scholarly journals Ischemic Penumbra: A Personal View

2021 ◽  
pp. 1-10
Author(s):  
Stephen M. Davis ◽  
Geoffrey A. Donnan
Keyword(s):  
Time Window ◽  
Imaging Techniques ◽  
Intravenous Thrombolysis ◽  
Ischemic Penumbra ◽  
Mobile Platforms ◽  
Personal View ◽  
Penumbral Imaging ◽  
Positron Emission ◽  
Slow Growing ◽  
Over 40 Years

The concept of the ischemic penumbra was defined over 40 years ago by Lindsay Symon and his group and is now an established principle of all acute ischemic stroke therapies. These reperfusion treatments rescue threatened, critically hypoperfused brain tissue and have been proven to improve clinical outcomes. We have been fortunate to have observed and played a small part in the penumbral story from its beginnings in the 1970s to its pivotal position today. Over this period, we have witnessed penumbral imaging evolve from positron emission tomography through to magnetic resonance imaging and now predominantly computed tomography perfusion, with the advent of automated imaging facilitating case selection for reperfusion therapies. We and others have conducted clinical trials using penumbral imaging to extend the time window for intravenous thrombolysis and select patients for thrombectomy. Together with the concept of fast- and slow-growing ischemic infarct patterns, this embeds the penumbral principle in everyday clinical management. The opportunity now exists to make penumbral imaging even more portable, affordable, and more widely available using mobile platforms, novel imaging techniques, digital linkage, and artificial intelligence.

scholarly journals The ischemic penumbra: From concept to reality

2020 ◽  
pp. 174749302097522
Author(s):  
Charlotte M Ermine ◽  
Andrew Bivard ◽  
Mark W Parsons ◽  
Jean-Claude Baron
Keyword(s):  
Clinical Practice ◽  
Animal Studies ◽  
Treatment Time ◽  
Time Window ◽  
Imaging Techniques ◽  
Reperfusion Therapy ◽  
Ischemic Penumbra ◽  
Positron Emission ◽  
Imaging Research ◽  
Ischaemic Penumbra

The discovery that brain tissue could potentially be salvaged from ischaemia due to stroke, has led to major advances in the development of therapies for ischemic stroke. In this review, we detail the advances in the understanding of this area termed the ischaemic penumbra, from its discovery to the evolution of imaging techniques, and finally some of the treatments developed. Evolving from animal studies from the 70s and 80s and translated to clinical practice, the field of ischemic reperfusion therapy has largely been guided by an array of imaging techniques developed to positively identify the ischemic penumbra, including positron emission tomography, computed tomography and magnetic resonance imaging. More recently, numerous penumbral identification imaging studies have allowed for a better understanding of the progression of the ischaemic core at the expense of the penumbra, and identification of patients than can benefit from reperfusion therapies in the acute phase. Importantly, 40 years of critical imaging research on the ischaemic penumbra have allowed for considerable extension of the treatment time window and better patient selection for reperfusion therapy. The translation of the penumbra concept into routine clinical practice has shown that “tissue is at least as important as time.”

A Novel Secure and Robust encryption scheme for medical images

2020 ◽  
Vol 16 ◽  
Author(s):  
Siyamol Chirakkarottu ◽  
Sheena Mathew
Keyword(s):  
Medical Images ◽  
Technological Development ◽  
Imaging Techniques ◽  
Chaotic Map ◽  
Two Phase ◽  
Positron Emission ◽  
Medical Diagnostic ◽  
Wireless Medium ◽  
Health Care Applications ◽  
Magnetic Resonance Imaging Mri

Background: Medical imaging encloses different imaging techniques and processes to image the human body for medical diagnostic and treatment purposes. Hence it plays an important role to improve public health. The technological development in biomedical imaging specifically in X-ray, Computed Tomography (CT), nuclear ultrasound including Positron Emission Tomography (PET), optical and Magnetic Resonance Imaging (MRI) can provide valuable information unique to a person. Objective: In health care applications, the images are needed to be exchanged mostly over wireless medium. The diagnostic images with confidential information of a patient need to be protected from unauthorized access during transmission. In this paper, a novel encryption method is proposed to improve the security and integrity of medical images. Methods: Chaotic map along with DNA cryptography is used for encryption. The proposed method describes a two phase encryption of medical images. Results: Performance of the proposed method is also tested by various analysis metrics. Robustness of the method against different noises and attacks is analyzed. Conclusion: The results show that the method is efficient and well suitable to medical images.

scholarly journals Recent Progress in the Molecular Imaging of Nonalcoholic Fatty Liver Disease

2021 ◽  
Vol 22 (14) ◽  
pp. 7348
Author(s):  
Olivia Wegrzyniak ◽  
Maria Rosestedt ◽  
Olof Eriksson
Keyword(s):  
Liver Disease ◽  
Molecular Imaging ◽  
Fatty Liver ◽  
Nonalcoholic Fatty Liver Disease ◽  
Fatty Liver Disease ◽  
Imaging Techniques ◽  
Current Status ◽  
Nonalcoholic Fatty Liver ◽  
Positron Emission ◽  
Activated Fibroblasts

Pathological fibrosis of the liver is a landmark feature in chronic liver diseases, including nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH). Diagnosis and assessment of progress or treatment efficacy today requires biopsy of the liver, which is a challenge in, e.g., longitudinal interventional studies. Molecular imaging techniques such as positron emission tomography (PET) have the potential to enable minimally invasive assessment of liver fibrosis. This review will summarize and discuss the current status of the development of innovative imaging markers for processes relevant for fibrogenesis in liver, e.g., certain immune cells, activated fibroblasts, and collagen depositions.

scholarly journals In Vivo Imaging of Biodegradable Implants and Related Tissue Biomarkers

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2348
Author(s):  
Leon Riehakainen ◽  
Chiara Cavallini ◽  
Paolo Armanetti ◽  
Daniele Panetta ◽  
Davide Caramella ◽  
...  
Keyword(s):  
Imaging Modality ◽  
Imaging Techniques ◽  
Special Focus ◽  
Tissue Remodelling ◽  
Biodegradable Implant ◽  
Advantages And Disadvantages ◽  
Non Invasive ◽  
Positron Emission ◽  
Longitudinal Imaging

Non-invasive longitudinal imaging of osseointegration of bone implants is essential to ensure a comprehensive, physical and biochemical understanding of the processes related to a successful implant integration and its long-term clinical outcome. This study critically reviews the present imaging techniques that may play a role to assess the initial stability, bone quality and quantity, associated tissue remodelling dependent on implanted material, implantation site (surrounding tissues and placement depth), and biomarkers that may be targeted. An updated list of biodegradable implant materials that have been reported in the literature, from metal, polymer and ceramic categories, is provided with reference to the use of specific imaging modalities (computed tomography, positron emission tomography, ultrasound, photoacoustic and magnetic resonance imaging) suitable for longitudinal and non-invasive imaging in humans. The advantages and disadvantages of the single imaging modality are discussed with a special focus on preclinical imaging for biodegradable implant research. Indeed, the investigation of a new implant commonly requires histological examination, which is invasive and does not allow longitudinal studies, thus requiring a large number of animals for preclinical testing. For this reason, an update of the multimodal and multi-parametric imaging capabilities will be here presented with a specific focus on modern biomaterial research.

scholarly journals The Clinical Value of PET with Amino Acid Tracers for Gliomas WHO Grade II

2011 ◽  
Vol 2011 ◽  
pp. 1-11 ◽  
Author(s):  
Anja Smits ◽  
Brigitta G. Baumert
Keyword(s):  
Amino Acid ◽  
Hot Spot ◽  
Imaging Techniques ◽  
Biological Behavior ◽  
Optimal Timing ◽  
Low Grade ◽  
Clinical Value ◽  
Who Grade ◽  
Positron Emission ◽  
Therapeutic Procedures

The clinical management of adults with low-grade gliomas (LGGs) remains a challenge. There is no curative treatment, and management of individual patients is a matter of deciding optimal timing as well as right treatment modality. In addition to conventional imaging techniques, positron emission tomography (PET) with amino acid tracers can facilitate diagnostic and therapeutic procedures. In this paper, the clinical applications of PET with amino acid tracers 11C-methyl-L-methionine (MET) and 18F-fluoro-ethyl-L-tyrosine (FET) for patients with LGG are summarized. We also discuss the value of PET for the long-term followup of this patient group. Monitoring metabolic activity by PET in individual patients during course of disease will provide insight in the biological behavior and evolution of these tumors. As such, spatial changes in tumor activity over time, including shifts of hot-spot regions within the tumor, may reflect intratumoral heterogeneity and correlate to clinical parameters.

scholarly journals News about the Role of Fluid and Imaging Biomarkers in Neurodegenerative Diseases

Biomedicines ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 252
Author(s):  
Jacopo Meldolesi
Keyword(s):  
Neurodegenerative Diseases ◽  
Imaging Techniques ◽  
Imaging Biomarkers ◽  
Positron Emission ◽  
Specific Proteins ◽  
Great Relevance ◽  
The Brain ◽  
Positive Point

Biomarkers are molecules that are variable in their origin, nature, and mechanism of action; they are of great relevance in biology and also in medicine because of their specific connection with a single or several diseases. Biomarkers are of two types, which in some cases are operative with each other. Fluid biomarkers, started around 2000, are generated in fluid from specific proteins/peptides and miRNAs accumulated within two extracellular fluids, either the central spinal fluid or blood plasma. The switch of these proteins/peptides and miRNAs, from free to segregated within extracellular vesicles, has induced certain advantages including higher levels within fluids and lower operative expenses. Imaging biomarkers, started around 2004, are identified in vivo upon their binding by radiolabeled molecules subsequently revealed in the brain by positron emission tomography and/or other imaging techniques. A positive point for the latter approach is the quantitation of results, but expenses are much higher. At present, both types of biomarker are being extensively employed to study Alzheimer’s and other neurodegenerative diseases, investigated from the presymptomatic to mature stages. In conclusion, biomarkers have revolutionized scientific and medical research and practice. Diagnosis, which is often inadequate when based on medical criteria only, has been recently improved by the multiplicity and specificity of biomarkers. Analogous results have been obtained for prognosis. In contrast, improvement of therapy has been limited or fully absent, especially for Alzheimer’s in which progress has been inadequate. An urgent need at hand is therefore the progress of a new drug trial design together with patient management in clinical practice.

Distinct Imaging Modalities in Head and Neck Cancer: Benefits and Drawbacks

2020 ◽  
Vol 11 (SPL4) ◽  
pp. 2777-2784
Author(s):  
Dana Merin ◽  
Roshni P R
Keyword(s):  
Head And Neck Cancer ◽  
Head And Neck ◽  
Neck Cancer ◽  
Imaging Techniques ◽  
Precise Determination ◽  
Imaging Biomarkers ◽  
Selection Strategies ◽  
Positron Emission ◽  
Before And After ◽  
Oncological Imaging

This review mainly focuses on the distinct imaging techniques in for head and neck cancer (HNC), its altered techniques used in diagnosis and its applications. It also depicts the upcoming imaging methods present in the field of HNC causing areas. It explains precise determination regarding the degree and extends of neoplasm. We mainly look on to the MRI(Magnetic resonance imaging), PET(Positron emission tomography), CT (computed tomography)imaging biomarkers for the management of HNC. It plays an important role in the therapy selection strategies and also enhances the therapeutic ratio in the management of HNC. The role of imaging techniques become increasingly more crucial in the management process in locally progressed head and neck squamous cell carcinoma(HNSCC). In this structure, PET allows non-invasive assessment of a range of tumour biomarkers such as metabolism, hypoxia and proliferation. MRI techniques such as can characterize different tissues by probing into their microstructure, providing a novel methodology in oncological imaging. CT, MRI, and PET/CT are widely used to determine the presence and extent of the tumours before and after treatment. This review depicts a synopsis of the most recent imaging strategies and imaging recommendations for every one of the different strides along the clinical way of patients with head and neck malignant growth.

