Search results
Results From The WOW.Com Content Network
T2*-weighted imaging of the brain 26 weeks after subarachnoid hemorrhage, showing hemosiderin deposits as hypointense areas. [1] T 2 *-weighted imaging is an MRI sequence to quantify observable or effective T 2 (T2* or "T2-star"). In this sequence, hemorrhages and hemosiderin deposits become hypointense. [2]
There are three main methods of manipulating contrast at this stage, namely steady-state free-precession (SSFP) that does not spoil the remaining transverse magnetisation, but attempts to recover them (thus producing T2-weighted images); the sequence with spoiler gradient that averages the transverse magnetisations (thus producing mixed T1 and ...
At the end, images are "weighted" by the diffusion process: In those diffusion-weighted images (DWI) the signal is more attenuated the faster the diffusion and the larger the b factor is. However, those diffusion-weighted images are still also sensitive to T1 and T2 relaxivity contrast, which can sometimes be confusing.
T1 weighted: T1: Measuring spin–lattice relaxation by using a short repetition time (TR) and echo time (TE). Lower signal for more water content, [67] as in edema, tumor, infarction, inflammation, infection, hyperacute or chronic hemorrhage. [68] High signal for fat [67] [68] High signal for paramagnetic substances, such as MRI contrast ...
T1 weighted: T1: Measuring spin–lattice relaxation by using a short repetition time (TR) and echo time (TE). Lower signal for more water content, [1] as in edema, tumor, infarction, inflammation, infection, hyperacute or chronic hemorrhage. [2] High signal for fat [1] [2] High signal for paramagnetic substances, such as MRI contrast agents [2]
This axial T2-weighted (CSF white) MR scan shows a normal brain at the level of the lateral ventricles. The record for the highest spatial resolution of a whole intact brain (postmortem) is 100 microns, from Massachusetts General Hospital. The data was published in Scientific Data on 30 October 2019. [17] [18]
In Dynamic susceptibility contrast MR imaging (DSC-MRI, or simply DSC), Gadolinium contrast agent (Gd) is injected (usually intravenously) and a time series of fast T2*-weighted images is acquired. As Gadolinium passes through the tissues, it induces a reduction of T2* in the nearby water protons; the corresponding decrease in signal intensity ...
Fluid-attenuated inversion recovery (FLAIR) [2] is an inversion-recovery pulse sequence used to nullify the signal from fluids. For example, it can be used in brain imaging to suppress cerebrospinal fluid so as to bring out periventricular hyperintense lesions, such as multiple sclerosis plaques.