Advances in MRI Methodology

Yousaf, Tayyabah; Dervenoulas, George; Politis, Marios

doi:10.1016/bs.irn.2018.08.008

Cited by 166 publications

(103 citation statements)

References 161 publications

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“…Paramagnetic contrast agents alter the appearance of an image typically by shortening the T 1 or T 2 of water protons. Although Gd 3+ -based agents are typically referred to T 1 agents because they have the biggest impact on the T 1 of water protons, they certainly impact both T 1 and T 2 [ 1 ]. Although complexes of other paramagnetic ions, including Mn 2+ , Mn 3+ , Fe 3+ , and Cu 2+ , have been proposed as MRI contrast agents, they each impact water proton relaxation and hence image contrast through somewhat different mechanisms.…”

Section: Detection Of Zinc With Magnetic Resonance Imagingmentioning

confidence: 99%

“…Magnetic resonance imaging (MRI) is now widely accepted as one of the most important diagnostic imaging tools available to clinicians because it is non-invasive, widely available, and provides anatomical images with high spatial and temporal resolution [ 1 ]. Since its first introduction into clinical medicine in the 1970s, MRI has improved significantly, mostly due to improvements in radio-frequency transmitters and receivers, gradient systems, faster computers, and post-processing software [ 2 ].…”

Section: Introductionmentioning

confidence: 99%

“…Paramagnetic metal ion complexes, mostly based on gadolinium, have been used as MRI contrast agents since the first agent appeared on the market in 1986 [ 4 ]. The different signal intensities seen as grayscale intensity differences in MR images reflect differences in water and fat content in various tissues and the relaxation characteristics of those water, fat, and other protons, specifically their T 1 and T 2 relaxation times [ 1 ]. The influence of paramagnetic complexes on water proton relaxation can be rather dramatic depending upon the concentration of the agent.…”

Section: Introductionmentioning

confidence: 99%

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Imaging Tissue Physiology In Vivo by Use of Metal Ion-Responsive MRI Contrast Agents

2020

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Paramagnetic metal ion complexes, mostly based on gadolinium (Gd3+), have been used for over 30 years as magnetic resonance imaging (MRI) contrast agents. Gd3+-based contrast agents have a strong influence on T1 relaxation times and are consequently the most commonly used agents in both the clinical and research environments. Zinc is an essential element involved with over 3000 different cellular proteins, and disturbances in tissue levels of zinc have been linked to a wide range of pathologies, including Alzheimer’s disease, prostate cancer, and diabetes mellitus. MR contrast agents that respond to the presence of Zn2+ in vivo offer the possibility of imaging changes in Zn2+ levels in real-time with the superior spatial resolution offered by MRI. Such responsive agents, often referred to as smart agents, are typically composed of a paramagnetic metal ion with a ligand encapsulating it and one or more chelating units that selectively bind with the analyte of interest. Translation of these agents into clinical radiology is the next goal. In this review, we discuss Gd3+-based MR contrast agents that respond to a change in local Zn2+ concentration.

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Section: Detection Of Zinc With Magnetic Resonance Imagingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Imaging Tissue Physiology In Vivo by Use of Metal Ion-Responsive MRI Contrast Agents

2020

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“…Magnetic resonance imaging is a noninvasive imaging technique that can provide multiparametric and comprehensive information [ 7 ]. In 1980s, magnetic resonance imaging was introduced, and it revolutionized modern medical imaging technology.…”

