Lecture

MRI Contrast Agents: Mechanisms and Applications

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Description

This lecture covers the mechanisms of MRI contrast agents, focusing on how relaxation times are shortened by relaxivity, and discusses the applications of contrast agents in imaging blood vessels, tumours, and inflammation. Examples of intracellular contrast agents, such as Mn-enhanced MRI, are also presented.

In MOOC

Fundamentals of Biomedical Imaging: Magnetic Resonance Imaging (MRI)

This physics course covers the physical principles of major in vivo bio-imaging modalities. This course will focus on magnetic resonance imaging, also known as an MRI. In the first part of the course, the dynamic of spins in a magnetic field is described, leading to the essential notions of magnetic resonance (MR), excitation and relaxation. We will also discuss the basic mechanisms of image reconstruction, MR spectroscopy and functional MRI. You will learn how existing physical principles transcend into bi

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Related concepts (32)

Magnetic resonance imaging

Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to form pictures of the anatomy and the physiological processes of the body. MRI scanners use strong magnetic fields, magnetic field gradients, and radio waves to generate images of the organs in the body. MRI does not involve X-rays or the use of ionizing radiation, which distinguishes it from computed tomography (CT) and positron emission tomography (PET) scans.

Spin–spin relaxation

In physics, the spin–spin relaxation is the mechanism by which Mxy, the transverse component of the magnetization vector, exponentially decays towards its equilibrium value in nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI). It is characterized by the spin–spin relaxation time, known as T2, a time constant characterizing the signal decay. It is named in contrast to T1, the spin–lattice relaxation time.

Contrast agent

A contrast agent (or contrast medium) is a substance used to increase the contrast of structures or fluids within the body in medical imaging. Contrast agents absorb or alter external electromagnetism or ultrasound, which is different from radiopharmaceuticals, which emit radiation themselves. In x-ray imaging, contrast agents enhance the radiodensity in a target tissue or structure. In magnetic resonance imaging, contrast agents shorten (or in some instances increase) the relaxation times of nuclei within body tissues in order to alter the contrast in the image.

Radiocontrast agent

Radiocontrast agents are substances used to enhance the visibility of internal structures in X-ray-based imaging techniques such as computed tomography (contrast CT), projectional radiography, and fluoroscopy. Radiocontrast agents are typically iodine, or more rarely barium sulfate. The contrast agents absorb external X-rays, resulting in decreased exposure on the X-ray detector. This is different from radiopharmaceuticals used in nuclear medicine which emit radiation.

Stem-cell therapy

Stem-cell therapy is the use of stem cells to treat or prevent a disease or condition. , the only established therapy using stem cells is hematopoietic stem cell transplantation. This usually takes the form of a bone-marrow transplantation, but the cells can also be derived from umbilical cord blood. Research is underway to develop various sources for stem cells as well as to apply stem-cell treatments for neurodegenerative diseases and conditions such as diabetes and heart disease.

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