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. MRI is a medical application of nuclear magnetic resonance (NMR) which can also be used for imaging in other NMR applications, such as NMR spectroscopy.
A brain tumor occurs when abnormal cells form within the brain. There are two main types of tumors: malignant tumors and benign (non-cancerous) tumors. These can be further classified as primary tumors, which start within the brain, and secondary tumors, which most commonly have spread from tumors located outside the brain, known as brain metastasis tumors. All types of brain tumors may produce symptoms that vary depending on the size of the tumor and the part of the brain that is involved. Where symptoms exist, they may include headaches, seizures, problems with vision, vomiting and mental changes. Other symptoms may include difficulty walking, speaking, with sensations, or unconsciousness.
Paul Christian Lauterbur was an American chemist who shared the Nobel Prize in Physiology or Medicine in 2003 with Peter Mansfield for his work which made the development of magnetic resonance imaging (MRI) possible.
Hyperpolarization is the nuclear spin polarization of a material in a magnetic field far beyond thermal equilibrium conditions determined by the Boltzmann distribution. It can be applied to gases such as 129Xe and 3He, and small molecules where the polarization levels can be enhanced by a factor of 104-105 above thermal equilibrium levels. Hyperpolarized noble gases are typically used in magnetic resonance imaging (MRI) of the lungs. Hyperpolarized small molecules are typically used for in vivo metabolic imaging. For example, a hyperpolarized metabolite can be injected into animals or patients and the metabolic conversion can be tracked in real-time. Other applications include determining the function of the neutron spin-structures by scattering polarized electrons from a very polarized target (3He), surface interaction studies, and neutron polarizing experiments.
Raymond Vahan Damadian was an American physician, medical practitioner, and inventor of the first nuclear magnetic resonance (NMR) scanning machine.
In vivo magnetic resonance spectroscopy (MRS) is a specialized technique associated with magnetic resonance imaging (MRI).
Magnetic resonance spectroscopic imaging (MRSI) is a noninvasive imaging method that provides spectroscopic information in addition to the image that is generated by MRI alone.
Christopher J. Hardy is an American physicist and inventor of several magnetic resonance imaging (MRI) subsystem technologies for use in real time MRI and cardiac MR imaging and spectroscopy.
Functional magnetic resonance spectroscopy of the brain (fMRS) uses magnetic resonance imaging (MRI) to study brain metabolism during brain activation. The data generated by fMRS usually shows spectra of resonances, instead of a brain image, as with MRI. The area under peaks in the spectrum represents relative concentrations of metabolites.
Huntington Medical Research Institutes (HMRI) is an independent, nonprofit, applied medical research organization in Pasadena, California. The Institutes conduct laboratory and clinical work for the development of technology used in the diagnosis and treatment of disease. The Molecular Medicine programs, such as cancer genetics, molecular neurology, molecular pathology and tissue engineering, were conducted at the 99 North El Molino Avenue facility until April 2018. The Neural Engineering program is conducted at the 734 Fairmount Avenue building directly adjacent to Huntington Hospital. The Advanced Imaging Laboratory is located nearby at 10 Pico Street, as is the Liver Center at 660 South Fair Oaks Avenue. A new 35,000 square foot laboratory building for HMRI opened at 686 South Fair Oaks Avenue, Pasadena in April 2018. Programs in the new facility include neurolological and cardiovascular studies, as well as preeclampsia research.
Sodium MRI is a specialised magnetic resonance imaging technique that uses strong magnetic fields, magnetic field gradients, and radio waves to generate images of the distribution of sodium in the body, as opposed to more common forms of MRI that utilise protons present in water (1H-MRI). Like the proton, sodium is naturally abundant in the body, so can be imaged directly without the need for contrast agents or hyperpolarization. Furthermore, sodium ions play a role in important biological processes via their contribution to concentration and electrochemical gradients across cellular membranes, making it of interest as an imaging target in health and disease.
