scholarly journals Acute Astrocyte Activation in Brain Detected by Mri: New Insights into T1 Hypointensity

2007 ◽  
Vol 28 (3) ◽  
pp. 621-632 ◽  
Author(s):  
Nicola R Sibson ◽  
John P Lowe ◽  
Andrew M Blamire ◽  
Matthew J Martin ◽  
Tiho P Obrenovitch ◽  
...  
Keyword(s):  
Experimental Models ◽  
Low Flow ◽  
Astrocyte Activation ◽  
Tissue Water ◽  
Signal Change ◽  
Apparent Diffusion ◽  
Acute Increase ◽  
Magnetic Resonance Imaging Mri ◽  
The Brain ◽  
Intrastriatal Injection

Increases in the T1 of brain tissue, which give rise to dark or hypointense areas on T1-weighted images using magnetic resonance imaging (MRI), are common to a number of neuropathologies including multiple sclerosis (MS) and ischaemia. However, the biologic significance of T1 increases remains unclear. Using a multiparametric MRI approach and well-defined experimental models, we have experimentally induced increases in tissue T1 to determine the underlying cellular basis of such changes. We have shown that a rapid acute increase in T1 relaxation in the brain occurs in experimental models of both low-flow ischaemia induced by intrastriatal injection of endothelin-1 (ET-1), and excitotoxicity induced by intrastriatal injection of N-methyl-d-aspartate (NMDA). However, there appears to be no consistent correlation between increases in T1 relaxation and changes in other MRI parameters (apparent diffusion coefficient, T2 relaxation, or magnetisation transfer ratio of tissue water). Immunohistochemically, one common morphologic feature shared by the ET-1 and NMDA models is acute astrocyte activation, which was detectable within 2 h of intracerebral ET-1 injection. Pretreatment with an inhibitor of astrocyte activation, arundic acid, significantly reduced the spatial extent of the T1 signal change induced by intrastriatal ET-1 injection. These findings suggest that an increase in T1 relaxation may identify the acute development of reactive astrocytes within a central nervous system lesion. Early changes in T1 may, therefore, provide insight into acute and reversible injury processes in neurologic patients, such as those observed before contrast enhancement in MS.

scholarly journals Stroke Penumbra Defined by an MRI-Based Oxygen Challenge Technique: 2. Validation based on the Consequences of Reperfusion

2011 ◽  
Vol 31 (8) ◽  
pp. 1788-1798 ◽  
Author(s):  
Craig A Robertson ◽  
Christopher McCabe ◽  
Lindsay Gallagher ◽  
Maria del Rosario Lopez-Gonzalez ◽  
William M Holmes ◽  
...  
Keyword(s):  
Oxygen Extraction Fraction ◽  
Surrounding Tissue ◽  
Sprague Dawley ◽  
Extraction Fraction ◽  
Sprague Dawley Rats ◽  
Signal Change ◽  
Apparent Diffusion ◽  
Apparent Diffusion Coefficient Maps ◽  
Contralateral Cortex ◽  
Magnetic Resonance Imaging Mri

Magnetic resonance imaging (MRI) with oxygen challenge (T*2 OC) uses oxygen as a metabolic biotracer to define penumbral tissue based on CMRO2 and oxygen extraction fraction. Penumbra displays a greater T*2 signal change during OC than surrounding tissue. Since timely restoration of cerebral blood flow (CBF) should salvage penumbra, T*2 OC was tested by examining the consequences of reperfusion on T*2 OC-defined penumbra. Transient ischemia (109 ± 20 minutes) was induced in male Sprague-Dawley rats ( n = 8). Penumbra was identified on T*2-weighted MRI during OC. Ischemia and ischemic injury were identified on CBF and apparent diffusion coefficient maps, respectively. Reperfusion was induced and scans repeated. T2 for final infarct and T*2 OC were run on day 7. T*2 signal increase to OC was 3.4% in contralateral cortex and caudate nucleus and was unaffected by reperfusion. In OC-defined penumbra, T*2 signal increased by 8.4% ± 4.1% during ischemia and returned to 3.25% ± 0.8% following reperfusion. Ischemic core T*2 signal increase was 0.39% ± 0.47% during ischemia and 0.84% ± 1.8% on reperfusion. Penumbral CBF increased from 41.94 ± 13 to 116.5 ± 25 mL per 100 g per minute on reperfusion. On day 7, OC-defined penumbra gave a normal OC response and was located outside the infarct. T*2 OC-defined penumbra recovered when CBF was restored, providing further validation of the utility of T*2 OC for acute stroke management.

