJ, Morgenstern LB, Kerber KA. The impact of MRI on stroke management and outcomes: a systematic review. J Eval Clin Pract 2013; 19:987-93. [PMID: 23173645 DOI: 10.1111/jep.12011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/03/2012] [Indexed: 10/27/2022]
Abstract
RATIONALE, AIMS AND OBJECTIVES Magnetic resonance imaging (MRI) is widely used in stroke evaluation and is superior to computed tomography for the detection of acute ischaemia. We sought to evaluate the evidence that conventional MRI influences doctor management or patient outcomes in routine care. METHODS We systematically searched PubMED, EMBASE and proceedings of the International Stroke Conference. Studies were included if they included patients presenting with possible stroke syndromes and they reported MRI results and resulting changes in management or outcome. Multiple reviewers determined inclusion/exclusion for each study, abstracted study characteristics and assessed study quality. RESULTS Of 1813 articles screened, nine studies met inclusion criteria. None were randomized controlled trials, cohort studies or case-control studies. We found little evidence that MRI affects outcomes - one single-centre case series presented three patients. The remaining articles were studies of diagnostic tests or vignette-based studies that described changes in doctor management attributed to MRI. In the studies that suggested MRI influenced management, it did so in two ways. First, MRI distinguished stroke from mimics (e.g. brain tumours), thus enabling more appropriate selection of therapies. Second, even when MRI confirmed a suspected stroke diagnosis, it sometimes provided information (on stroke mechanism, localization, timing or pathophysiology) that influenced management. CONCLUSIONS The impact of MRI on management and outcomes in stroke patients has been inadequately studied. Further research is needed to understand how MRI may productively affect stroke management and outcomes.
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Affiliation(s)
- James F Burke
- Department of Veterans Affairs, VA Center for Clinical Management and Research, Ann Arbor VA Healthcare System, Ann Arbor, Michigan, USA; Robert Wood Johnson Clinical Scholars Program, University of Michigan, Ann Arbor, Michigan, USA; Department of Neurology, University of Michigan, Ann Arbor, Michigan, USA
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14
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Wang L, Lin Z, Shao B, Zhuge Q, Jin K. Therapeutic applications of bone marrow-derived stem cells in ischemic stroke. Neurol Res 2013; 35:470-8. [PMID: 23595085 DOI: 10.1179/1743132813y.0000000210] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Liuqing Wang
- Department of Neurology the First Affiliated Hospital, Wenzhou Medical College, China
| | - Zhenzhen Lin
- Department of Neurology the First Affiliated Hospital, Wenzhou Medical College, China
| | - Bei Shao
- Department of Neurology the First Affiliated Hospital, Wenzhou Medical College, China
| | - Qichuan Zhuge
- Zhejiang Provincial Key Laboratory of Aging and Neurological Disorder Researchthe First Affiliated Hospital, Wenzhou Medical College, China
| | - Kunlin Jin
- Zhejiang Provincial Key Laboratory of Aging and Neurological Disorder Researchthe First Affiliated Hospital, Wenzhou Medical College, China
- Department of Pharmacology and NeuroscienceInstitute for Aging and Alzheimer’s Disease Research, University of North Texas Health Science Center at Fort Worth, USA
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Paolini S, Burdine J, Verenes M, Webster J, Faber T, Graham CB, Sen S. Rapid Short MRI Sequence Useful in Eliminating Stroke Mimics Among Acute Stroke Patients Considered for Intravenous Thrombolysis. JOURNAL OF NEUROLOGICAL DISORDERS 2013; 1:137. [PMID: 24839612 PMCID: PMC4021859 DOI: 10.4172/2329-6895.1000137] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Acute stroke teams are challenged by IV-tPA decision making in patients with acute neurological symptoms when the diagnosis is unclear. The purpose of this study was to evaluate the ability of the rapid Brain Attack Team (BAT) MRI in selecting patients for IV-tPA administration who present acutely to the emergency room with stroke-like symptoms and an unclear diagnosis. METHODS Consecutive patients were identified who presented within 4.5 hours of onset of stroke-like symptoms and considered for treatment with IV-tPA. When the diagnosis was not clear, a 9-minute BAT MRI was obtained. Stroke risk factors and NIH stroke scale obtained on presentation were compared between patients in whom BAT MRI was obtained and those in whom BAT MRI was not obtained. Similarly, comparisons were made between patients in whom BAT MRI detected abnormalities and those in whom BAT MRI did not detect abnormalities. BAT MRIs were analyzed to determine if radiological findings impacted clinical management and discharge diagnosis. RESULTS In a 30-month period, 432 patients presenting with acute stroke-like symptoms were identified. Of these patients, 82 received BAT MRI. Patients receiving BAT MRI were younger, more likely to be smokers, and less likely to be selected for IV-tPA administration compared to those in whom a more definitive diagnosis of stroke precluded a BAT MRI. Of the 82 BAT MRIs, 25 were read as positive for acute ischemia. The patients with acute ischemia on BAT MRI were older, more likely to be males, have a history of hypercholesterolemia and atrial fibrillation, and more likely to be selected for IV-tPA administration compared to those with a negative BAT MRI. Of the 57 BAT MRIs read as negative for acute ischemia or hemorrhage, discharge diagnoses included TIA, MRI negative stroke, conversion/functional disorder, and multiple other illnesses. CONCLUSION In patients with acute stroke-like symptoms, BAT MRI may be used to confirm acute ischemic stroke, exclude stroke mimics, and assess candidacy for IV-tPA.
