pre-saturation

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pre-saturation

A specialised MRI technique that uses repeated radio frequency excitation of structures adjacent to the region of interest to reduce or eliminate phase-effect artefacts.
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Role of spectral presaturation attenuated inversion-recovery fat-suppressed T2-weighted MR imaging in active inflammatory bowel disease.
The medic on board the vessel carries out the mandatory presaturation medical check -- Al Omoud is good to go.
Spatial presaturation: a method for suppressing flow artifacts and improving depiction of vascular anatomy in MR imaging.
The [sup.1]H-NMR spectra were acquired at 300 K using a standard one-dimensional noesypr1D pulse sequence with water presaturation and a total spin-echo delay (2 n[tau]) of 100 ms.
Signals related to presaturation of water resonance in the range of 4.5 to 5.5 were also removed.
For [sup.1]H spectra, a 1D NOESY pulse sequence (noesypr1d) with water presaturation during the 2 sec relaxation delay and 100 ms mixing time was used, and 128 transients were collected into 16k data points with a spectral width of 6602.1 Hz (11 ppm) and an acquisition time of 2.48 sec.
To obtain a CEST image, a z-spectrum is first collected by applying a train of presaturation pulses across a range of resonance frequencies, typically [+ or -] 5-7 ppm with water set to 0 ppm, to identify all endogenous exchanging protons in a tissue of interest.
For the serum, a CPMG (Carr-Purcell-Meiboom-Gill) presaturation pulse sequence was used to control spectral line-broadening due to the presence of residual proteins.
The methanol-extracted, water-soluble metabolites were determined by NMR using the presaturation technique to suppress the water peaks; TSP was used as the internal standard, and deuterated water was used to lock the field.
Caption: FIGURE 1: MRI axial imaging of the pelvis and thighs using the SPIR (Spectral Presaturation with Inversion Recovery) hybrid fat suppression technique.
Imaging sequences included as shown in [Table 1]: (a) coronal oblique (parallel to the long axis of the sacrum) T1W-TSE with spectral presaturation with inversion recovery (SPIR), (b) coronal oblique T2-weighted (T2W) TSE, (c) STIR, and (d) DWI.
An axial three-dimensional high-resolution T1-weighted fast gradient echo fat-suppressed sequence (TE/TR 2.4/4.6 ms; inversion delay spectral presaturation attenuated by inversion recovery (SPAIR) 90 ms; flip angle 10; FOV 360x360 [mm.sup.2], acquired voxel size 0.9x0.9x2.5 [mm.sup.3], reconstructed voxel size 0.83x0.83x2.50 [mm.sup.3], total acquisition time 60 s) was performed before administration of the contrast agent, followed by repeat performance of this same sequence at 0, 1, 2, 3, 4, 5, and 7 min after administration of contrast agent of 0.1 mmol/kg gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA).