Search results
Results from the WOW.Com Content Network
The key to Phase-contrast MRI (PC-MRI) is the use of a bipolar gradient. [4] A bipolar gradient has equal positive and negative magnitudes that are applied for the same time duration. The bipolar gradient in PC-MRI is put in a sequence after RF excitation but before data collection during the echo time of the generic MRI modality.
Functional magnetic resonance imaging or functional MRI (fMRI) measures brain activity by detecting changes associated with blood flow. [1] [2] This technique relies on the fact that cerebral blood flow and neuronal activation are coupled. When an area of the brain is in use, blood flow to that region also increases. [3]
Like in vivo MRS, fMRS can probe different nuclei, such as hydrogen (1 H) and carbon (13 C). The 1 H nucleus is the most sensitive and is most commonly used to measure metabolite concentrations and concentration dynamics, whereas 13 C is best suited for characterizing fluxes and pathways of brain metabolism.
In vivo magnetic resonance spectroscopy (MRS) is a specialized technique associated with magnetic resonance imaging (MRI). [1] [2]Magnetic resonance spectroscopy (MRS), also known as nuclear magnetic resonance (NMR) spectroscopy, is a non-invasive, ionizing-radiation-free analytical technique that has been used to study metabolic changes in brain tumors, strokes, seizure disorders, Alzheimer's ...
The first study of the human brain at 3.0 T was published in 1994, [13] and in 1998 at 8 T. [14] Studies of the human brain have been performed at 9.4 T (2006) [15] and up to 10.5 T (2019). [16] Paul Lauterbur and Sir Peter Mansfield were awarded the 2003 Nobel Prize in Physiology or Medicine for their discoveries concerning MRI.
All patients are reviewed for contraindications prior to MRI scanning. Medical devices and implants are categorized as MR Safe, MR Conditional or MR Unsafe: [6] MR-Safe – The device or implant is completely non-magnetic, non-electrically conductive, and non-RF reactive, eliminating all of the primary potential threats during an MRI procedure.
Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!
In cerebral infarction, the penumbra has decreased perfusion. [1] Another MRI sequence, diffusion weighted MRI, estimates the amount of tissue that is already necrotic, and the combination of those sequences can therefore be used to estimate the amount of brain tissue that is salvageable by thrombolysis and/or thrombectomy.