High-resolution renal MRA: Comparison of image quality and vessel depiction with different parallel imaging acceleration factors

2006 ◽  
Vol 24 (1) ◽  
pp. 95-100 ◽  
Author(s):  
Henrik J. Michaely ◽  
Karin A. Herrmann ◽  
Harald Kramer ◽  
Olaf Dietrich ◽  
Gerhard Laub ◽  
...  
2012 ◽  
Vol 2 ◽  
pp. 31 ◽  
Author(s):  
John N Morelli ◽  
Megan R Saettele ◽  
Rajesh A Rangaswamy ◽  
Lan Vu ◽  
Clint M Gerdes ◽  
...  

Interest in clinical brain magnetic resonance imaging using 32-channel head coils for signal reception continues to increase. The present investigation assesses possibilities for improving diffusion-weighted image quality using a 32-channel in comparison to a conventional 12-channel coil. The utility of single-shot (ss) and an approach to readout-segmented (rs) echo planar imaging (EPI) are examined using both head coils. Substantial image quality improvements are found with rs-EPI. Imaging with a 32-channel head coil allows for implementation of greater parallel imaging acceleration factors or acquisition of scans at a higher resolution. Specifically, higher resolution imaging with rs-EPI can be achieved by increasing the number of readout segments without increasing echo-spacing or echo time to the degree necessary with ss-EPI — a factor resulting in increased susceptibility artifact and reduced signal-to-noise with the latter.


Author(s):  
Shida Tan ◽  
Richard H. Livengood ◽  
Dane Scott ◽  
Roy Hallstein ◽  
Pat Pardy ◽  
...  

Abstract High resolution optical imaging is critical in assisting backside circuit edit (CE) and optical probing navigation. In this paper, we demonstrated improved optical image quality using VIS-NIR narrow band light emitting diode (LED) illumination in various FIB and optical probing platforms. The proof of concept was demonstrated with both common non-contact air gap lenses and solid immersion lenses (SIL).


Diagnostics ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 319
Author(s):  
Chan-Rok Park ◽  
Seong-Hyeon Kang ◽  
Young-Jin Lee

Recently, the total variation (TV) algorithm has been used for noise reduction distribution in degraded nuclear medicine images. To acquire positron emission tomography (PET) to correct the attenuation region in the PET/magnetic resonance (MR) system, the MR Dixon pulse sequence, which is based on controlled aliasing in parallel imaging, results from higher acceleration (CAIPI; MR-ACDixon-CAIPI) and generalized autocalibrating partially parallel acquisition (GRAPPA; MR-ACDixon-GRAPPA) algorithms are used. Therefore, this study aimed to evaluate the image performance of the TV noise reduction algorithm for PET/MR images using the Jaszczak phantom by injecting 18F radioisotopes with PET/MR, which is called mMR (Siemens, Germany), compared with conventional noise-reduction techniques such as Wiener and median filters. The contrast-to-noise (CNR) and coefficient of variation (COV) were used for quantitative analysis. Based on the results, PET images with the TV algorithm were improved by approximately 7.6% for CNR and decreased by approximately 20.0% for COV compared with conventional noise-reduction techniques. In particular, the image quality for the MR-ACDixon-CAIPI PET image was better than that of the MR-ACDixon-GRAPPA PET image. In conclusion, the TV noise-reduction algorithm is efficient for improving the PET image quality in PET/MR systems.


2007 ◽  
Vol 25 (4) ◽  
pp. 832-840 ◽  
Author(s):  
Katja A. Mende ◽  
Johannes M. Froehlich ◽  
Constantin von Weymarn ◽  
Romhild Hoogeveen ◽  
Thomas Kistler ◽  
...  

Author(s):  
Martin Georg Zeilinger ◽  
Marco Wiesmüller ◽  
Christoph Forman ◽  
Michaela Schmidt ◽  
Camila Munoz ◽  
...  

Abstract Objectives To evaluate an image-navigated isotropic high-resolution 3D late gadolinium enhancement (LGE) prototype sequence with compressed sensing and Dixon water-fat separation in a clinical routine setting. Material and methods Forty consecutive patients scheduled for cardiac MRI were enrolled prospectively and examined with 1.5 T MRI. Overall subjective image quality, LGE pattern and extent, diagnostic confidence for detection of LGE, and scan time were evaluated and compared to standard 2D LGE imaging. Robustness of Dixon fat suppression was evaluated for 3D Dixon LGE imaging. For statistical analysis, the non-parametric Wilcoxon rank sum test was performed. Results LGE was rated as ischemic in 9 patients and non-ischemic in 11 patients while it was absent in 20 patients. Image quality and diagnostic confidence were comparable between both techniques (p = 0.67 and p = 0.66, respectively). LGE extent with respect to segmental or transmural myocardial enhancement was identical between 2D and 3D (water-only and in-phase). LGE size was comparable (3D 8.4 ± 7.2 g, 2D 8.7 ± 7.3 g, p = 0.19). Good or excellent fat suppression was achieved in 93% of the 3D LGE datasets. In 6 patients with pericarditis, the 3D sequence with Dixon fat suppression allowed for a better detection of pericardial LGE. Scan duration was significantly longer for 3D imaging (2D median 9:32 min vs. 3D median 10:46 min, p = 0.001). Conclusion The 3D LGE sequence provides comparable LGE detection compared to 2D imaging and seems to be superior in evaluating the extent of pericardial involvement in patients suspected with pericarditis due to the robust Dixon fat suppression. Key Points • Three-dimensional LGE imaging provides high-resolution detection of myocardial scarring. • Robust Dixon water-fat separation aids in the assessment of pericardial disease. • The 2D image navigator technique enables 100% respiratory scan efficacy and permits predictable scan times.


2012 ◽  
Vol 33 (10) ◽  
pp. 1867-1874 ◽  
Author(s):  
J. Fruehwald-Pallamar ◽  
P. Szomolanyi ◽  
N. Fakhrai ◽  
A. Lunzer ◽  
M. Weber ◽  
...  

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