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Affiliation(s)
- Stephanie Paolini
- Department of Neurology, University of South Carolina School of Medicine, Columbia, South Carolina, USA
| | - Joselyn Burdine
- Department of Neurology, University of South Carolina School of Medicine, Columbia, South Carolina, USA
| | - Michael Verenes
- Department of Neurology, University of South Carolina School of Medicine, Columbia, South Carolina, USA
| | - James Webster
- Department of Neurology, University of South Carolina School of Medicine, Columbia, South Carolina, USA
| | - Theodore Faber
- Department of Neurology, University of South Carolina School of Medicine, Columbia, South Carolina, USA
| | - Cole Blease Graham
- Department of Neurology, University of South Carolina School of Medicine, Columbia, South Carolina, USA
| | - Souvik Sen
- Department of Neurology, University of South Carolina School of Medicine, Columbia, South Carolina, USA
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Khedr SA, Kassem HM, Hazzou AM, Awad E, Fouad MM. MRI diffusion-weighted imaging in intracranial hemorrhage (ICH). THE EGYPTIAN JOURNAL OF RADIOLOGY AND NUCLEAR MEDICINE 2013. [DOI: 10.1016/j.ejrnm.2013.04.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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Abstract
Traditionally non-contrast CT has been considered the first choice imaging modality for acute stroke. Acute ischemic stroke patients presenting to the hospital within 3-hours from symptom onset and without any visible hemorrhages or large lesions on CT images are considered optimum reperfusion therapy candidates. However, non-contrast CT alone has been unable to identify best reperfusion therapy candidates outside this window. New advanced imaging techniques are now being used successfully for this purpose. Non-invasive CT or MR angiography images can be obtained during initial imaging evaluation for identification and characterization of vascular lesions, including occlusions, aneurysms, and malformations. Either CT-based perfusion imaging or MRI-based diffusion and perfusion imaging performed immediately upon arrival of a patient to the hospital helps estimate the extent of fixed core and penumbra in ischemic lesions. Patients having occlusive lesions with small fixed cores and large penumbra are preferred reperfusion therapy candidates.
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Abstract
The most important service that imaging provides to patients with ischemic stroke is to rapidly identify those patients who are most likely to benefit from immediate treatment. This group includes patients who have severe neurological symptoms due to an occlusion of a major artery, and who are candidates for recanalization using intravenous thrombolysis or intra-arterial intervention to remove the occlusion. Outcomes for these patients are determined by symptom severity, the artery that is occluded, the size of the infarct at the time of presentation, and the effect of treatment. MRI provides key physiological information through MR angiography and diffusion MRI that has been proven to be of high clinical value in identify patients who are in need of immediate treatment. Perfusion MRI provides information about the ischemic penumbra, but its clinical value is unproven. In current clinical practice, the time since stroke onset is dominant over physiologic information provided by MRI in treatment decisions. This will change only when clinical trials prove that stroke physiology as revealed by MRI is superior to time from stroke onset in promoting good clinical outcomes.
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Chen F, Ni YC. Magnetic resonance diffusion-perfusion mismatch in acute ischemic stroke: An update. World J Radiol 2012; 4:63-74. [PMID: 22468186 PMCID: PMC3314930 DOI: 10.4329/wjr.v4.i3.63] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Revised: 02/22/2012] [Accepted: 03/01/2012] [Indexed: 02/06/2023] Open
Abstract
The concept of magnetic resonance perfusion-diffusion mismatch (PDM) provides a practical and approximate measure of the tissue at risk and has been increasingly applied for the evaluation of hyperacute and acute stroke in animals and patients. Recent studies demonstrated that PDM does not optimally define the ischemic penumbra; because early abnormality on diffusion-weighted imaging overestimates the infarct core by including part of the penumbra, and the abnormality on perfusion weighted imaging overestimates the penumbra by including regions of benign oligemia. To overcome these limitations, many efforts have been made to optimize conventional PDM. Various alternatives beyond the PDM concept are under investigation in order to better define the penumbra. The PDM theory has been applied in ischemic stroke for at least three purposes: to be used as a practical selection tool for stroke treatment; to test the hypothesis that patients with PDM pattern will benefit from treatment, while those without mismatch pattern will not; to be a surrogate measure for stroke outcome. The main patterns of PDM and its relation with clinical outcomes were also briefly reviewed. The conclusion was that patients with PDM documented more reperfusion, reduced infarct growth and better clinical outcomes compared to patients without PDM, but it was not yet clear that thrombolytic therapy is beneficial when patients were selected on PDM. Studies based on a larger cohort are currently under investigation to further validate the PDM hypothesis.
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Abstract
Computed tomographic perfusion (CTP) imaging is an advanced modality that provides important information about capillary-level hemodynamics of the brain parenchyma. CTP can aid in diagnosis, management, and prognosis of acute stroke patients by clarifying acute cerebral physiology and hemodynamic status, including distinguishing severely hypoperfused but potentially salvageable tissue from both tissue likely to be irreversibly infarcted ("core") and hypoperfused but metabolically stable tissue ("benign oligemia"). A qualitative estimate of the presence and degree of ischemia is typically required for guiding clinical management. Radiation dose issues with CTP imaging, a topic of much current concern, are also addressed in this review.
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Affiliation(s)
- Angelos A Konstas
- Department of Radiology, Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114, USA.
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Yoo AJ, Pulli B, Gonzalez RG. Imaging-based treatment selection for intravenous and intra-arterial stroke therapies: a comprehensive review. Expert Rev Cardiovasc Ther 2011; 9:857-76. [PMID: 21809968 DOI: 10.1586/erc.11.56] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Reperfusion therapy is the only approved treatment for acute ischemic stroke. The current approach to patient selection is primarily based on the time from stroke symptom onset. However, this algorithm sharply restricts the eligible patient population, and neglects large variations in collateral circulation that ultimately determine the therapeutic time window in individual patients. Time alone is unlikely to remain the dominant parameter. Alternative approaches to patient selection involve advanced neuroimaging methods including MRI diffusion-weighted imaging, magnetic resonance and computed tomography perfusion imaging and noninvasive angiography that provide potentially valuable information regarding the state of the brain parenchyma and the neurovasculature. These techniques have now been used extensively, and there is emerging evidence on how specific imaging data may result in improved clinical outcomes. This article will review the major studies that have investigated the role of imaging in patient selection for both intravenous and intra-arterial therapies.
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Affiliation(s)
- Albert J Yoo
- Massachusetts General Hospital, 55 Fruit Street, Gray 241, Boston, MA 02114, USA.
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Peuser J, Belhaj-Saif A, Hamadjida A, Schmidlin E, Gindrat AD, Völker AC, Zakharov P, Hoogewoud HM, Rouiller EM, Scheffold F. Follow-up of cortical activity and structure after lesion with laser speckle imaging and magnetic resonance imaging in nonhuman primates. JOURNAL OF BIOMEDICAL OPTICS 2011; 16:096011. [PMID: 21950925 DOI: 10.1117/1.3625287] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The nonhuman primate model is suitable to study mechanisms of functional recovery following lesion of the cerebral cortex (motor cortex), on which therapeutic strategies can be tested. To interpret behavioral data (time course and extent of functional recovery), it is crucial to monitor the properties of the experimental cortical lesion, induced by infusion of the excitotoxin ibotenic acid. In two adult macaque monkeys, ibotenic acid infusions produced a restricted, permanent lesion of the motor cortex. In one monkey, the lesion was monitored over 3.5 weeks, combining laser speckle imaging (LSI) as metabolic readout (cerebral blood flow) and anatomical assessment with magnetic resonance imaging (T2-weighted MRI). The cerebral blood flow, measured online during subsequent injections of the ibotenic acid in the motor cortex, exhibited a dramatic increase, still present after one week, in parallel to a MRI hypersignal. After 3.5 weeks, the cerebral blood flow was strongly reduced (below reference level) and the hypersignal disappeared from the MRI scan, although the lesion was permanent as histologically assessed post-mortem. The MRI data were similar in the second monkey. Our experiments suggest that LSI and MRI, although they reflect different features, vary in parallel during a few weeks following an excitotoxic cortical lesion.
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Affiliation(s)
- Jörn Peuser
- University of Fribourg, Department of Physics, Ch. du Musée 3, CH-1700 Fribourg, Switzerland
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Rodríguez-Yáñez M, Sobrino T, Arias S, Vázquez-Herrero F, Brea D, Blanco M, Leira R, Castellanos M, Serena J, Vivancos J, Dávalos A, Castillo J. Early biomarkers of clinical-diffusion mismatch in acute ischemic stroke. Stroke 2011; 42:2813-8. [PMID: 21836082 DOI: 10.1161/strokeaha.111.614503] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
BACKGROUND AND PURPOSE Clinical-diffusion mismatch (CDM; National Institutes of Health Stroke Scale score≥8 and diffusion-weighted imaging lesion volume<25 mL) has been suggested as a surrogate of ischemic brain at risk of infarction and might be used to recognize salvageable ischemic tissue. Our aim was to identify early biomarkers associated with the presence of CDM. METHODS We prospectively evaluated CDM in 226 patients (71.6±11.1 years, 58% men) with hemispheric ischemic stroke within 12 hours from symptom onset (median, 3.6 hours). Diffusion-weighted MRI lesion volume was measured by manual segmentation method. Serum levels of glutamate, aspartate, interleukin-10, tumor necrosis factor-α, interleukin-6, S100β, neuron-specific enolase, intercellular adhesion molecule-1, vascular cell adhesion molecule-1, active matrix metalloproteinase-9, and cellular fibronectin were determined by immunoassay or high-performance liquid chromatography techniques in blood samples obtained at admission. RESULTS CDM was found in 61 patients (26.9%). Patients with CDM had higher serum levels of interleukin-10, tumor necrosis factor-α, and glutamate and lower serum levels of neuron-specific enolase, interleukin-6, and active matrix metalloproteinase-9 (all P<0.0001). Binary logistic regression showed that tumor necrosis factor-α≥21 pg/mL (OR, 21), glutamate≥230 μmol/L (OR, 27), neuron-specific enolase≥23 ng/mL (OR, 0.05), interleukin-6≥10 pg/mL (OR, 0.06), and active matrix metalloproteinase-9≥21 ng/mL (OR, 0.28) were independent molecular predictors of CDM after adjustment for covariates. The association of interleukin-10≥23 pg/mL and glutamate≥230 μmol/L levels predicted CDM with a sensitivity of 96% and a specificity of 98%. CONCLUSIONS High levels of interleukin-10, tumor necrosis factor-α, and glutamate as well as low levels of neuron-specific enolase, interleukin-6, and active matrix metalloproteinase-9 are associated with CDM.
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Affiliation(s)
- Manuel Rodríguez-Yáñez
- Neurovascular ARea, Department of Neurology, Clinical Neurosciences Research Laboratory, Hospital Clínico Universitario, University of Santiago de Comostela, Santiago de Compostela, Spain
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Hsu DP, Sandhu G, Yarmohammadi H, Sunshine JL. Intra-arterial stroke therapy: recanalization strategies, patient selection and imaging. Neuroimaging Clin N Am 2011; 21:379-90, xi. [PMID: 21640305 DOI: 10.1016/j.nic.2011.01.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
With more than 700,000 strokes per year resulting in greater than 160,000 deaths per year, stroke remains the leading cause of disability and third leading cause of death in the United States. Despite an overall decline in stroke mortality over the past 40 years, the total number of stroke deaths continues to increase, suggesting an increase in stroke incidence. The last 20 years of neuroscience advances have moved stroke from a condition that is monitored clinically and imaged serially as it evolves to an entity that can be treated acutely, with remarkable alterations in its natural history.
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Affiliation(s)
- Daniel P Hsu
- Department of Radiology, University Hospitals - Case Medical Center, 11100 Euclid Avenue, Cleveland, OH 44106, USA.
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25
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Srour JM, Shin W, Shah S, Sen A, Carroll TJ. SCALE-PWI: A pulse sequence for absolute quantitative cerebral perfusion imaging. J Cereb Blood Flow Metab 2011; 31:1272-82. [PMID: 21157469 PMCID: PMC3099632 DOI: 10.1038/jcbfm.2010.215] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The Bookend technique is a magnetic resonance imaging (MRI) dynamic susceptibility contrast method that provides reliable quantitative measurement of cerebral blood flow (CBF) and cerebral blood volume (CBV). The quantification is patient specific, is derived from a steady-state measurement of CBV, and is obtained from T(1) changes in the white matter and the blood pool after contrast agent injection. In the current implementation, the Bookend technique consists of three scanning steps requiring a cumulative scan time of 3 minutes 47 seconds, a well-trained technologist, and extra time for offline image reconstruction. We present an automation and acceleration of the multiscan Bookend protocol through a self-calibrating pulse sequence, namely Self-Calibrated Epi Perfusion-Weighted Imaging (SCALE-PWI). The SCALE-PWI is a single-shot echo-planar imaging pulse sequence with three modules and a total scan time of under 2 minutes. It provides the possibility of performing online, quantitative perfusion image reconstruction, which reduces the latency to obtain quantitative maps. A validation study in healthy volunteers (N=19) showed excellent agreement between SCALE-PWI and the conventional Bookend protocol (P>0.05 with Student's t-test, r=0.95/slope=0.98 for quantitative CBF, and r=0.91/slope=0.94 for quantitative CBV). A single MRI pulse sequence for absolute quantification of cerebral perfusion has been developed.
