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The first MR images of a human brain were obtained in 1978 by two groups of researchers at EMI Laboratories led by Ian Robert Young and Hugh Clow. [1] In 1986, Charles L. Dumoulin and Howard R. Hart at General Electric developed MR angiography, [2] and Denis Le Bihan obtained the first images and later patented diffusion MRI. [3]
CT scans may be used to diagnose headaches when neuroimaging is indicated and MRI is not available, or in emergency settings when hemorrhage, stroke, or traumatic brain injury is suspected. [9] MRI (magnetic resonance imaging) provides more sensitivity in the evaluation of the cavernous sinus and the orbital apex. [8]
MRI is widely used in hospitals and clinics for medical diagnosis, staging and follow-up of disease. Compared to CT, MRI provides better contrast in images of soft tissues, e.g. in the brain or abdomen. However, it may be perceived as less comfortable by patients, due to the usually longer and louder measurements with the subject in a long ...
Nowadays, MRI has all but replaced myelography. [4] MRI is preferable because injection of contrast medium into the spinal canal is infrequently needed for better images. However, a CT myelogram may be useful for patients who cannot undergo MRI (e.g., those with pacemakers or cochlear implants). CT is preferred when MRI images are limited by ...
MRI without contrast agents is the imaging mode of choice for pre-surgical, in-utero diagnosis and evaluation of fetal tumors, primarily teratomas, facilitating open fetal surgery, other fetal interventions, and planning for procedures (such as the EXIT procedure) to safely deliver and treat babies whose defects would otherwise be fatal. [52] [53]
Unlike push-pull cannula, microdialysis and in vivo voltammetry, fMRS is a non-invasive method for studying dynamics of biochemistry in an activated brain. It is done without exposing subjects to ionizing radiation like it is done in positron emission tomography (PET) or single-photon emission computed tomography (SPECT) studies. fMRS gives a ...
Effect of contrast agent on images: Defect of the blood–brain barrier after stroke shown in MRI. T 1-weighted images, left image without, right image with contrast medium administration. Gadolinium(III) containing MRI contrast agents (often termed simply "gado" or "gad") are the most commonly used for enhancement of vessels in MR angiography ...
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.