Neural-Cardiac Coupling in Threat-Evoked Anxiety

2005 ◽  
Vol 17 (6) ◽  
pp. 969-980 ◽  
Author(s):  
Kim M. Dalton ◽  
Ned H. Kalin ◽  
Thomas M. Grist ◽  
Richard J. Davidson
Keyword(s):  
Cardiac Contractility ◽  
Brain Regions ◽  
Generalized Anxiety ◽  
Resonance Imaging ◽  
Imaging Studies ◽  
Signal Change ◽  
Sympathetic Nervous ◽  
Magnetic Resonance Imaging Mri ◽  
The Brain ◽  
Threat Of Shock

Anxiety is a debilitating symptom of many psychiatric disorders including generalized anxiety disorder, mood disorders, schizophrenia, and autism. Anxiety involves changes in both central and peripheral biology, yet extant functional imaging studies have focused exclusively on the brain. Here we show, using functional brain and cardiac imaging in sequential brain and cardiac magnetic resonance imaging (MRI) sessions in response to cues that predict either threat (a possible shock) or safety (no possibility of shock), that MR signal change in the amygdala and the prefrontal and insula cortices predicts cardiac contractility to the threat of shock. Participants with greater MR signal change in these regions show increased cardiac contractility to the threat versus safety condition, a measure of the sympathetic nervous system contribution to the myocardium. These findings demonstrate robust neural-cardiac coupling during induced anxiety and indicate that individuals with greater activation in brain regions identified with aversive emotion show larger magnitude cardiac contractility increases to threat.

scholarly journals Transient Periictal Brain Imaging Abnormality in a Saudi Patient with Probable Celiac Disease Epilepsy and Occipital Calcification Syndrome

2019 ◽  
Vol 2019 ◽  
pp. 1-5
Author(s):  
Soha Khan ◽  
Asma AlNajjar ◽  
Abdullah Alquaydheb ◽  
Shahpar Nahrir
Keyword(s):  
Celiac Disease ◽  
Energy Demand ◽  
Brain Mri ◽  
Brain Magnetic Resonance Imaging ◽  
Resonance Imaging ◽  
Pump Failure ◽  
Mediterranean Countries ◽  
Apparent Diffusion ◽  
Magnetic Resonance Imaging Mri ◽  
The Brain

Celiac disease epilepsy and occipital calcification (CEC) syndrome is a rare, emerging disease first described in 1992. To date, fewer than 200 cases have been reported worldwide. CEC syndrome is generally thought to be a genetic, noninherited, and ethnically and geographically restricted disease in Mediterranean countries. However, we report the first ever case of probable CEC in a Saudi patient. Furthermore, the patient manifested a magnitude of brain magnetic resonance imaging (MRI) signal abnormalities during the periictal period which, to the best of our knowledge, has never been described in CEC. The brain MRI revealed diffusion-weighted imaging (DWI) restriction with a concordant area of apparent diffusion coefficient (ADC) hypointensity around bilateral occipital area of calcification. An imbalance between the heightened energy demand during ictal phase of the seizure and unadjusted blood supply may have caused an electric pump failure and cytotoxic edema, which then led to DWI/ADC signal alteration.