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Affiliation(s)
- Jessy Mouannes Srour
- Department of Biomedical Engineering, Northwestern University, 737 North Michigan Avenue, Chicago, IL 60611, USA
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Li YH, Li MH, Zhao JG, Wang W. MRI-based ultrafast protocol thrombolysis with rt-PA for acute ischemia stroke in 12-hour time window. J Neuroimaging 2010; 21:332-9. [PMID: 21121996 DOI: 10.1111/j.1552-6569.2010.00544.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
PURPOSE To evaluate the safety of thrombolysis with rt-PA in acute ischemic strokes during a 12-hour time window using an ultrafast MR protocol. METHODS Forty-six patients who met the clinical criteria (acute ischemic stroke within 12 hours after symptom onset; National Institutes of Health stroke scale score (NIHSS) of 4 to 22 and no intracranial hemorrhage on CT) and MRI selection criteria (acute ischemic stroke except lacunar and large DWI lesion) were treated with intravenous rt-PA. MRI was performed before rt-PA, and at 24 hours, 7 days, and 14 days after stroke. Clinical status was assessed using the NIHSS and Modified Rankin scale (mRS). RESULTS From 46 MRI-selected rt-PA patients, 43.5% (n= 20) were treated ≤3 hours (group A) and 56.5% (n= 26) after 3 to 12 hours (group B). No patients experienced symptomatic intracranial hemorrhage and the mortality rate was zero. No significant differences in age, gender, MRI lesion volumes, NIHSS score, and mRS were found between the 2 groups. Forty-five percent of the patients in group A and 46% in group B experienced a favorable outcome (P= .938). CONCLUSION Our results demonstrated the safety of thrombolysis with rt-PA in selected stroke patients within a 12-hour time window using an ultrafast MR protocol.
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Affiliation(s)
- Yue-Hua Li
- Institute of Diagnostic and Interventional Radiology, The Sixth Affiliated People's Hospital, Shanghai Jiao Tong University.
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Blackham KA, Tarr RW. Stroke: The vacuum cleaner for stroke. Nat Rev Neurol 2009; 5:582-3. [PMID: 19888314 DOI: 10.1038/nrneurol.2009.163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Latchaw RE, Alberts MJ, Lev MH, Connors JJ, Harbaugh RE, Higashida RT, Hobson R, Kidwell CS, Koroshetz WJ, Mathews V, Villablanca P, Warach S, Walters B. Recommendations for imaging of acute ischemic stroke: a scientific statement from the American Heart Association. Stroke 2009; 40:3646-78. [PMID: 19797189 DOI: 10.1161/strokeaha.108.192616] [Citation(s) in RCA: 286] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Sibon I, Ménégon P, Orgogozo JM, Asselineau J, Rouanet F, Renou P, Tourdias T, Pachai C, Chêne G, Dousset V. Inter- and intraobserver reliability of five MRI sequences in the evaluation of the final volume of cerebral infarct. J Magn Reson Imaging 2009; 29:1280-4. [PMID: 19472382 DOI: 10.1002/jmri.21779] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE To evaluate the reproducibility of fluid attenuated inversion recovery (FLAIR) and four other magnetic resonance imaging (MRI) sequences in the quantitative assessment of final cerebral infarct volume. MATERIALS AND METHODS FLAIR, T1-3D, magnetization transfer ratio (MTR)-map, diffusion-weighted trace (DWI)-trace, and apparent diffusion coefficient (ADC)-map, were acquired and measured in 33 patients 30-45 days after onset of a first-ever ischemic stroke. The infarct area was visually detected and manually delineated two times by two readers separately after images and sequences randomization. The reliability was assessed by using an intraclass correlation coefficient (ICC) and its two-sided 95% confidence interval (95% CI). RESULTS DWI-trace had the best reliability, with an ICC of 0.96 (95% CI = 0.93-0.98). FLAIR had an ICC of 0.86 (95% CI = 0.73-0.93), and a much higher volume. T1-3D, MTR-map and ADC-map had lower reliability or excessive volume values equal to 0 in comparison to DWI-trace. CONCLUSION DWI-trace performed within 30th and 45th day following onset of acute ischemic stroke was the most reliable sequence for final infarct volume quantification. This sequence should be added to FLAIR evaluation to strengthen the statistical results of the pharmacological trials and reduce their variability.
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Affiliation(s)
- Igor Sibon
- CHU Bordeaux, Department of Clinical Neurosciences, Bordeaux, France.
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Hakimelahi R, González RG. Neuroimaging of ischemic stroke with CT and MRI: advancing towards physiology-based diagnosis and therapy. Expert Rev Cardiovasc Ther 2009; 7:29-48. [PMID: 19105765 DOI: 10.1586/14779072.7.1.29] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Acute ischemic stroke is the third leading cause of death and the major cause of significant disability in adults in the USA and Europe. The number of patients who are actually treated for acute ischemic stroke is disappointingly low, despite availability of effective treatments. A major obstacle is the short window of time following stroke in which therapies are effective. Modern imaging is able to identify the ischemic penumbra, a key concept in stroke physiology. Evidence is accumulating that identification of a penumbra enhances patient management, resulting in significantly improved outcomes. Moreover, unexpectedly large proportions of patients have a substantial ischemic penumbra beyond the traditional time window and are suitable for therapy. The widespread availability of modern MRI and computed tomography systems presents new opportunities to use physiology to guide ischemic stroke therapy in individual patients. This article suggests an evidence-based alternative to contemporary acute ischemic stroke therapy.
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Affiliation(s)
- Reza Hakimelahi
- Neuroradiology Division, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
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Perfusion CT of the Brain Using 40-mm-Wide Detector and Toggling Table Technique for Initial Imaging of Acute Stroke. AJR Am J Roentgenol 2008; 191:W120-6. [DOI: 10.2214/ajr.07.2519] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Matsushima S, Kubota T, Yamada K, Akazawa K, Masunami T, Ito H, Ushijima Y, Owada K, Sasajima H, Mineura K, Nishimura T. Effect of vascular stenosis on perfusion-weighted imaging; differences between calculation algorithms. J Magn Reson Imaging 2008; 27:1103-8. [PMID: 18425825 DOI: 10.1002/jmri.21362] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
PURPOSE To determine the most suitable postprocessing technique for magnetic resonance (MR) perfusion imaging in patients with vascular stenosis, by comparing the cerebral blood flow (CBF) maps of single photon emission tomography (SPECT) and perfusion MR imaging (MRI). MATERIALS AND METHODS In 15 consecutive patients (14 men and one woman, mean age 73.9 +/- 6.0 years) with stenosis of common carotid artery (CCA) or internal carotid artery (ICA) of more than 75%, both brain perfusion MRI and brain perfusion SPECT were performed. From perfusion MR images, CBF maps were calculated with the first moment, singular value decomposition (SVD), and block circulant SVD (b-SVD) methods, and CBF maps from each algorithm were compared with those from SPECT. RESULTS The b-SVD method had the best correlation with SPECT (R = 0.814), followed by the first moment method (R = 0.776) and the SVD method (R = 0.723). The b-SVD method has the least mean difference with SPECT (0.118), the first moment method also had less difference (0.121), and the SVD had greatest mean difference (0.164). CONCLUSION Our results suggest that in patients with vascular impairment the b-SVD method will be the technique of choice rather than SVD or first moment method.