Abstract WP112: Thrombolysis for AIS in the Unwitnessed or Extended Therapeutic Time Window: A Systematic Review and Meta-Analysis

Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Aristeidis H Katsanos ◽  
Konark Malhotra ◽  
Amrou Sarraj ◽  
Andrew Barreto ◽  
Martin Köhrmann ◽  
...  
Keyword(s):  
Symptom Onset ◽  
Time Window ◽  
Meta Analysis ◽  
Onset Time ◽  
Intravenous Thrombolysis ◽  
Functional Independence ◽  
Functional Improvement ◽  
Increased Risk ◽  
Significant Difference ◽  
All Cause Mortality

Introduction: We sought to assess the utility of intravenous thrombolysis (IVT) treatment in acute ischemic stroke (AIS) patients with unclear symptom onset time or outside the 4.5 hour time window, selected by advanced neuroimaging. Methods: We performed random-effects meta-analyses on the unadjusted and adjusted for potential confounders associations of IVT (alteplase 0.9 mg/kg) with the following outcomes: 3-month favorable functional outcome [FFO, modified Rankin Scale (mRS) scores: 0-1], 3-month functional independence (FI, mRS-scores: 0-2), 3-month mortality, 3-month functional improvement (assessed with ordinal analysis on the mRS-scores), symptomatic intracranial hemorrhage (sICH) and complete recanalization (CR). Results: We identified 4 eligible RCTs (859 total patients). In unadjusted analyses IVT was associated with higher likelihood of 3-month FFO (OR=1.48, 95%CI:1.12-1.96), FI (OR=1.42, 95%CI:1.07-1.90), sICH (OR=5.28, 95%CI:1.35-20.68) and CR (OR=3.29, 95%CI:1.90-5.69), with no significant difference in the odds of all-cause mortality risk at three months (OR=1.75, 95%CI: 0.93-3.29). In the adjusted analyses IVT was also associated with higher odds of 3-month FFO (OR adj =1.62, 95%CI:1.20-2.20), functional improvement (OR adj =1.42, 95%CI: 1.11-1.81) and sICH (OR adj =6.22, 95%CI: 1.37-28.26). There was no association between IVT and FI (OR adj =1.61, 95%CI: 0.94-2.75) or all-cause mortality at three months (OR adj =1.75, 95%CI: 0.93-3.29). No evidence of heterogeneity was evident in any of the analyses (I 2 =0). Conclusion: IVT in AIS patients with unknown symptom onset time or elapsed time from symptom onset more than 4.5 hours, selected with advanced neuroimaging, results in a higher likelihood of complete recanalization and functional improvement at three months despite the increased risk of sICH.

Basics of Imaging Techniques in Evaluation of Soft Tissue Tumors

2017 ◽  
Author(s):  
Emily Alanna Aherne ◽  
Sinchun Hwang
Keyword(s):  
Magnetic Resonance Imaging ◽  
Computed Tomography ◽  
Positron Emission Tomography ◽  
Magnetic Resonance ◽  
Soft Tissue ◽  
Imaging Techniques ◽  
Soft Tissue Tumors ◽  
Emission Tomography ◽  
Resonance Imaging ◽  
Positron Emission

Medical imaging plays a pivotal role in the detection, diagnosis, and clinical management of primary soft tissue tumors. Various imaging modalities have been used, and each modality offers unique advantages in the workup of soft tissue tumors by localizing the lesions in different compartments of the body and characterizing macroscopic tissue composition of the lesions in a noninvasive and safe manner. We review the clinical role and technical aspects of the frequently used imaging modalities, including magnetic resonance imaging (MRI), computed tomography, ultrasonography, positron emission tomography, and plain radiography with an emphasis on MRI as a mainstay imaging modality and a brief discussion of advanced techniques. We also review imaging features of common soft tissue tumors that can be detected and characterized using current imaging techniques. This review contains 54 figures, 1 table and 37 references.   Key words: computed tomography, diffusion-weighted imaging, imaging, magnetic resonance imaging, positron emission tomography, soft tissue, technique, tumor, ultrasonography

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