Delayed reduction of tissue water diffusion after myocardial ischemia

1998 ◽  
Vol 275 (2) ◽  
pp. H697-H702 ◽  
Author(s):  
Edward W. Hsu ◽  
Rong Xue ◽  
Alex Holmes ◽  
John R. Forder
Keyword(s):  
Myocardial Infarction ◽  
Myocardial Ischemia ◽  
Morphological Analysis ◽  
Tissue Water ◽  
Apparent Diffusion ◽  
Regional Myocardial Ischemia ◽  
Contrast Mechanism ◽  
Tissue Contrast ◽  
Affected Tissue ◽  
Magnetic Resonance Imaging Mri

The apparent diffusion coefficient (ADC) of water after regional myocardial ischemia was measured in isolated, perfused rabbit hearts by using magnetic resonance imaging (MRI) techniques. After ligation of the left anterior descending coronary artery, the ADC of the nonperfused region showed a gradual but significant decreasing trend over time, whereas that of the normally perfused myocardium remained constant. Morphological analysis revealed that the ADC decrease reflected the expansion of a subregion of reduced ADC within the nonperfused myocardium. The dynamics of the diffusion change and the morphological progression of the affected tissue suggest that the ADC decrease may be linked to the onset of myocardial infarction, which is known to involve myocyte swelling. The ADC reduction provides a potentially valuable MRI tissue-contrast mechanism for noninvasively determining the viability of the ischemic myocardium and assessing the dynamics of acute myocardial infarction.

Experimental Rodent Models of Vascular Dementia: A Systematic Review

2021 ◽  
Vol 19 ◽  
Author(s):  
Nidhi Tiwari ◽  
Jyoti Upadhyay ◽  
Mohd Nazam Ansari ◽  
Syed Shadab Raza ◽  
Wasim Ahmad ◽  
...  
Keyword(s):  
Vascular Dementia ◽  
Small Vessel Disease ◽  
Current Knowledge ◽  
Vascular Cognitive Impairment ◽  
Experimental Models ◽  
New Drugs ◽  
Amyloid Angiopathy ◽  
Vessel Disease ◽  
The Brain ◽  
Large Vessel Disease

: Vascular dementia (VaD) occurs due to cerebrovascular insufficiency, which leads to decreased blood circulation to the brain, thereby resulting in mental disabilities. The main causes of vascular cognitive impairment (VCI) are severe hypoperfusion, stroke, hypertension, large vessel disease (cortical), small vessel disease (subcortical VaD), strategic infarct, hemorrhage (microbleed), cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), and cerebral amyloid angiopathy (CAA),which leads to decreased cerebrovascular perfusion. Many metabolic disorders such as diabetes mellitus (DM), dyslipidemia, and hyperhomocysteinemia are also related to VaD. The rodent experimental models provide a better prospective for the investigation of the molecular mechanism of new drugs. A plethora of experimental models are available that mimic the pathological conditions and lead to VaD. This review article updates the current knowledge on the basis of VaD, risk factors, pathophysiology, mechanism, advantages, limitations, and the modification of various available rodent experimental models.

Bilateral Striatal Necrosis with Polyneuropathy with a Novel SLC25A19 (Mitochondrial Thiamine Pyrophosphate Carrier OMIMI*606521) Mutation: Treatable Thiamine Metabolic Disorder—A Report of Two Indian Cases

2019 ◽  
Vol 50 (05) ◽  
pp. 313-317 ◽  
Author(s):  
Vykuntaraju K. Gowda ◽  
Varunvenkat M. Srinivasan ◽  
Kapil Jehta ◽  
Maya D. Bhat
Keyword(s):  
Gene Mutations ◽  
Febrile Illness ◽  
Flaccid Paralysis ◽  
Thiamine Pyrophosphate ◽  
Homozygous Mutation ◽  
Missense Variation ◽  
Magnetic Resonance Imaging Mri ◽  
The Brain ◽  
Generation Sequencing ◽  
Striatal Necrosis

Abstract Background SLC25A19 gene mutations cause Amish congenital lethal microcephaly and bilateral striatal necrosis with polyneuropathy. We are reporting two cases of bilateral striatal necrosis with polyneuropathy due to SLC25A19 gene mutations. Methods A 36-month-old boy and a 5-year-old girl, unrelated, presented with recurrent episodes of flaccid paralysis and encephalopathy following nonspecific febrile illness. Examination showed dystonia and absent deep tendon reflexes. Results Nerve conduction studies showed an axonal polyneuropathy. Magnetic resonance imaging (MRI) of the brain in both cases showed signal changes in the basal ganglia. Next-generation sequencing revealed a novel homozygous missense variation c.910G>A (p.Glu304Lys) in the SLC25A19 gene in the boy and a homozygous mutation c.869T > A (p. Leu290Gln) in the SLC25A19 gene in the girl. Mutations were validated by Sanger sequencing, and carrier statuses of parents of both children were confirmed. Both children improved with thiamine supplementation. Conclusion If any child presents with recurrent encephalopathy with flaccid paralysis, dystonia, and neuropathy, a diagnosis of bilateral striatal necrosis with polyneuropathy due to SLC25A19 mutations should be considered and thiamine should be initiated.

scholarly journals Beyond Oncological Hyperthermia: Physically Drivable Magnetic Nanobubbles as Novel Multipurpose Theranostic Carriers in the Central Nervous System

Molecules ◽  
2020 ◽  
Vol 25 (9) ◽  
pp. 2104 ◽  
Author(s):  
Eleonora Ficiarà ◽  
Shoeb Anwar Ansari ◽  
Monica Argenziano ◽  
Luigi Cangemi ◽  
Chiara Monge ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Brain Tumors ◽  
Ad Hoc ◽  
Superparamagnetic Iron Oxide ◽  
Conventional Radiotherapy ◽  
The Central Nervous System ◽  
Magnetic Resonance Imaging Mri ◽  
The Brain

Magnetic Oxygen-Loaded Nanobubbles (MOLNBs), manufactured by adding Superparamagnetic Iron Oxide Nanoparticles (SPIONs) on the surface of polymeric nanobubbles, are investigated as theranostic carriers for delivering oxygen and chemotherapy to brain tumors. Physicochemical and cyto-toxicological properties and in vitro internalization by human brain microvascular endothelial cells as well as the motion of MOLNBs in a static magnetic field were investigated. MOLNBs are safe oxygen-loaded vectors able to overcome the brain membranes and drivable through the Central Nervous System (CNS) to deliver their cargoes to specific sites of interest. In addition, MOLNBs are monitorable either via Magnetic Resonance Imaging (MRI) or Ultrasound (US) sonography. MOLNBs can find application in targeting brain tumors since they can enhance conventional radiotherapy and deliver chemotherapy being driven by ad hoc tailored magnetic fields under MRI and/or US monitoring.

scholarly journals Sotalol does not interfere with the antielectroshock action of selected second-generation antiepileptic drugs in mice

2021 ◽  
Author(s):  
Kinga K. Borowicz-Reutt ◽  
Monika Banach ◽  
Monika Rudkowska ◽  
Anna Stachniuk
Keyword(s):  
Antiepileptic Drugs ◽  
Second Generation ◽  
Antidepressant Drug ◽  
Experimental Models ◽  
Long Term Memory ◽  
Avoidance Task ◽  
Maximal Electroshock ◽  
Term Memory ◽  
The Brain

Abstract Background Due to blocking β-receptors, and potassium KCNH2 channels, sotalol may influence seizure phenomena. In the previous study, we have shown that sotalol potentiated the antielectroshock action of phenytoin and valproate in mice. Materials and methods As a continuation of previous experiments, we examined the effect of sotalol on the action of four chosen second-generation antiepileptic drugs (oxcarbazepine, lamotrigine, pregabalin, and topiramate) against the maximal electroshock in mice. Undesired effects were evaluated in the chimney test (motor impairment) and step-through passive-avoidance task (long-term memory deficits). Finally, brain concentrations of antiepileptics were determined by fluorescence polarization immunoassay, while those of sotalol by liquid chromatography–mass spectrometry. Results Sotalol at doses of up to 100 mg/kg did not affect the electroconvulsive threshold. Applied at doses of 80–100 mg/kg, sotalol did not affect the antielectroshock action of oxcarbazepine, lamotrigine, pregabalin, or topiramate. Sotalol alone and in combinations with antiepileptics impaired neither motor performance nor long-term memory. Finally, sotalol significantly decreased the brain concentrations of lamotrigine and increased those of oxcarbazepine and topiramate. Pharmacokinetic interactions, however, did not influence the final antielectroshock effects of above-mentioned drug combinations. On the other hand, the brain concentrations of sotalol were not changed by second-generation antiepileptics used in this study. Conclusion Sotalol did not reduce the antielectroshock action of four second-generation antiepileptic drugs examined in this study. Therefore, this antidepressant drug should not interfere with antiseizure effects of lamotrigine, oxcarbazepine, pregabalin, and topiramate in patients with epilepsy. To draw final conclusions, our preclinical data should still be confirmed in other experimental models and clinical conditions.