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Affiliation(s)
- Shigenori Matsushima
- Department of Radiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
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Provenzale JM, Shah K, Patel U, McCrory DC. Systematic review of CT and MR perfusion imaging for assessment of acute cerebrovascular disease. AJNR Am J Neuroradiol 2008; 29:1476-82. [PMID: 18583410 DOI: 10.3174/ajnr.a1161] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Perfusion imaging sequences are an important part of imaging studies designed to provide information to guide therapy for treatment of cerebrovascular disease. The purpose of this study was to perform a meta-analysis of the medical literature on perfusion imaging to determine its role in clinical decision making for patients with acute cerebral ischemia. MATERIALS AND METHODS We searched MEDLINE by using a strategy that combined terms related to perfusion imaging with terms related to acute cerebral ischemia and brain tumors. We identified 658 perfusion imaging articles and classified them according to the clinical usefulness criteria of Thornbury and Fryback. We found 59 articles with promise of indicating usefulness in clinical decision making. We devised and implemented a clinical decision making scoring scale more appropriate to the topic of acute cerebral ischemia. RESULTS Several articles provided important insights into the physiologic processes underlying acute cerebral ischemia by correlation of initial perfusion imaging deficits with clinical outcome or ultimate size of the infarct. However, most articles showed relatively low relevance to influencing decisions in implementing treatment. CONCLUSION Most perfusion imaging articles are oriented toward important topics such as optimization of imaging parameters, determination of ischemia penumbra, and prediction of outcome. However, information as to the role of perfusion imaging in clinical decision making is lacking. Studies are needed to demonstrate that use of perfusion imaging changes outcome of patients with acute cerebral ischemia.
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Affiliation(s)
- J M Provenzale
- Department of Radiology, Duke University Medical Center, Durham, NC 27710-3808, USA.
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Comparison of combined venous and arterial thrombolysis with primary arterial therapy using recombinant tissue plasminogen activator in acute ischemic stroke. J Stroke Cerebrovasc Dis 2008; 17:121-8. [PMID: 18436152 DOI: 10.1016/j.jstrokecerebrovasdis.2007.12.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2007] [Revised: 11/28/2007] [Accepted: 12/07/2007] [Indexed: 11/22/2022] Open
Abstract
OBJECTIVE We sought to compare the safety and efficacy of combined intravenous (IV) and intra-arterial (IA) thrombolysis with primary IA therapy using tissue plasminogen activator for acute ischemic stroke presenting within 6 hours of symptom onset. METHODS We performed quasirandomization of a single institution's prospectively collected stroke database, comparing IV/IA (0.6 mg/kg IV < or = 60 mg, followed by 0.3 mg/kg IA < or = 30 mg) versus primary IA. Outcome measures include 90-day modified Rankin scale score, mortality, symptomatic intracerebral hemorrhage, and recanalization rates. Statistical analysis was performed using bivariate and propensity score methods. RESULTS Of 1057 patients, 41 patients were treated with IV/IA, and 55 with IA. There was significant difference in time to treatment (mean of 151 minutes for the combined group and 261 minutes for the IA, P < .0001) and arterial tissue plasminogen activator dose (17.5 mg for IV/IA v 22.8 mg for IA only, P = .05). Propensity score matching yielded 25 patients in each group. Symptomatic intracerebral hemorrhage rate was 12% in each group. Mortality was 20% in the IV/IA group versus 16% in the IA group (relative risk 1.3 [0.4-4.1], P = .7). More patients in IV/IA group had modified Rankin scale score less than or equal to 2 (odds ratio 1.6 [0.5-5.8], P = .3). Recanalization was 64% with IV/IA versus 48% with IA (odds ratio 1.9 [0.5-7.0], P = .3). CONCLUSION This study demonstrates that both combined IV/IA and primary IA recombinant tissue plasminogen activator therapy is feasible and safe in the treatment of acute ischemic stroke. Combined IV/IA therapy may be associated with an improvement in clinical outcome without a significant increase in the risk of symptomatic intracerebral hemorrhage and mortality compared with IA therapy.
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Shanmuganathan K, Gullapalli RP, Zhuo J, Mirvis SE. Diffusion tensor MR imaging in cervical spine trauma. AJNR Am J Neuroradiol 2008; 29:655-9. [PMID: 18238846 PMCID: PMC7978215 DOI: 10.3174/ajnr.a0916] [Citation(s) in RCA: 132] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2007] [Accepted: 11/04/2007] [Indexed: 12/13/2022]
Abstract
BACKGROUND AND PURPOSE Our aim was to investigate the extent and severity of changes in spinal cord diffusion tensor imaging (DTI) parameters in patients with cervical cord injury. MATERIALS AND METHODS DTI was performed in 20 symptomatic patients (mean, 45.7 +/- 17.7 years of age; 2 women, 18 men) with cervical spine trauma and 8 volunteers (mean, 34.2 +/- 10.7 years of age; 6 men, 2 women). The whole cord and regional apparent diffusion coefficient (ADC), fractional anisotropy (FA), relative anisotropy (RA), and volume ratio (VR) of patients and volunteers were compared. DTI parameters were calculated in 16 patients. MR imaging demonstrated hemorrhagic cord contusions (n = 6), nonhemorrhagic cord contusions (n = 4), and soft-tissue injury (n = 6). Medical records were reviewed for extent of neurologic deficit. RESULTS Regional ADC values differed significantly between upper and mid and upper and lower (both, P < .004) cervical cord sections. FA was significantly different between upper and lower sections (P < .03). Whole cord ADC values were significantly lower in patients than in volunteers (P < .0001). Whole spine FA was not significantly decreased in patients (P < .06). ADC and FA values were significantly decreased at injury sites when compared with volunteers (P < .031 and .0001, respectively). The greatest differences in whole cord ADC, FA, RA, and VR were in patients with hemorrhagic cord contusions compared with healthy volunteers (P < .0001, .003, .0005, and .008, respectively). CONCLUSION DTI parameters are sensitive markers of cervical cord injury, with ADC showing the greatest sensitivity. Changes in DTI parameters are most marked at injury sites and reflect the severity of cord injury.
