scholarly journals A piglet model for detection of hypoxic-ischemic brain injury with magnetic resonance imaging

2008 ◽  
Vol 49 (9) ◽  
pp. 1049-1057 ◽  
Author(s):  
B. H. Munkeby ◽  
C. De Lange ◽  
K. E. Emblem ◽  
A. Bjørnerud ◽  
G. A. B. Kro ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Basal Ganglia ◽  
Magnetic Resonance ◽  
Diffusion Tensor ◽  
Therapeutic Interventions ◽  
Resonance Imaging ◽  
Prognostic Information ◽  
Proton Mrs ◽  
Apparent Diffusion ◽  
Magnetic Resonance Imaging Mri

Background: Early detection of hypoxic-ischemic (HI) injury in the asphyxic newborn is important because present prognostic factors are inadequate. Furthermore, therapeutic interventions may have additional benefit if initiated in time. Purpose: To assess whether the use of a combined protocol including conventional magnetic resonance imaging (MRI), diffusion-weighted imaging (DWI), diffusion tensor imaging (DTI), and proton MR spectroscopy (MRS) could detect pathological findings in a piglet model 7 hours after HI. Material and Methods: Ten piglets were submitted to HI for 30 min followed by reoxygenation with 21% O2 for 7 hours. MRI at 1.5T was done prior to and 7 hours after the HI. Single-voxel proton MRS was performed, and apparent diffusion coefficient (ADC) and fractional anisotropy (FA) were measured in the basal ganglia. MRS identified N-acetylaspartate (NAA), choline (Cho), creatine (Cr), and lactate (Lac). Histology and microtubule-associated protein 2 (MAP-2) staining was performed in the basal ganglia at the end of the experiment. Results: Compared to baseline, ADC, NAA/Cho, and NAA/Cr were significantly reduced after 7 hours ( P<0.001, P=0.01, and P=0.05, respectively) and FA values were increased ( P<0.025). The ratios of Lac/Cho and Lac/NAA were significantly higher after 7 hours compared to baseline ( P<0.001). Presence of necrosis correlated well with reduced ADC ( RS=0.91) and presence of Lac ( RS=0.80). Histology and MAP-2 staining showed more than 90% necrosis in eight piglets, 60% in one piglet, and no necrosis in one piglet. Conclusion: Diffusion MRI and proton MRS can detect HI injury in the piglet brain 7 hours after hypoxia. DWI and MRS can be used to give useful prognostic information. This piglet model may potentially be used to mimic clinical situations and is suitable for further research investigating HI injury.

scholarly journals Magnetic Resonance Imaging in Animal Models of Alzheimer’s Disease Amyloidosis

2021 ◽  
Author(s):  
Ruiqing Ni
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Animal Models ◽  
Amyloid Beta ◽  
High Field ◽  
Diffusion Tensor ◽  
Small Animal ◽  
Resonance Imaging ◽  
Magnetic Resonance Imaging Mri

Amyloid-beta plays an important role in the pathogenesis of Alzheimer&rsquo;s disease. Aberrant amyloid-beta and tau accumulation induce neuroinflammation, cerebrovascular alterations, synaptic deficits, functional deficits, and neurodegeneration, leading to cognitive impairment. Animal models recapitulating the amyloid-beta pathology such as transgenic, knock-in mouse and rat models have facilitated the understanding of disease mechanisms and development of therapeutics targeting at amyloid-beta. There is a rapid advance in high-field MR in small animals. Versatile high-field magnetic resonance imaging (MRI) sequences such as diffusion tensor imaging, arterial spin labelling, resting-state functional MRI, anatomical MRI, MR spectroscopy as well as contrast agents have been developed for the applications in animal models. These tools have enabled high-resolution in vivo structural, functional, and molecular readouts with a whole brain field-of-view. MRI have been utilized to visualize non-invasively the amyloid-beta deposits, synaptic deficits, regional brain atrophy, impairment in white matter integrity, functional connectivity, cerebrovascular and glymphatic system in animal models of amyloidosis. Many of the readouts are translational in clinical MRI in the brain of patients with Alzheimer&rsquo;s disease. In this review, we summarize the recent advance of using MRI for visualizing the pathophysiology in amyloidosis animal model. We discuss the outstanding challenges in brain imaging using MRI in small animal and propose future outlook in visualizing amyloid-beta-related alterations in brain of animal models.