Section: Medical Imagingmentioning

confidence: 99%

Application of Nanomaterials in Biomedical Imaging and Cancer Therapy

2020

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Nanomaterials, such as nanoparticles, nanorods, nanosphere, nanoshells, and nanostars, are very commonly used in biomedical imaging and cancer therapy. They make excellent drug carriers, imaging contrast agents, photothermal agents, photoacoustic agents, and radiation dose enhancers, among other applications. Recent advances in nanotechnology have led to the use of nanomaterials in many areas of functional imaging, cancer therapy, and synergistic combinational platforms. This review will systematically explore various applications of nanomaterials in biomedical imaging and cancer therapy. The medical imaging modalities include magnetic resonance imaging, computed tomography, positron emission tomography, single photon emission computerized tomography, optical imaging, ultrasound, and photoacoustic imaging. Various cancer therapeutic methods will also be included, including photothermal therapy, photodynamic therapy, chemotherapy, and immunotherapy. This review also covers theranostics, which use the same agent in diagnosis and therapy. This includes recent advances in multimodality imaging, image-guided therapy, and combination therapy. We found that the continuous advances of synthesis and design of novel nanomaterials will enhance the future development of medical imaging and cancer therapy. However, more resources should be available to examine side effects and cell toxicity when using nanomaterials in humans.

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“…6 MRI is a technique that provides advanced and comprehensive brain information, including structural anatomy of the brain as well as information on how it functions, in a harmless and non-invasive manner. 8 Recently, a more burgeoning and accurate technique has arisen called functional magnetic resonance imaging (fMRI), which compensates for the limitations of MRI by providing information on the activity level of specific parts of the cerebral cortex. 9 One branch of fMRI is BOLD-fMRI (blood oxygenation level-dependent functional MRI), which can detect spontaneous fluctuations of the BOLD-fMRI signal in a resting state, which is detected by ALFF (amplitude of lowfrequency fluctuation).…”

Section: Introductionmentioning

confidence: 99%

<p>Altered Spontaneous Brain Activity Patterns in Patients After Lasik Surgery Using Amplitude of Low-Frequency Fluctuation: A Resting-State Functional MRI Study</p>

Yan¹,

Liang²,

Yang³

et al. 2020

NDT

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Previous studies demonstrated that myopia could result in alterations of brain activity in specific areas. However, whether the visual function could improve by Lasik surgery, with the brain activity alterations also change, is still unknown. Here, we intended to use the amplitude of low-frequency fluctuation (ALFF) technique to investigate the intrinsic brain activity changes in pre-Lasik (PRL) and post-Lasik (POL) patients. Methods: A total of 15 patients with myopia (nine male and six female) were recruited in our study, who were matched according to age, weight, and height. These patients comprised both the PRL and POL groups, which is self-controlled. The patients all underwent resting-state functional magnetic resonance imaging (MRI), and the spontaneous brain activity changes were recorded by the ALFF technique. The data were recorded and arranged in the receiver operating characteristic (ROC) curve, which presented how intrinsic activities altered in different brain regions. Moreover, by Graphpad prism 8, we can analyze the linear correlation between HADS (Hospital Anxiety and Depression Scale) and ALFF values as well. Results: Differences in ALFF values existed in brain regions between the same patient before and after the Lasik operation. The regions with increased ALFF values after Lasik surgery were the left parahippocampal gyrus, cerebellar vermis, and left posterior cingulate cortex. The regions with decreased ALFF values after Lasik surgery were the left supramarginal gyrus and right trigonometric inferior frontal gyrus. Conclusion: We demonstrated significant fluctuations of ALFF values in specific brain areas between the same patients before and after the Lasik surgery. The altered ALFF values reflected the hyperactivity or hypoactivity of the specific brain areas, which may help predict the recovery level of patients' vision after Lasik surgery. Furthermore, based on the experimental results that presented significant activity alterations in specific brian regions, patients could be speculated equipped with a better visual function.

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Advances in MRI Methodology

Cited by 166 publications

References 161 publications

Imaging Tissue Physiology In Vivo by Use of Metal Ion-Responsive MRI Contrast Agents

Imaging Tissue Physiology In Vivo by Use of Metal Ion-Responsive MRI Contrast Agents

Application of Nanomaterials in Biomedical Imaging and Cancer Therapy

<p>Altered Spontaneous Brain Activity Patterns in Patients After Lasik Surgery Using Amplitude of Low-Frequency Fluctuation: A Resting-State Functional MRI Study</p>

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