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Affiliation(s)
- K Shanmuganathan
- Department of Diagnostic Radiology, University of Maryland Medical Center, Baltimore, MD 21201, USA.
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Shin W, Horowitz S, Ragin A, Chen Y, Walker M, Carroll TJ. Quantitative cerebral perfusion using dynamic susceptibility contrast MRI: evaluation of reproducibility and age- and gender-dependence with fully automatic image postprocessing algorithm. Magn Reson Med 2008; 58:1232-41. [PMID: 17969025 DOI: 10.1002/mrm.21420] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
A novel approach for quantifying cerebral blood flow (CBF) is proposed that combines the bookend technique of calculating cerebral perfusion with an automatic postprocessing algorithm. The reproducibility of the quantitative CBF (qCBF) measurement in healthy controls (N = 8) showed a higher intraclass correlation coefficient (ICC) and lower coefficient of variation (COV) when calculated with automatic analysis (ICC/COV = 0.90/0.09) than when compared to conventional manual analysis (ICC/COV = 0.58/0.19). Also, the reproducibility in patients (N = 25) was successfully evaluated with the automatic analysis (ICC/COV = 0.81/0.14). In 175 consecutive clinical scans, we found 3.0% and 7.4% of qCBF decrease per decade in white matter (WM) (21.5 +/- 6.66 ml/100 g-min) and gray matter (GM) (49.6 +/- 16.2 ml/100 g-min), respectively. Cerebral blood volume (CBV) showed a significant 3.7% decrease per decade in GM (3.00 +/- 0.94 ml/100 g) but not in WM (1.69 +/- 0.40 ml/100 g). Mean transit time (MTT) increased by 1.9% and 3.8% per decade in WM (5.04 +/- 0.88 s) and GM (4.14 +/- 0.80 s), respectively. qCBF and MTT values between males (N = 85) and females (N = 90) were significantly different in GM. Women showed 11% higher qCBF as well as a higher decrease in qCBF with increasing age than men in the whole brain (WB). Our results supported the notion that population average empirical quantification of cerebral perfusion is subject to individual variation as well as age- and gender-dependent variability.
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Affiliation(s)
- Wanyong Shin
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, USA
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Harris AD, Govindaraj M, Frayne R. Minimum detectable difference of MR diffusion maps in acute ischemic stroke. J Magn Reson Imaging 2008; 27:629-33. [DOI: 10.1002/jmri.21166] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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Wittsack HJ, Wohlschläger A, Ritzl E, Kleiser R, Cohnen M, Seitz R, Mödder U. CT-perfusion imaging of the human brain: Advanced deconvolution analysis using circulant singular value decomposition. Comput Med Imaging Graph 2008; 32:67-77. [DOI: 10.1016/j.compmedimag.2007.09.004] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2006] [Revised: 09/24/2007] [Accepted: 09/25/2007] [Indexed: 11/17/2022]
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Kim HS, Kim SY, Kim JM. Underestimation of Cerebral Perfusion on Flow-Sensitive Alternating Inversion Recovery Image: Semiquantitative Evaluation with Time-to-Peak Values. AJNR Am J Neuroradiol 2007; 28:2008-13. [PMID: 17898193 PMCID: PMC8134235 DOI: 10.3174/ajnr.a0720] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE We assessed the underestimation of cerebral perfusion measured by the flow-sensitive alternating inversion recovery (FAIR) technique in patients with carotid stenosis and compared the technique with dynamic susceptibility contrast (DSC) MR images. MATERIALS AND METHODS We studied 42 areas of decreased cerebral blood flow (CBF) using 3 FAIR images with different inversion times (TIs) in 42 consecutive patients with unilateral carotid stenosis of more than 50%. The width of decreased CBF area (wCBF) was qualitatively assessed. We analyzed the ratio of CBF (rCBF) and the time-to-peak (TTP) difference (dTTP) between the ipsilateral hemisphere to carotid stenosis and contralateral normal area using regions of interest (ROIs) at the same location. RESULTS In the areas with more prolonged TTP (dTTP > or =3.2 s), the wCBF obtained from the FAIR images with TI of 1600 ms was smaller than those from the FAIR images with a TI of 800 ms and 1200 ms in all cases. The mean rCBF obtained from the FAIR images with a TI of 1200 ms was significantly lower than that obtained from the FAIR images with a TI of 1600 ms (P < .01) in the areas with more prolonged TTP. In the areas with less prolonged TTP (dTTP <3.2 s), the wCBF and mean rCBF were not significantly different between the 2 FAIR images (TI, 1200 and 1600 ms). CONCLUSION If TTP is delayed significantly (dTTP > or =3.2 s), the FAIR with intermediate or short TI showed underestimation of perfusion in the same area with delay in TTP.
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Affiliation(s)
- H S Kim
- Department of Diagnostic Radiology, Ajou University, College of Medicine, Kyunggido, Republic of Korea.
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Krishnananthan R, Minoshima S, Lewis D. Tc-99m ECD Neuro-SPECT and Diffusion Weighted MRI in the Detection of the Anatomical Extent of Subacute Stroke. Clin Nucl Med 2007; 32:700-2. [PMID: 17710022 DOI: 10.1097/rlu.0b013e318123f7e6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
We present a case of subacute middle cerebral artery infarct, which demonstrates restricted diffusion on MRI and reperfusion hyperemia in the posterior half of the lesion on angiography. Tc-99m ethyl cysteinate dimer (ECD) SPECT obtained shortly after the MRI failed to demonstrate perfusion defects in the regions demonstrating reperfusion hyperemia on angiography, underestimating the true size of the infarct. Crossed cerebellar diaschisis is, however, present. SPECT studies obtained over the following weeks demonstrated gradual enlargement of the lesion to approximate the MRI signal changes over a 19-day period. The case presented demonstrates retention of ECD in the infarcted brain. Several studies have demonstrated that Tc-99m ECD uptake is dependent on preserved brain tissue function because tracer retention requires enzymatic esterase activity, rather than the passive, nonenergy dependent trapping of Tc-99m hexamethylpropyleneamine oxime. Hence, infarcted areas undergoing reperfusion hyperemia are unlikely to demonstrate ECD uptake. This report illustrates that MRI diffusion weighted imaging may be more accurate in demonstrating the full extent of reperfused infarcts earlier than Tc-99m ECD SPECT. SPECT in this case failed to demonstrate reduced uptake in reperfused regions of the infarct. Also, crossed cerebellar diaschisis may serve as an early marker of extensive neuronal dysfunction.
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Affiliation(s)
- Ruben Krishnananthan
- Division of Nuclear Medicine, University of Washington, Seattle, Washington 98195-7115, USA
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Kosior RK, Wright CJ, Kosior JC, Kenney C, Scott JN, Frayne R, Hill MD. 3-Tesla versus 1.5-Tesla Magnetic Resonance Diffusion and Perfusion Imaging in Hyperacute Ischemic Stroke. Cerebrovasc Dis 2007; 24:361-8. [PMID: 17690549 DOI: 10.1159/000106983] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2007] [Accepted: 04/24/2007] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Clinical 3-tesla magnetic resonance imaging systems are becoming widespread. No studies have examined differences between 1.5-tesla and 3-tesla imaging for the assessment of hyperacute ischemic stroke (<6 h from symptom onset). Our objective was to compare 1.5-tesla and 3-tesla diffusion and perfusion imaging for hyperacute stroke using optimized protocols. METHODS Three patients or their surrogate provided informed consent. Diffusion-weighted imaging (DWI) and perfusion-weighted imaging (PWI) was performed sequentially at 1.5 T and 3 T. DWI, apparent diffusion coefficient (ADC) maps and relative time-to-peak (TTP) maps were registered and assessed. DWI contrast-to-noise ratio (CNR) and ADC contrast were measured and compared. The infarct lesion volume (ILV) and thresholded ischemic volume (TIV) were estimated on the ADC and TTP maps, respectively, with the penumbral volume being defined as the difference between these volumes. RESULTS Qualitatively, the 3-tesla TTP images exhibited greater feature detail. Quantitatively, the DWI CNR and ILV were similar at both field strengths, the ADC contrast was greater at 3 T and the TIV and penumbral volumes were much smaller at 3 T. CONCLUSIONS Overall, the 3-tesla diffusion and perfusion images were at least as good and in some ways superior to the 1.5-tesla images for assessing hyperacute stroke. The TTP maps showed greater feature detail at 3 T. The ischemic and penumbra volumes were much greater at 1.5 T, indicating a potential difference in the diagnostic utility of the PWI-DWI mismatch between field strengths.
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Affiliation(s)
- Robert K Kosior
- Department of Electrical and Computer Engineering, University of Calgary, Calgary, Alta., Canada
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Leary MC, Caplan LR. Technology insight: brain MRI and cardiac surgery--detection of postoperative brain ischemia. ACTA ACUST UNITED AC 2007; 4:379-88. [PMID: 17589428 DOI: 10.1038/ncpcardio0915] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2006] [Accepted: 04/05/2007] [Indexed: 11/08/2022]
Abstract
Annually, an estimated 1 million patients undergo heart surgery worldwide. Unfortunately, stroke continues to be a frequent complication of cardiac surgery, with the specific cerebrovascular risk depending upon the particular surgical procedure performed. Neuroimaging has an integral role in the initial evaluation and management of patients who present with acute stroke symptoms following cardiac surgery. The aim of this paper is to review the role brain MRI has in detecting postoperative brain ischemia in these patients. Multimodal MRI--using diffusion-weighted MRI (DWI), perfusion-weighted MRI, and gradient-recalled echo imaging--has an excellent capacity to identify and delineate the size and location of acute ischemic strokes as well as intracerebral hemorrhages. This differentiation is critical in making appropriate treatment decisions in the acute setting, such as determining patient eligibility for thrombolytic or hemodynamic therapies. At present, DWI offers prognostic value in patients with strokes following cardiac surgery. Additionally, DWI could be a valuable tool for evaluating stroke preventive measures as well as therapeutic interventions in patients undergoing CABG surgery.
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Affiliation(s)
- Megan C Leary
- Harvard Clinical Research Institute, Boston, MA, USA
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Surikova I, Meisel S, Siebler M, Wittsack HJ, Seitz RJ. Significance of the perfusion-diffusion mismatch in chronic cerebral ischemia. J Magn Reson Imaging 2007; 24:771-8. [PMID: 16941614 DOI: 10.1002/jmri.20686] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
PURPOSE To determine whether the perfusion deficit could predict brain infarction in patients with chronic cerebral ischemia who experienced recurring episodes of neurological symptoms and showed a perfusion-diffusion mismatch on magnetic resonance (MR) images. MATERIALS AND METHODS In 53 consecutive patients (38 males and 15 females, 62+/-13 years old) with ischemia in the middle cerebral artery (MCA) territory, lesion volumetry was performed on parametric maps of the time-to-peak, the cerebral blood volume, and diffusion-weighted (DW) images. The infarct lesions were assessed on follow-up T2-weighted (T2W) MR images after eight days. Cerebrovascular changes were determined by time-of-flight (TOF) MR angiography (MRA). Inferential and correlation statistics were used. RESULTS Patients with chronic ischemic brain disease (N=39) who presented with a severe perfusion-diffusion mismatch in the presence of a normal cerebral blood volume had no or small brain infarctions as found on follow-up T2W images. MRA revealed widespread abnormalities of the basal cerebral arteries compatible with brain perfusion abnormalities. In contrast, in acute stroke patients (N=14) the deficit of cerebral perfusion predicted the infarct lesion in the T2W images. CONCLUSION Our results suggest that in chronic cerebral ischemia the normal blood volume was maintained despite the depression of cerebral perfusion and recurring minor insults.
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Affiliation(s)
- Irina Surikova
- Department of Neurology, Heinrich Heine University, Düsseldorf, Germany
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Tan PL, King D, Durkin CJ, Meagher TM, Briley D. Diffusion weighted magnetic resonance imaging for acute stroke: practical and popular. Postgrad Med J 2006; 82:289-92. [PMID: 16597819 PMCID: PMC2579637 DOI: 10.1136/pgmj.2005.038299] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AIM To evaluate the feasibility and impact of diffusion weighted magnetic resonance imaging (DW MRI) as the first line neuroimaging of stroke at a district general hospital. METHODS Prospective audit of all in-patients admitted with clinically suspected acute stroke and referred for imaging over a consecutive 17 week period. The data collected included scan type, time from cerebral event to imaging request, and time from formal radiological request to neuroimaging. Clinicians' (general physicians, neurologists, and radiologists) perceptions were assessed by a questionnaire. RESULTS 148 patients had neuroimaging for clinically suspected stroke during this period. Eighty one per cent of patients (120 of 148) had DW MRI as first line. Ninety two per cent of these patients had DW MRI within 24 hours of the formal radiological request. Twenty eight patients did not undergo DW MRI because lack of MRI safety, clinical state, unavailability because of maintenance service or lack of trained staff. Clinicians found the introduction of the DW MRI based service a significant improvement on computed tomography, especially for equivocal cases. CONCLUSION DW based MRI service is both feasible and sustainable in the setting of a district general hospital and most clinicians feel that this is a significant improvement to stroke services.
