The Experts below are selected from a list of 7329 Experts worldwide ranked by ideXlab platform
Fernando E. Boada - One of the best experts on this subject based on the ideXlab platform.
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High‐resolution spiral imaging on a whole‐body 7T scanner with minimized Image Blurring
Magnetic Resonance in Medicine, 2010Co-Authors: Yongxian Qian, Tamer S. Ibrahim, Tiejun Zhao, Fernando E. BoadaAbstract:High-resolution (∼0.22 mm) Images are preferably acquired on whole-body 7T scanners to visualize minianatomic structures in human brain. They usually need long acquisition time (∼12 min) in three-dimensional scans, even with both parallel imaging and partial Fourier samplings. The combined use of both fast imaging techniques, however, leads to occasionally visible undersampling artifacts. Spiral imaging has an advantage in acquisition efficiency over rectangular sampling, but its implementations are limited due to Image Blurring caused by a strong off-resonance effect at 7T. This study proposes a solution for minimizing Image Blurring while keeping spiral efficient. Image Blurring at 7T was, first, quantitatively investigated using computer simulations and point-spread functions. A combined use of multishot spirals and ultrashort echo time acquisitions was then employed to minimize off-resonance-induced Image Blurring. Experiments on phantoms and healthy subjects were performed on a whole-body 7T scanner to show the performance of the proposed method. The three-dimensional brain Images of human subjects were obtained at echo time = 1.18 ms, resolution = 0.22mm (field of view = 220mm, matrix size = 1024), and in-plane spiral shots = 128, using a home-developed ultrashort echo time sequence (acquisition-weighted stack of spirals). The total acquisition time for 60 partitions at pulse repetition time = 100 ms was 12.8 min without use of parallel imaging and partial Fourier sampling. The Blurring in these spiral Images was minimized to a level comparable to that in gradient-echo Images with rectangular acquisitions, while the spiral acquisition efficiency was maintained at eight. These Images showed that spiral imaging at 7T was feasible. Magn Reson Med, 2010. © 2010 Wiley-Liss, Inc.
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high resolution spiral imaging on a whole body 7t scanner with minimized Image Blurring
Magnetic Resonance in Medicine, 2010Co-Authors: Yongxian Qian, Tamer S. Ibrahim, Tiejun Zhao, Fernando E. BoadaAbstract:High-resolution (∼0.22 mm) Images are preferably acquired on whole-body 7T scanners to visualize minianatomic structures in human brain. They usually need long acquisition time (∼12 min) in three-dimensional scans, even with both parallel imaging and partial Fourier samplings. The combined use of both fast imaging techniques, however, leads to occasionally visible undersampling artifacts. Spiral imaging has an advantage in acquisition efficiency over rectangular sampling, but its implementations are limited due to Image Blurring caused by a strong off-resonance effect at 7T. This study proposes a solution for minimizing Image Blurring while keeping spiral efficient. Image Blurring at 7T was, first, quantitatively investigated using computer simulations and point-spread functions. A combined use of multishot spirals and ultrashort echo time acquisitions was then employed to minimize off-resonance-induced Image Blurring. Experiments on phantoms and healthy subjects were performed on a whole-body 7T scanner to show the performance of the proposed method. The three-dimensional brain Images of human subjects were obtained at echo time = 1.18 ms, resolution = 0.22mm (field of view = 220mm, matrix size = 1024), and in-plane spiral shots = 128, using a home-developed ultrashort echo time sequence (acquisition-weighted stack of spirals). The total acquisition time for 60 partitions at pulse repetition time = 100 ms was 12.8 min without use of parallel imaging and partial Fourier sampling. The Blurring in these spiral Images was minimized to a level comparable to that in gradient-echo Images with rectangular acquisitions, while the spiral acquisition efficiency was maintained at eight. These Images showed that spiral imaging at 7T was feasible. Magn Reson Med, 2010. © 2010 Wiley-Liss, Inc.
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High-resolution spiral imaging on a whole-body 7T scanner with minimized Image Blurring
Magnetic Resonance in Medicine, 2010Co-Authors: Yongxian Qian, Yik Kiong Hue, Tamer S. Ibrahim, Tiejun Zhao, Fernando E. BoadaAbstract:High-resolution (approximately 0.22 mm) Images are preferably acquired on whole-body 7T scanners to visualize minianatomic structures in human brain. They usually need long acquisition time ( approximately 12 min) in three-dimensional scans, even with both parallel imaging and partial Fourier samplings. The combined use of both fast imaging techniques, however, leads to occasionally visible undersampling artifacts. Spiral imaging has an advantage in acquisition efficiency over rectangular sampling, but its implementations are limited due to Image Blurring caused by a strong off-resonance effect at 7T. This study proposes a solution for minimizing Image Blurring while keeping spiral efficient. Image Blurring at 7T was, first, quantitatively investigated using computer simulations and point-spread functions. A combined use of multishot spirals and ultrashort echo time acquisitions was then employed to minimize off-resonance-induced Image Blurring. Experiments on phantoms and healthy subjects were performed on a whole-body 7T scanner to show the performance of the proposed method. The three-dimensional brain Images of human subjects were obtained at echo time = 1.18 ms, resolution = 0.22 mm (field of view = 220 mm, matrix size = 1024), and in-plane spiral shots = 128, using a home-developed ultrashort echo time sequence (acquisition-weighted stack of spirals). The total acquisition time for 60 partitions at pulse repetition time = 100 ms was 12.8 min without use of parallel imaging and partial Fourier sampling. The Blurring in these spiral Images was minimized to a level comparable to that in gradient-echo Images with rectangular acquisitions, while the spiral acquisition efficiency was maintained at eight. These Images showed that spiral imaging at 7T was feasible.
Yongxian Qian - One of the best experts on this subject based on the ideXlab platform.
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High‐resolution spiral imaging on a whole‐body 7T scanner with minimized Image Blurring
Magnetic Resonance in Medicine, 2010Co-Authors: Yongxian Qian, Tamer S. Ibrahim, Tiejun Zhao, Fernando E. BoadaAbstract:High-resolution (∼0.22 mm) Images are preferably acquired on whole-body 7T scanners to visualize minianatomic structures in human brain. They usually need long acquisition time (∼12 min) in three-dimensional scans, even with both parallel imaging and partial Fourier samplings. The combined use of both fast imaging techniques, however, leads to occasionally visible undersampling artifacts. Spiral imaging has an advantage in acquisition efficiency over rectangular sampling, but its implementations are limited due to Image Blurring caused by a strong off-resonance effect at 7T. This study proposes a solution for minimizing Image Blurring while keeping spiral efficient. Image Blurring at 7T was, first, quantitatively investigated using computer simulations and point-spread functions. A combined use of multishot spirals and ultrashort echo time acquisitions was then employed to minimize off-resonance-induced Image Blurring. Experiments on phantoms and healthy subjects were performed on a whole-body 7T scanner to show the performance of the proposed method. The three-dimensional brain Images of human subjects were obtained at echo time = 1.18 ms, resolution = 0.22mm (field of view = 220mm, matrix size = 1024), and in-plane spiral shots = 128, using a home-developed ultrashort echo time sequence (acquisition-weighted stack of spirals). The total acquisition time for 60 partitions at pulse repetition time = 100 ms was 12.8 min without use of parallel imaging and partial Fourier sampling. The Blurring in these spiral Images was minimized to a level comparable to that in gradient-echo Images with rectangular acquisitions, while the spiral acquisition efficiency was maintained at eight. These Images showed that spiral imaging at 7T was feasible. Magn Reson Med, 2010. © 2010 Wiley-Liss, Inc.