In the field of medicine, radiomics is a method that extracts a large number of features from medical images using data-characterisation algorithms. These features, termed radiomic features, have the potential to uncover tumoral patterns and characteristics that fail to be appreciated by the naked eye. The hypothesis of radiomics is that the distinctive imaging features between disease forms may be useful for predicting prognosis and therapeutic response for various cancer types, thus providing valuable information for personalized therapy. Radiomics emerged from the medical fields of radiology and oncology and is the most advanced in applications within these fields. However, the technique can be applied to any medical study where a pathological process can be imaged.
Hyperpolarized carbon-13 MRI is a functional medical imaging technique for probing perfusion and metabolism using injected substrates.
The history of magnetic resonance imaging (MRI) includes the work of many researchers who contributed to the discovery of nuclear magnetic resonance (NMR) and described the underlying physics of magnetic resonance imaging, starting early in the twentieth century. MR imaging was invented by Paul C. Lauterbur who developed a mechanism to encode spatial information into an NMR signal using magnetic field gradients in September 1971; he published the theory behind it in March 1973.
Nola M. Hylton is an American oncologist who is Professor of Radiology and Director of the Breast Imaging Research Group at the University of California, San Francisco. She pioneered the usage of magnetic resonance imaging for the detection, diagnosis, and staging of breast cancer by using MRIs to locate tumors and characterize the surrounding tissue.
Denis Le Bihan is a medical doctor, physicist, member of the Institut de France, member of the French Academy of Technologies and director since 2007 of NeuroSpin, an institution of the Atomic Energy and Alternative Energy Commission (CEA) in Saclay, dedicated to the study of the brain by magnetic resonance imaging (MRI) with a very high magnetic field. Denis Le Bihan has received international recognition for his outstanding work, introducing new imaging methods, particularly for the study of the human brain, as evidenced by the many international awards he has received, such as the Gold Medal of the International Society of Magnetic Resonance in Medicine (2001), the coveted Lounsbery Prize, the Louis D. Prize from the Institut de France, the prestigious Honda Prize (2012), the Louis-Jeantet Prize (2014), the Rhein Foundation Award (2021). His work has focused on the introduction, development and application of highly innovative methods, notably diffusion MRI.
R. Mark Henkelman is a Canadian biophysics researcher in the field of medical imaging, now retired, who was appointed as a Fellow of the Royal Society of Canada (2005) and the Order of Canada (2019) in recognition of his pioneering contributions to the field of magnetic resonance imaging.
Hyperpolarized 129Xe gas magnetic resonance imaging (MRI) is a medical imaging technique used to visualize the anatomy and physiology of body regions that are difficult to image with standard proton MRI. In particular, the lung, which lacks substantial density of protons, is particularly useful to be visualized with 129Xe gas MRI. This technique has promise as an early-detection technology for chronic lung diseases and imaging technique for processes and structures reliant on dissolved gases. 129Xe is a stable, naturally occurring isotope of xenon with 26.44% isotope abundance. It is one of two Xe isotopes, along with 131Xe, that has non-zero spin, which allows for magnetic resonance. 129Xe is used for MRI because its large electron cloud permits hyperpolarization and a wide range of chemical shifts. The hyperpolarization creates a large signal intensity, and the wide range of chemical shifts allows for identifying when the 129Xe associates with molecules like hemoglobin. 129Xe is preferred over 131Xe for MRI because 129Xe has spin 1/2, a longer T1, and 3.4 times larger gyromagnetic ratio (11.78 MHz/T).
Hyperpolarized gas MRI, also known as hyperpolarized helium-3 MRI or HPHe-3 MRI, is a medical imaging technique that uses hyperpolarized gases to improve the sensitivity and spatial resolution of magnetic resonance imaging (MRI). This technique has many potential applications in medicine, including the imaging of the lungs and other areas of the body with low tissue density.
Michael Albert Thomas is an Indian-American physicist, academic, and clinical researcher. He is a Professor-in-Residence of Radiological Sciences, and Psychiatry at the Geffen School of Medicine, University of California, Los Angeles (UCLA). He is most known for developing novel single voxel based 2D NMR techniques, multi-voxel 2D MRS techniques using hybrid Cartesian as well as non-Cartesian spatio-temporal encoding such as concentric ring, radial and rosette trajectories.