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Affiliation(s)
- P L Tan
- Department of Radiology, Stoke Mandeville Hospital, Mandeville Road, Aylesbury, Buckinghamshire HP21 8AL, UK
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Graves MJ, U-King-Im J, Howarth S, Gillard JH. Ultrafast magnetic resonance imaging protocols in stroke. Expert Rev Neurother 2006; 6:921-30. [PMID: 16784414 DOI: 10.1586/14737175.6.6.921] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Stroke is the third leading cause of death and morbidity in the Western world. Ever since the publication of the major randomized trials showing the benefit of thrombolysis in early acute stroke, there has been growing impetus for the diagnosis of acute stroke to become a medical emergency. Currently, computed tomography (CT) remains the diagnostic method of choice in the assessment of acute strokes. It is practical, rapid, and widely available and, as used in these trials, can robustly exclude acute hemorrhage before potential thrombolysis. Although magnetic resonance imaging (MRI) has a number of advantages over unenhanced CT, the practicalities of performing MRI in the acute setting have hampered its widespread use. There are several reasons why speed of imaging is paramount in acute strokes. Firstly, such patients are often unwell and agitated and, as such, require close monitoring. Moreover, because of the short window within which intravenous thrombolysis can be given, time-consuming imaging studies decrease the therapeutic options available and likelihood of successful intervention. This review summarizes the latest developments in ultrafast imaging protocols that have the potential to improve practical feasibility, and thus propel MRI back to the forefront of acute stroke imaging.
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Affiliation(s)
- Martin J Graves
- University of Cambridge Hospitals NHS Foundation Trust, Departments of Radiology and Medical Physics, Hills Road, Cambridge, CB2 2QQ, UK.
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Abstract
Stroke is a devastating disease with a complex pathophysiology. It is a major cause of death and disability in North America. To fully characterize its extent and effects, one requires numerous specialized anatomical and functional MR techniques, specifically diffusion-weighted imaging, MR angiography, and perfusion-weighted imaging. The advent of 3.0 T clinical scanners has the potential to provide higher quality information in potentially less time compared with 1.5 T stroke-specific MR imaging protocols. This article gives a brief overview of stroke, presents the principles and clinical applications of the relevant MR techniques required for diagnostic stroke imaging at high field, and discusses the advantages, challenges, and limitations of 3.0 T imaging as they relate to stroke.
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Cruz LCH, Sorensen AG. Diffusion Tensor Magnetic Resonance Imaging of Brain Tumors. Magn Reson Imaging Clin N Am 2006; 14:183-202. [PMID: 16873010 DOI: 10.1016/j.mric.2006.06.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
DTI seems to offer the possibility of adding important information to presurgical planning. Although experience is limited, DTI seems to provide useful local information about the structures near the tumor, and this seems to be useful in planning. In the future, DTI may provide an improved way to monitor intraoperative surgical procedures as well as their complications. Furthermore, evaluation of the response to treatment with chemotherapy and radiation therapy might also be possible. Although DTI has some limitations, its active investigation and further study are clearly warranted.
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Affiliation(s)
- L Celso Hygino Cruz
- Clínica de Diagnóstico por Imagem, Multi-Imagem Ressonância Magnética, Av. das Ameréricas 4666, Centro Médico Barrashopping, Rio de Janeiro, Brazil
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Abstract
As new treatments are developed for stroke, the potential clinical applications of CT perfusion (CTP) imaging in the diagnosis, triage, and therapeutic monitoring of these diseases are certain to increase. Technical advances in scanner hardware and software should no doubt continue to increase the speed, coverage, and resolution of CTP imaging. CTP offers the promise of efficient use of imaging resources and, potentially, of decreased morbidity. Most importantly, current CT technology already permits the incorporation of CTP as part of an all-in-one acute stroke examination to answer the four fundamental questions of stroke triage quickly and accurately, further increasing the contribution of imaging to the diagnosis and treatment of acute stroke.
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Affiliation(s)
- Sanjay K Shetty
- Department of Radiology, Massachusetts General Hospital, Boston, MA 02114, USA.
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Abstract
Acute stroke therapy is evolving rapidly as research moves toward extending the time window for treatment so that more patients can benefit. As physiology-based imaging increasingly is used in patient selection, it is becoming evident that rigid time windows are not applicable to individual patients. Xenon CT has an important role in acute stroke therapeutic intervention as a quantitative, reproducible, rapid, and safe modality, which can provide valuable physiologic data that can optimize patient triage and aid in management.
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Affiliation(s)
- Rishi Gupta
- Department of Neurology, Stroke Institute, University of Pittsburgh Medical Center, Pittsburgh, PA 15213, USA
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Abstract
Stroke carries a severe toll in terms of loss of life and disability for patients and their families. Until 10 years ago, physicians, and in particular neurologists, had a conservative, nonaggresive approach to this devastating disease. The advent of thrombolytic therapy not only proved that acute ischemic stroke is treatable, but also that early reperfusion can dramatically change the outcome of acute stroke patients. As a result of these trials, intravenous (IV) tissue plasminogen activator (t-PA) has been approved for treatment of acute ischemic stroke within 3 hours after symptom onset in the United States, Canada, Australia, and the European Union. The near future is extremely promising. Imaging modalities, such as diffusion- and perfusion-weighted images, as well as CT perfusion and CT angiography, to better select patients for treatment are now routinely performed in most academic medical centers. Novel IV and intra-arterial (IA) agents have been developed and tested. Emerging therapies will soon be available to increase the therapeutic windows for thrombolysis both by better screening patients using MRI or CT and by new IV and IA treatments. Several multicenter controlled trials in both imaging-guided decisions and therapeutic agents are either completed or being performed. We review data on advancement in imaging and treatment of acute ischemic stroke, in particular focusing on pharmacologic and mechanical IA thrombolysis.
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Affiliation(s)
- Italo Linfante
- Section of Neuroimaging and Intervention, Department of Radiology, University of Massachusetts, Memorial University Campus, 55 Lake Avenue North, Worcester, MA 01655, USA.
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