Multiplication of acquired MR data by a function smoothly tapering off at higher spatial frequencies so as to reduce ringing artifacts near edges in the corresponding image or spectrum due to truncation and Gibbs phenomenon. It is a form of filtering.
Searchterm 'Spectrum' was also found in the following services:
Controlling the frequencyspectrum (bandwidth) of a RF pulse (via tailoring) while imposing a magnetic field gradient on spins, such that only a desired region will have an appropriate resonant frequency to be excited.
Originally used to excite all but a desired region; now often used to select only a desired region, such as a plane, for excitation. Used without simultaneous magnetic field gradients, tailored RF pulses can be used to selectively excite a particular spectral line or group of lines. RF and gradient pulse combinations can be designed to select both spatial regions and spectral frequencies.
(SVS) This method maps the metabolic information from the VOI in a spectrum. Single volume techniques are advantageous in case of pathological changes that cannot spatially be limited to a few VOI; by using local volume sensitive shim the local magnetic fieldinhomogeneity can be compensated.
Plural of spectrum. Spectra are components of the MR signal according to frequencies. Spectroscopy uses NMR spectral components to identify the metabolites, e.g. of the brain.
The overall width in hertz needed to observe a particular NMRspectrum. This width is generally set using the Nyquist limit; namely, that the temporal sampling rate must be equal to twice the maximum spread in frequencies.