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high resolution spiral imaging on a whole body 7t scanner with minimized Image Blurring
Magnetic Resonance in Medicine, 2010Co-Authors: Yongxian Qian, Tamer S. Ibrahim, Tiejun Zhao, Fernando E. BoadaAbstract:High-resolution (∼0.22 mm) Images are preferably acquired on whole-body 7T scanners to visualize minianatomic structures in human brain. They usually need long acquisition time (∼12 min) in three-dimensional scans, even with both parallel imaging and partial Fourier samplings. The combined use of both fast imaging techniques, however, leads to occasionally visible undersampling artifacts. Spiral imaging has an advantage in acquisition efficiency over rectangular sampling, but its implementations are limited due to Image Blurring caused by a strong off-resonance effect at 7T. This study proposes a solution for minimizing Image Blurring while keeping spiral efficient. Image Blurring at 7T was, first, quantitatively investigated using computer simulations and point-spread functions. A combined use of multishot spirals and ultrashort echo time acquisitions was then employed to minimize off-resonance-induced Image Blurring. Experiments on phantoms and healthy subjects were performed on a whole-body 7T scanner to show the performance of the proposed method. The three-dimensional brain Images of human subjects were obtained at echo time = 1.18 ms, resolution = 0.22mm (field of view = 220mm, matrix size = 1024), and in-plane spiral shots = 128, using a home-developed ultrashort echo time sequence (acquisition-weighted stack of spirals). The total acquisition time for 60 partitions at pulse repetition time = 100 ms was 12.8 min without use of parallel imaging and partial Fourier sampling. The Blurring in these spiral Images was minimized to a level comparable to that in gradient-echo Images with rectangular acquisitions, while the spiral acquisition efficiency was maintained at eight. These Images showed that spiral imaging at 7T was feasible. Magn Reson Med, 2010. © 2010 Wiley-Liss, Inc.
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High-resolution spiral imaging on a whole-body 7T scanner with minimized Image Blurring
Magnetic Resonance in Medicine, 2010Co-Authors: Yongxian Qian, Yik Kiong Hue, Tamer S. Ibrahim, Tiejun Zhao, Fernando E. BoadaAbstract:High-resolution (approximately 0.22 mm) Images are preferably acquired on whole-body 7T scanners to visualize minianatomic structures in human brain. They usually need long acquisition time ( approximately 12 min) in three-dimensional scans, even with both parallel imaging and partial Fourier samplings. The combined use of both fast imaging techniques, however, leads to occasionally visible undersampling artifacts. Spiral imaging has an advantage in acquisition efficiency over rectangular sampling, but its implementations are limited due to Image Blurring caused by a strong off-resonance effect at 7T. This study proposes a solution for minimizing Image Blurring while keeping spiral efficient. Image Blurring at 7T was, first, quantitatively investigated using computer simulations and point-spread functions. A combined use of multishot spirals and ultrashort echo time acquisitions was then employed to minimize off-resonance-induced Image Blurring. Experiments on phantoms and healthy subjects were performed on a whole-body 7T scanner to show the performance of the proposed method. The three-dimensional brain Images of human subjects were obtained at echo time = 1.18 ms, resolution = 0.22 mm (field of view = 220 mm, matrix size = 1024), and in-plane spiral shots = 128, using a home-developed ultrashort echo time sequence (acquisition-weighted stack of spirals). The total acquisition time for 60 partitions at pulse repetition time = 100 ms was 12.8 min without use of parallel imaging and partial Fourier sampling. The Blurring in these spiral Images was minimized to a level comparable to that in gradient-echo Images with rectangular acquisitions, while the spiral acquisition efficiency was maintained at eight. These Images showed that spiral imaging at 7T was feasible.
Ryuji Nishi - One of the best experts on this subject based on the ideXlab platform.
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the influence of structure depth on Image Blurring of micrometres thick specimens in mev transmission electron imaging
Micron, 2016Co-Authors: Fang Wang, Ryuji NishiAbstract:Abstract This study investigates the influence of structure depth on Image Blurring of micrometres-thick films by experiment and simulation with a conventional transmission electron microscope (TEM). First, ultra-high-voltage electron microscope (ultra-HVEM) Images of nanometer gold particles embedded in thick epoxy-resin films were acquired in the experiment and compared with simulated Images. Then, variations of Image Blurring of gold particles at different depths were evaluated by calculating the particle diameter. The results showed that with a decrease in depth, Image Blurring increased. This depth-related property was more apparent for thicker specimens. Fortunately, larger particle depth involves less Image Blurring, even for a 10-μm-thick epoxy-resin film. The quality dependence on depth of a 3D reconstruction of particle structures in thick specimens was revealed by electron tomography. The evolution of Image Blurring with structure depth is determined mainly by multiple elastic scattering effects. Thick specimens of heavier materials produced more Blurring due to a larger lateral spread of electrons after scattering from the structure. Nevertheless, increasing electron energy to 2 MeV can reduce Blurring and produce an acceptable Image quality for thick specimens in the TEM.
