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Refocusing flip angle

WebDistribution of the isochromats for spin‐echo sequences using a constant refocusing flip angle of α = 90° (a,b) and for an optimized sequence using a first refocusing pulse with flip angle 90°+α/2 = 135° (c,d). The first (a,c) and the 20th (b,d) echo are shown. WebJul 1, 2024 · Recently, a variation of SSFSE with variable refocusing flip angles (variable refocusing single-shot FSE [vrfSSFSE]) has been described. 16 This flip angle modulation was originally introduced to reduce T2-decay–associated blurring, mostly in the context of volumetric imaging. 17 ⇓- 19 Coincidentally, the flip angle modulation also reduces …

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WebPurpose: To develop and validate clinically a single-shot fast spin echo (SSFSE) sequence utilizing variable flip angle refocusing pulses to shorten acquisition times via reductions in specific absorption rate (SAR) and improve image quality. Materials and methods: A variable refocusing flip angle SSFSE sequence (vrfSSFSE) was designed and implemented, with … WebMar 18, 2003 · Based on this interpretation, one may speculate that changing the refocusing flip angle to α 2 for such magnetization will lead to a new PSS, the trajectory of which will … liesl in the sound of music https://florentinta.com

Optimization of 3D-variable refocusing flip angle RARE ... - Springer

WebAug 26, 2016 · A single-shot fast spin-echo pulse sequence with variable refocusing flip angles and full-Fourier acquisition leads to a doubling of 3-T acquisition speed via reduced radiofrequency energy deposition and demonstrates significant improvements in perceived image quality and perceived diagnostic capability when evaluating structures in the pelvis. WebAug 1, 2024 · The pulse sequence required for a certain flip angle depending on the RF pulse type, coil load and imaging location. In fact, the RF pulse of MRI scan is characterized by several basic physical quantities of B1+ field, including (1) the RF pulse envelope B1+ ( t ), (2) the pulse width ( T ), and (3) the pulse bandwidth ( Δ f). WebApr 2, 2024 · Flip angle. The flip angle is usually at or close to 90 degrees for a spin-echo sequence but is less on gradient-echo sequences, commonly varying over a range of 10 to 80 degrees (usually denoted by α). For the basic GRE sequence FLASH, the larger flip angles give more T1 weighting to the image and the smaller flip angles give more T2, or ... mcm flash

Increased Speed and Image Quality for Pelvic Single-Shot Fast …

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Refocusing flip angle

Simultaneous Dual Contrast Weighting Using Double Echo …

National Center for Biotechnology Information WebSep 1, 2008 · A magnetization-prepared FLAIR-Cube with refocusing flip angle trains optimized for SNR and contrast can be used to characterize WM and cortical lesions at 7 …

Refocusing flip angle

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WebMay 28, 2016 · First, consider a small flip angle α (e.g., 5° to 30°). As can be seen in Figure 20-11, a small flip angle results in a large amount of (persistent) longitudinal magnetization after application of the RF Only gold members can continue reading. Log In or Register to continue You may also need Load more posts WebVariable refocusing flip angle single-shot fast spin echo imaging of liver lesions: increased speed and lesion contrast Compared to conventional SSFSE, vrfSSFSE resulted in improved lesion contrast on simultaneous PET/MRI in patients with liver metastases.

WebAbstract. Radiofrequency (RF) transmit field (B 1) mapping is a promising method in mitigating the B 1 inhomogeneity in various magnetic resonance imaging (MRI) applications. Although several phase- or magnitude-based B 1 mapping methods have been proposed, these methods often require complex modeling, long acquisition time, or specialized MRI … WebApr 26, 2004 · The raw signal may be corrected for refocusing flip angle modulation by inverting the expected signal modulation due to flip angle variation: (3) Because the correction amplifies noise as well as signal for the higher spatial frequencies, an overall increase in image noise is expected.

WebJul 8, 2024 · Properly designed variable refocusing flip angle echo trains can stabilize signal amplitude over the course of the echo train by initially storing magnetization in the longitudinal direction, with slow conversion back to … WebThe proposed single-breath-hold abdominal HASTE DL with variable refocusing FAs is feasible at 3 T within SAR limits and yields high image quality and diagnostic confidence …

WebMar 19, 2014 · The deviation is a function of the flip angle of the refocusing pulses, the sequence parameters ETL and ESP, as well as the time constants T 1 and T 2. The typical T 1 values in in vivo experiments are significantly higher than T 2 , and an approximate value of T 1 = 3 s can be assumed for accurate results, as shown in simulations.

liesl knoxWebApr 12, 2024 · The 3D TSE magnetic resonance sequence with a variable flip angle 16–21 is an emerging MRI technology. The 3D T1W BrainVIEW sequence, an advanced 3D TSE black-blood technology produced by Philips MRI, has been … liesl long canvas artWebMay 22, 2024 · A refocusing pulse of less than 180° can be considered an insufficient flipping of the transverse magnetization. The induced MR signal is diminished, because it … mcm food corp medley fl