Alzheimer's disease: The use of contrast agents for magnetic resonance imaging to detect amyloid beta peptide inside the brain

There are many kinds of brain abnormalities that cause changes in different parts of the brain. Alzheimer’s disease is a chronic condition that degenerates the cells of the brain leading to memory asthenia. Cognitive mental troubles such as forgetfulness and confusion are one of the most important features of Alzheimer’s patients. In the literature, several image processing techniques, as well as machine learning strategies, were introduced for the diagnosis of the disease. This study is aimed at recognizing the presence of Alzheimer’s disease based on the magnetic resonance imaging of the brain. We adopted a deep learning methodology for the discrimination between Alzheimer’s patients and healthy patients from 2D anatomical slices collected using magnetic resonance imaging. Most of the previous researches were based on the implementation of a 3D convolutional neural network, whereas we incorporated the usage of 2D slices as input to the convolutional neural network. The data set of this research was obtained from the OASIS website. We trained the convolutional neural network structure using the 2D slices to exhibit the deep network weightings that we named as the Alzheimer Network (AlzNet). The accuracy of our enhanced network was 99.30%. This work investigated the effects of many parameters on AlzNet, such as the number of layers, number of filters, and dropout rate. The results were interesting after using many performance metrics for evaluating the proposed AlzNet.

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Zinc Metalloproteinases and Amyloid Beta-Peptide Metabolism: The Positive Side of Proteolysis in Alzheimer's Disease

Biochemistry Research International ◽

10.1155/2011/721463 ◽

2011 ◽

Vol 2011 ◽

pp. 1-13 ◽

Cited By ~ 9

Author(s):

Mallory Gough ◽

Catherine Parr-Sturgess ◽

Edward Parkin

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Amyloid Beta ◽

Neuronal Death ◽

Amyloid Beta Peptide ◽

Positive Side ◽

Beta Peptide ◽

Peptide Metabolism ◽

The Brain

Alzheimer's disease is a neurodegenerative condition characterized by an accumulation of toxic amyloid beta- (A-)peptides in the brain causing progressive neuronal death. A-peptides are produced by aspartyl proteinase-mediated cleavage of the larger amyloid precursor protein (APP). In contrast to this detrimental “amyloidogenic” form of proteolysis, a range of zinc metalloproteinases can process APP via an alternative “nonamyloidogenic” pathway in which the protein is cleaved within its A region thereby precluding the formation of intact A-peptides. In addition, other members of the zinc metalloproteinase family can degrade preformed A-peptides. As such, the zinc metalloproteinases, collectively, are key to downregulating A generation and enhancing its degradation. It is the role of zinc metalloproteinases in this “positive side of proteolysis in Alzheimer's disease” that is discussed in the current paper.

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Easy Identification of Optimal Coronal Slice on Brain Magnetic Resonance Imaging to Measure Hippocampal Area in Alzheimer’s Disease Patients

BioMed Research International ◽

10.1155/2020/5894021 ◽

2020 ◽

Vol 2020 ◽

pp. 1-6

Author(s):

P. Zach ◽

A. Bartoš ◽

A. Lagutina ◽

Z. Wurst ◽

P. Gallina ◽

...

Keyword(s):

Magnetic Resonance Imaging ◽

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Magnetic Resonance ◽

Brain Magnetic Resonance Imaging ◽

Control Group ◽

Resonance Imaging ◽

Hippocampal Area ◽

Left And Right ◽

The Brain

Introduction. Measurement of an- hippocampal area or volume is useful in clinical practice as a supportive aid for diagnosis of Alzheimer’s disease. Since it is time-consuming and not simple, it is not being used very often. We present a simplified protocol for hippocampal atrophy evaluation based on a single optimal slice in Alzheimer’s disease. Methods. We defined a single optimal slice for hippocampal measurement on brain magnetic resonance imaging (MRI) at the plane where the amygdala disappears and only the hippocampus is present. We compared an absolute area and volume of the hippocampus on this optimal slice between 40 patients with Alzheimer disease and 40 age-, education- and gender-mateched elderly controls. Furthermore, we compared these results with those relative to the size of the brain or the skull: the area of the optimal slice normalized to the area of the brain at anterior commissure and the volume of the hippocampus normalized to the total intracranial volume. Results. Hippocampal areas on the single optimal slice and hippocampal volumes on the left and right in the control group were significantly higher than those in the AD group. Normalized hippocampal areas and volumes on the left and right in the control group were significantly higher compared to the AD group. Absolute hippocampal areas and volumes did not significantly differ from corresponding normalized hippocampal areas as well as normalized hippocampal volumes using comparisons of areas under the receiver operating characteristic curves. Conclusion. The hippocampal area on the well-defined optimal slice of brain MRI can reliably substitute a complicated measurement of the hippocampal volume. Surprisingly, brain or skull normalization of these variables does not add any incremental differentiation between Alzheimer disease patients and controls or give better results.

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Nanoparticles as contrast agents for the diagnosis of Alzheimer’s disease: a systematic review

Nanomedicine ◽

10.2217/nnm-2019-0316 ◽

2020 ◽

Vol 15 (7) ◽

pp. 725-743

Author(s):

Marina Ulanova ◽

Anne Poljak ◽

Wei Wen ◽

Andre Bongers ◽

Lucy Gloag ◽

...

Keyword(s):

Magnetic Resonance Imaging ◽

Systematic Review ◽

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Magnetic Resonance ◽

Contrast Agents ◽

Literature Search ◽

Resonance Imaging ◽

Magnetic Contrast Agents ◽

Comprehensive Literature Search

Nanoparticle (NP)-based magnetic contrast agents have opened the potential for MRI to be used for early diagnosis of Alzheimer’s disease (AD). This article aims to review the current progress of research in this field. A comprehensive literature search was performed based on PubMed, Medline, EMBASE, PsychINFO and Scopus databases using the following terms: ‘Alzheimer’s disease’ AND ‘nanoparticles’ AND ‘Magnetic Resonance Imaging.’ 33 studies were included that described the development and utility of various NPs for AD imaging, including their coating, functionalization, MRI relaxivity, toxicity and bioavailability. NPs show immense promise for neuroimaging, due to superior relaxivity and biocompatibility compared with currently available imaging agents. Consistent reporting is imperative for further progress in this field.

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