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Image Blurring of thick specimens due to mev transmission electron scattering a monte carlo study
Journal of Electron Microscopy, 2011Co-Authors: Fang Wang, Haibo Zhang, Ryuji Nishi, Akio TakaokaAbstract:: Image Blurring of MeV transmission electrons for gold nanoparticles on the top surface of micrometer-thick specimens has been investigated using the Monte Carlo simulation. Both the simulated line density profile and therefore Image Blurring were in good agreement with the experimental ones in the ultrahigh voltage electron microscope. Quantitative effects of specimen thickness and electron energy on Image Blurring were presented, in which the specimen thickness had a greater influence. Image Blurring was demonstrated to be caused mainly by multiple elastic scattering, but it could be reduced to several nanometers for a 5 µm thick epoxy-resin specimen at the electron energy of 2 MeV.
Tamer S. Ibrahim - One of the best experts on this subject based on the ideXlab platform.
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High‐resolution spiral imaging on a whole‐body 7T scanner with minimized Image Blurring
Magnetic Resonance in Medicine, 2010Co-Authors: Yongxian Qian, Tamer S. Ibrahim, Tiejun Zhao, Fernando E. BoadaAbstract:High-resolution (∼0.22 mm) Images are preferably acquired on whole-body 7T scanners to visualize minianatomic structures in human brain. They usually need long acquisition time (∼12 min) in three-dimensional scans, even with both parallel imaging and partial Fourier samplings. The combined use of both fast imaging techniques, however, leads to occasionally visible undersampling artifacts. Spiral imaging has an advantage in acquisition efficiency over rectangular sampling, but its implementations are limited due to Image Blurring caused by a strong off-resonance effect at 7T. This study proposes a solution for minimizing Image Blurring while keeping spiral efficient. Image Blurring at 7T was, first, quantitatively investigated using computer simulations and point-spread functions. A combined use of multishot spirals and ultrashort echo time acquisitions was then employed to minimize off-resonance-induced Image Blurring. Experiments on phantoms and healthy subjects were performed on a whole-body 7T scanner to show the performance of the proposed method. The three-dimensional brain Images of human subjects were obtained at echo time = 1.18 ms, resolution = 0.22mm (field of view = 220mm, matrix size = 1024), and in-plane spiral shots = 128, using a home-developed ultrashort echo time sequence (acquisition-weighted stack of spirals). The total acquisition time for 60 partitions at pulse repetition time = 100 ms was 12.8 min without use of parallel imaging and partial Fourier sampling. The Blurring in these spiral Images was minimized to a level comparable to that in gradient-echo Images with rectangular acquisitions, while the spiral acquisition efficiency was maintained at eight. These Images showed that spiral imaging at 7T was feasible. Magn Reson Med, 2010. © 2010 Wiley-Liss, Inc.
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high resolution spiral imaging on a whole body 7t scanner with minimized Image Blurring
Magnetic Resonance in Medicine, 2010Co-Authors: Yongxian Qian, Tamer S. Ibrahim, Tiejun Zhao, Fernando E. BoadaAbstract:High-resolution (∼0.22 mm) Images are preferably acquired on whole-body 7T scanners to visualize minianatomic structures in human brain. They usually need long acquisition time (∼12 min) in three-dimensional scans, even with both parallel imaging and partial Fourier samplings. The combined use of both fast imaging techniques, however, leads to occasionally visible undersampling artifacts. Spiral imaging has an advantage in acquisition efficiency over rectangular sampling, but its implementations are limited due to Image Blurring caused by a strong off-resonance effect at 7T. This study proposes a solution for minimizing Image Blurring while keeping spiral efficient. Image Blurring at 7T was, first, quantitatively investigated using computer simulations and point-spread functions. A combined use of multishot spirals and ultrashort echo time acquisitions was then employed to minimize off-resonance-induced Image Blurring. Experiments on phantoms and healthy subjects were performed on a whole-body 7T scanner to show the performance of the proposed method. The three-dimensional brain Images of human subjects were obtained at echo time = 1.18 ms, resolution = 0.22mm (field of view = 220mm, matrix size = 1024), and in-plane spiral shots = 128, using a home-developed ultrashort echo time sequence (acquisition-weighted stack of spirals). The total acquisition time for 60 partitions at pulse repetition time = 100 ms was 12.8 min without use of parallel imaging and partial Fourier sampling. The Blurring in these spiral Images was minimized to a level comparable to that in gradient-echo Images with rectangular acquisitions, while the spiral acquisition efficiency was maintained at eight. These Images showed that spiral imaging at 7T was feasible. Magn Reson Med, 2010. © 2010 Wiley-Liss, Inc.