scholarly journals An improved framework for brain tumor analysis using MRI based on YOLOv2 and convolutional neural network

2021 ◽  
Author(s):  
Muhammad Irfan Sharif ◽  
Jian Ping Li ◽  
Javeria Amin ◽  
Abida Sharif
Keyword(s):  
Brain Tumor ◽  
Tumor Detection ◽  
Entropy Method ◽  
Feature Extraction And Selection ◽  
Tumor Region ◽  
Selection For ◽  
Magnetic Resonance Imaging Mri ◽  
The Brain ◽  
Complicated Task

AbstractBrain tumor is a group of anomalous cells. The brain is enclosed in a more rigid skull. The abnormal cell grows and initiates a tumor. Detection of tumor is a complicated task due to irregular tumor shape. The proposed technique contains four phases, which are lesion enhancement, feature extraction and selection for classification, localization, and segmentation. The magnetic resonance imaging (MRI) images are noisy due to certain factors, such as image acquisition, and fluctuation in magnetic field coil. Therefore, a homomorphic wavelet filer is used for noise reduction. Later, extracted features from inceptionv3 pre-trained model and informative features are selected using a non-dominated sorted genetic algorithm (NSGA). The optimized features are forwarded for classification after which tumor slices are passed to YOLOv2-inceptionv3 model designed for the localization of tumor region such that features are extracted from depth-concatenation (mixed-4) layer of inceptionv3 model and supplied to YOLOv2. The localized images are passed toMcCulloch'sKapur entropy method to segment actual tumor region. Finally, the proposed technique is validated on three benchmark databases BRATS 2018, BRATS 2019, and BRATS 2020 for tumor detection. The proposed method achieved greater than 0.90 prediction scores in localization, segmentation and classification of brain lesions. Moreover, classification and segmentation outcomes are superior as compared to existing methods.

scholarly journals Cinematic rendering of a burst sagittal suture caused by an occipito-frontal gunshot wound

2021 ◽  
Author(s):  
Dominic Gascho ◽  
Michael J. Thali ◽  
Rosa M. Martinez ◽  
Stephan A. Bolliger
Keyword(s):  
Gunshot Wound ◽  
Three Dimensional ◽  
The Novel ◽  
Sagittal Suture ◽  
Resonance Imaging ◽  
Cinematic Rendering ◽  
Reconstruction Methods ◽  
Dimensional Reconstruction ◽  
Magnetic Resonance Imaging Mri ◽  
The Brain

AbstractThe computed tomography (CT) scan of a 19-year-old man who died from an occipito-frontal gunshot wound presented an impressive radiating fracture line where the entire sagittal suture burst due to the high intracranial pressure that arose from a near-contact shot from a 9 mm bullet fired from a Glock 17 pistol. Photorealistic depictions of the radiating fracture lines along the cranial bones were created using three-dimensional reconstruction methods, such as the novel cinematic rendering technique that simulates the propagation and interaction of light when it passes through volumetric data. Since the brain had collapsed, depiction of soft tissue was insufficient on CT images. An additional magnetic resonance imaging (MRI) examination was performed, which enabled the diagnostic assessment of cerebral injuries.

Sign in / Sign up

Export Citation Format

Share Document