Magnetic Resonance Imaging and Ultrasound-Guided Percutaneous Interventional Radiology Procedures

2018 ◽  
Author(s):  
Sharath K. Bhagavatula ◽  
Bijal Patel ◽  
Kemal Tuncali ◽  
Stuart G. Silverman ◽  
Paul B. Shyn
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Interventional Procedures ◽  
Therapeutic Interventions ◽  
Resonance Imaging ◽  
Invasive Procedures ◽  
Us Guidance ◽  
Clinical Considerations ◽  
Magnetic Resonance Imaging Mri ◽  
Interventional Radiology Procedures

Diagnostic and therapeutic interventions guided by magnetic resonance imaging (MRI) are performed in clinical practice with increasing frequency and for an increasing number of indications. Ultrasound (US) guidance remains a very common, relatively inexpensive, and versatile option for guiding percutaneous interventions. The need for procedural sedation and anesthesia for minimally invasive procedures continues to grow as the number of procedures and interventional applications increase. This trend will continue as the population ages and the complexity and array of imaging-guided interventional procedures expand. This chapter discusses common interventional procedures that are performed under MRI and US guidance and outlines patient issues, procedural techniques, safety, and other clinical considerations that pertain to both interventionalists and anesthesiologists.

scholarly journals Histological validation of myocardial microstructure obtained from diffusion tensor magnetic resonance imaging

1998 ◽  
Vol 275 (6) ◽  
pp. H2308-H2318 ◽  
Author(s):  
D. F. Scollan ◽  
Alex Holmes ◽  
Raimond Winslow ◽  
John Forder
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Diffusion Tensor ◽  
Ventricular Myocardium ◽  
Resonance Imaging ◽  
Anatomic Structure ◽  
Single Location ◽  
Quantitative Validation ◽  
Magnetic Resonance Imaging Mri ◽  
Histological Validation

Diffusion tensor magnetic resonance imaging (MRI) is a possible new means of elucidating the anatomic structure of the myocardium. It enjoys several advantages over traditional histological approaches, including the ability to rapidly measure fiber organization in isolated, perfused, arrested hearts, thereby avoiding fixation and sectioning of artifacts. However, quantitative validation of this MRI method has been lacking. Here, fiber orientations estimated in the same locations in the same heart using both diffusion tensor MRI and histology are compared in a total of two perfused rabbit hearts. Fiber orientations were statistically similar for both methods and differed on average by 12° at any single location. This is similar to the 10° uncertainty in fiber orientation achieved with histology. In addition, imaging studies performed in a total of seven hearts support a level of organization beyond the myofiber, the recently described laminar organization of the ventricular myocardium.

scholarly journals Two-kidney one-clip is a pertinent approach to integrate arterial hypertension in animal models of stroke: Serial magnetic resonance imaging studies of brain lesions before and during cerebral ischemia

2017 ◽  
Vol 38 (10) ◽  
pp. 1769-1780 ◽  
Author(s):  
Benjamin Ménard ◽  
Laurent Chazalviel ◽  
Simon Roussel ◽  
Myriam Bernaudin ◽  
Omar Touzani
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Arterial Hypertension ◽  
Brain Lesions ◽  
Cortical Lesions ◽  
Resonance Imaging ◽  
Spontaneously Hypertensive ◽  
Apparent Diffusion ◽  
Adc Values ◽  
Magnetic Resonance Imaging Mri

Although chronic arterial hypertension (CAH) represents the major comorbid factor in stroke, it is rarely integrated in preclinical studies of stroke. The majority of those investigations employ spontaneously hypertensive rats (SHR) which display a susceptibility to ischemic damage independent of hypertension. Here, we used a renovascular model of hypertension (RH) to examine, with magnetic resonance imaging (MRI), brain alterations during the development of hypertension and after brain ischemia. We also examined whether MRI-derived parameters predict the extent of ischemia-induced brain damage. RH was induced according to the two-kidney one-clip model and multiparametric MRI was performed at 3, 6, 9, and 12 weeks after hypertension and also at 10, 50, and 60 min following stroke. Blood pressure values increased progressively and reached a plateau at 6 weeks after RH induction. At 12 weeks, all hypertensive animals displayed spontaneous brain lesions (hemorrhages, deep and cortical lesions, ventricular dilatation), increased apparent diffusion coefficient (ADC) values in the corpus callosum and higher fractional anisotropy in the cortex. Following ischemia, these animals showed larger brain lesions (406 ± 82 vs. 179 ± 36 mm3, p < 0.002) which correlated with ADC values at chronic stage of hypertension. This model of hypertension displays many characteristics of the neuropathology of human CAH. The use of this model in stroke studies is relevant and desirable.