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High-resolution spiral imaging on a whole-body 7T scanner with minimized Image Blurring
Magnetic Resonance in Medicine, 2010Co-Authors: Yongxian Qian, Yik Kiong Hue, Tamer S. Ibrahim, Tiejun Zhao, Fernando E. BoadaAbstract:High-resolution (approximately 0.22 mm) Images are preferably acquired on whole-body 7T scanners to visualize minianatomic structures in human brain. They usually need long acquisition time ( approximately 12 min) in three-dimensional scans, even with both parallel imaging and partial Fourier samplings. The combined use of both fast imaging techniques, however, leads to occasionally visible undersampling artifacts. Spiral imaging has an advantage in acquisition efficiency over rectangular sampling, but its implementations are limited due to Image Blurring caused by a strong off-resonance effect at 7T. This study proposes a solution for minimizing Image Blurring while keeping spiral efficient. Image Blurring at 7T was, first, quantitatively investigated using computer simulations and point-spread functions. A combined use of multishot spirals and ultrashort echo time acquisitions was then employed to minimize off-resonance-induced Image Blurring. Experiments on phantoms and healthy subjects were performed on a whole-body 7T scanner to show the performance of the proposed method. The three-dimensional brain Images of human subjects were obtained at echo time = 1.18 ms, resolution = 0.22 mm (field of view = 220 mm, matrix size = 1024), and in-plane spiral shots = 128, using a home-developed ultrashort echo time sequence (acquisition-weighted stack of spirals). The total acquisition time for 60 partitions at pulse repetition time = 100 ms was 12.8 min without use of parallel imaging and partial Fourier sampling. The Blurring in these spiral Images was minimized to a level comparable to that in gradient-echo Images with rectangular acquisitions, while the spiral acquisition efficiency was maintained at eight. These Images showed that spiral imaging at 7T was feasible.
Tiejun Zhao - One of the best experts on this subject based on the ideXlab platform.
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High‐resolution spiral imaging on a whole‐body 7T scanner with minimized Image Blurring
Magnetic Resonance in Medicine, 2010Co-Authors: Yongxian Qian, Tamer S. Ibrahim, Tiejun Zhao, Fernando E. BoadaAbstract:High-resolution (∼0.22 mm) Images are preferably acquired on whole-body 7T scanners to visualize minianatomic structures in human brain. They usually need long acquisition time (∼12 min) in three-dimensional scans, even with both parallel imaging and partial Fourier samplings. The combined use of both fast imaging techniques, however, leads to occasionally visible undersampling artifacts. Spiral imaging has an advantage in acquisition efficiency over rectangular sampling, but its implementations are limited due to Image Blurring caused by a strong off-resonance effect at 7T. This study proposes a solution for minimizing Image Blurring while keeping spiral efficient. Image Blurring at 7T was, first, quantitatively investigated using computer simulations and point-spread functions. A combined use of multishot spirals and ultrashort echo time acquisitions was then employed to minimize off-resonance-induced Image Blurring. Experiments on phantoms and healthy subjects were performed on a whole-body 7T scanner to show the performance of the proposed method. The three-dimensional brain Images of human subjects were obtained at echo time = 1.18 ms, resolution = 0.22mm (field of view = 220mm, matrix size = 1024), and in-plane spiral shots = 128, using a home-developed ultrashort echo time sequence (acquisition-weighted stack of spirals). The total acquisition time for 60 partitions at pulse repetition time = 100 ms was 12.8 min without use of parallel imaging and partial Fourier sampling. The Blurring in these spiral Images was minimized to a level comparable to that in gradient-echo Images with rectangular acquisitions, while the spiral acquisition efficiency was maintained at eight. These Images showed that spiral imaging at 7T was feasible. Magn Reson Med, 2010. © 2010 Wiley-Liss, Inc.
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high resolution spiral imaging on a whole body 7t scanner with minimized Image Blurring
Magnetic Resonance in Medicine, 2010Co-Authors: Yongxian Qian, Tamer S. Ibrahim, Tiejun Zhao, Fernando E. BoadaAbstract:High-resolution (∼0.22 mm) Images are preferably acquired on whole-body 7T scanners to visualize minianatomic structures in human brain. They usually need long acquisition time (∼12 min) in three-dimensional scans, even with both parallel imaging and partial Fourier samplings. The combined use of both fast imaging techniques, however, leads to occasionally visible undersampling artifacts. Spiral imaging has an advantage in acquisition efficiency over rectangular sampling, but its implementations are limited due to Image Blurring caused by a strong off-resonance effect at 7T. This study proposes a solution for minimizing Image Blurring while keeping spiral efficient. Image Blurring at 7T was, first, quantitatively investigated using computer simulations and point-spread functions. A combined use of multishot spirals and ultrashort echo time acquisitions was then employed to minimize off-resonance-induced Image Blurring. Experiments on phantoms and healthy subjects were performed on a whole-body 7T scanner to show the performance of the proposed method. The three-dimensional brain Images of human subjects were obtained at echo time = 1.18 ms, resolution = 0.22mm (field of view = 220mm, matrix size = 1024), and in-plane spiral shots = 128, using a home-developed ultrashort echo time sequence (acquisition-weighted stack of spirals). The total acquisition time for 60 partitions at pulse repetition time = 100 ms was 12.8 min without use of parallel imaging and partial Fourier sampling. The Blurring in these spiral Images was minimized to a level comparable to that in gradient-echo Images with rectangular acquisitions, while the spiral acquisition efficiency was maintained at eight. These Images showed that spiral imaging at 7T was feasible. Magn Reson Med, 2010. © 2010 Wiley-Liss, Inc.
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High-resolution spiral imaging on a whole-body 7T scanner with minimized Image Blurring
Magnetic Resonance in Medicine, 2010Co-Authors: Yongxian Qian, Yik Kiong Hue, Tamer S. Ibrahim, Tiejun Zhao, Fernando E. BoadaAbstract:High-resolution (approximately 0.22 mm) Images are preferably acquired on whole-body 7T scanners to visualize minianatomic structures in human brain. They usually need long acquisition time ( approximately 12 min) in three-dimensional scans, even with both parallel imaging and partial Fourier samplings. The combined use of both fast imaging techniques, however, leads to occasionally visible undersampling artifacts. Spiral imaging has an advantage in acquisition efficiency over rectangular sampling, but its implementations are limited due to Image Blurring caused by a strong off-resonance effect at 7T. This study proposes a solution for minimizing Image Blurring while keeping spiral efficient. Image Blurring at 7T was, first, quantitatively investigated using computer simulations and point-spread functions. A combined use of multishot spirals and ultrashort echo time acquisitions was then employed to minimize off-resonance-induced Image Blurring. Experiments on phantoms and healthy subjects were performed on a whole-body 7T scanner to show the performance of the proposed method. The three-dimensional brain Images of human subjects were obtained at echo time = 1.18 ms, resolution = 0.22 mm (field of view = 220 mm, matrix size = 1024), and in-plane spiral shots = 128, using a home-developed ultrashort echo time sequence (acquisition-weighted stack of spirals). The total acquisition time for 60 partitions at pulse repetition time = 100 ms was 12.8 min without use of parallel imaging and partial Fourier sampling. The Blurring in these spiral Images was minimized to a level comparable to that in gradient-echo Images with rectangular acquisitions, while the spiral acquisition efficiency was maintained at eight. These Images showed that spiral imaging at 7T was feasible.