Quantitative magnetic resonance imaging for focal liver lesions: bridging the gap between research and clinical practice

2021 ◽  
pp. 20210220
Author(s):  
Roberto Cannella ◽  
Riccardo Sartoris ◽  
Jules Grégory ◽  
Lorenzo Garzelli ◽  
Valérie Vilgrain ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Clinical Practice ◽  
Magnetic Resonance ◽  
Quantitative Mri ◽  
Focal Liver Lesions ◽  
Liver Lesions ◽  
Resonance Imaging ◽  
Apparent Diffusion ◽  
Magnetic Resonance Imaging Mri ◽  
Diagnostic Work

Magnetic resonance imaging (MRI) is highly important for the detection, characterization, and follow-up of focal liver lesions. Several quantitative MRI-based methods have been proposed in addition to qualitative imaging interpretation to improve the diagnostic work-up and prognostics in patients with focal liver lesions. This includes DWI with apparent diffusion coefficient measurements, intravoxel incoherent motion, perfusion imaging, MR elastography, and radiomics. Multiple research studies have reported promising results with quantitative MRI methods in various clinical settings. Nevertheless, applications in everyday clinical practice are limited. This review describes the basic principles of quantitative MRI-based techniques and discusses the main current applications and limitations for the assessment of focal liver lesions.

Magnetic resonance imaging methods in developmental science: A primer

2008 ◽  
Vol 20 (4) ◽  
pp. 1029-1051 ◽  
Author(s):  
Ruskin H. Hunt ◽  
Kathleen M. Thomas
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Diffusion Tensor ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Resonance Signal ◽  
Primary Interest ◽  
Magnetic Resonance Imaging Mri ◽  
Effective Use ◽  
Design Factors

AbstractStructural and functional magnetic resonance imaging (MRI) are increasingly common research methods among investigators interested in typically and atypically developing populations. However, the effective use of these tools requires an understanding of the basis of the magnetic resonance signal, as well as some of the additional experimental complications that arise when collecting MRI data from developmental populations. This primer provides a foundation for investigators who wish to utilize MRI methods in their research and whose primary interest involves typically and atypically developing populations. The basic concepts of MRI physics are introduced, as well as the typical MRI scanner components and their role in MRI data acquisition. In addition, a variety of scan types (structural, functional, diffusion tensor) are discussed, along with a number of important experimental design factors that can impact the quality and utility of the data collected. Special consideration is given to working with pediatric and special populations.

scholarly journals Magnetic ressonance imaging in the diagnosis of Creutzfeldt-Jakob disease: report of two cases

2015 ◽  
Vol 9 (4) ◽  
pp. 424-427
Author(s):  
Alan Peres Valente ◽  
Paula da Cunha Pinho ◽  
Leandro Tavares Lucato
Keyword(s):  
Magnetic Resonance Imaging ◽  
Basal Ganglia ◽  
Magnetic Resonance ◽  
Clinical Presentation ◽  
Rare Condition ◽  
Resonance Imaging ◽  
Progressive Dementia ◽  
Jakob Disease ◽  
Magnetic Resonance Imaging Mri ◽  
Aids Diagnosis

ABSTRACT Creutzfeldt-Jacob disease (CJD) is a rare condition caused by a pathogenic prion protein that evolves with rapidly progressive dementia and death. The clinical presentation may sometimes be misleading. Magnetic Resonance Imaging (MRI) aids diagnosis with patterns that can guide or confirm clinical hypotheses. Two cases of rapidly progressive dementia with ataxia, myoclonus and restricted diffusion on MRI in cortical/basal ganglia are presented to draw attention to CJD.

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