A locally segmented reconstruction method for parallel imaging

2020 ◽  
Vol 84 (3) ◽  
pp. 1638-1647
Author(s):  
Seohee So ◽  
Hyunseok Seo ◽  
HyunWook Park
Keyword(s):  
Parallel Imaging ◽  
Reconstruction Method

scholarly journals Experimental testing on phantom image for improved MRI compressed sensing

2020 ◽  
Vol 12 (1) ◽  
pp. 18-21
Author(s):  
Aleksandar Kamilovski
Keyword(s):  
Compressed Sensing ◽  
Wavelet Transforms ◽  
Parallel Imaging ◽  
Experimental Testing ◽  
Imaging Techniques ◽  
Brain Mri ◽  
Experimental Tests ◽  
Reconstruction Method ◽  
Test Image ◽  
Phantom Image

This paper presents a possible way for improving the techniques of compressed sensing and parallel imaging techniques for brain MRI. Experimental tests have been performed over a phantom test image. An exclusive elliptical sampling mask has been generated, which in combination with double-density wavelet transforms offers improvement over the standard approach. Additional tests undertaken as part of this research propose the usage of nonlinear reconstruction method, generated elliptical sampling mask and double-density wavelet transform for application of compressed sensing to brain MRI. An assessment of the results for diagnostic usage has been done by a specialist of radiology.

scholarly journals A fast Edge-preserving Bayesian reconstruction method for Parallel Imaging applications in cardiac MRI

2010 ◽  
Vol 65 (1) ◽  
pp. 184-189 ◽  
Author(s):  
Gurmeet Singh ◽  
Ashish Raj ◽  
Bryan Kressler ◽  
Thanh D. Nguyen ◽  
Pascal Spincemaille ◽  
...  
Keyword(s):  
Cardiac Mri ◽  
Parallel Imaging ◽  
Reconstruction Method ◽  
Edge Preserving ◽  
Bayesian Reconstruction

scholarly journals Diffusion Acceleration with Gaussian process Estimated Reconstruction (DAGER)

2018 ◽  
Author(s):  
Wenchuan Wu ◽  
Peter J Koopmans ◽  
Jesper Andersson ◽  
Karla L Miller
Keyword(s):  
Diffusion Mri ◽  
Parallel Imaging ◽  
Angular Resolution ◽  
Pulse Sequences ◽  
Superior Performance ◽  
Reconstruction Method ◽  
Scan Time ◽  
Standard Pulse ◽  
A Minor

AbstractPurposeImage acceleration provides multiple benefits to diffusion MRI (dMRI), with in-plane acceleration reducing distortion and slice-wise acceleration increasing the number of directions that can be acquired in a given scan time. However, as acceleration factors increase, the reconstruction problem becomes ill-conditioned, particularly when using both in-plane acceleration and simultaneous multi-slice (SMS) imaging. In this work, we develop a novel reconstruction method for in-vivo MRI acquisition that provides acceleration beyond what conventional techniques can achieve.Theory and MethodsWe propose to constrain the reconstruction in the spatial (k) domain by incorporating information from the angular (q) domain. This approach exploits smoothness of the signal in q-space using Gaussian processes, as has previously been exploited in post-reconstruction analysis. We demonstrate in-plane acceleration exceeding the theoretical parallel imaging limits, and SMS combined with in-plane acceleration at a total factor of 12. This reconstruction is cast within a Bayesian framework that incorporates estimation of smoothness hyper-parameters, with no need for manual tuning.ResultsSimulations and in vivo results demonstrate superior performance of the proposed method compared with conventional parallel imaging methods. These improvements are achieved without loss of spatial or angular resolution and require only a minor modification to standard pulse sequences.ConclusionThe proposed method provides improvements over existing methods for diffusion acceleration, particularly for high SMS acceleration with in-plane undersampling.

Three-dimensional reconstruction of the 40S ribosomal subunit from rabbit reticulocytes

1987 ◽  
Vol 45 ◽  
pp. 936-937
Author(s):  
Neng-Yu Zhang ◽  
Terence Wagenknecht ◽  
Michael Radermacher ◽  
Tom Obrig ◽  
Joachim Frank
Keyword(s):  
Three Dimensional ◽  
Ribosomal Subunit ◽  
Uranyl Acetate ◽  
Reconstruction Method ◽  
Single Exposure ◽  
Electron Dose ◽  
Ribosomal Subunits ◽  
40S Ribosomal Subunit ◽  
Dimensional Reconstruction ◽  
Rabbit Reticulocytes

We have reconstructed the 40S ribosomal subunit at a resolution of 4 nm using the single-exposure pseudo-conical reconstruction method of Radermacher et al.Small (40S) ribosomal subunits were Isolated from rabbit reticulocytes, applied to grids and negatively stained (0.5% uranyl acetate) in a manner that “sandwiches” the specimen between two layers of carbon. Regions of the grid exhibiting uniform and thick staining were identified and photographed twice (magnification 49,000X). The first micrograph was always taken with the specimen tilted by 50° and the second was of the Identical area untilted (Fig. 1). For each of the micrographs the specimen was subjected to an electron dose of 2000-3000 el/nm2.Three hundred thirty particles appearing in the L view (defined in [4]) were selected from both tilted- and untilted-specimen micrographs. The untilted particles were aligned and their rotational alignment produced the azimuthal angles of the tilted particles in the conical tilt series.

Design of a Spectroscopic Low-Energy Emission Microscope

1990 ◽  
Vol 48 (1) ◽  
pp. 358-359
Author(s):  
Lee H. Veneklasen
Keyword(s):  
Parallel Imaging ◽  
Objective Lens ◽  
Energy Window ◽  
Flat Surfaces ◽  
Beam Voltage ◽  
New Instrument ◽  
Real Time Image ◽  
Image Planes ◽  
Backscatter Diffraction ◽  
Time Image

This paper discusses some of the unique aspects of a spectroscopic emission microscope now being tested in Clausthal. The instrument is designed for the direct parallel imaging of both elastic and inelastic electrons from flat surfaces. Elastic contrast modes of the familiar LEEM include large and small angle LEED, mirror microscopy, backscatter diffraction contrast (for imaging of surface structure), and phase contrast (for imaging of step dynamics)(1). Inelastic modes include topology sensitive secondary, and work function sensitive photoemission. Most important, the new instrument will also allow analytical imaging using characteristic Auger or soft X-ray emissions. The basic instrument has been described by Bauer and Telieps (2). This configuration has been redesigned to include an airlock, and a LaB6 gun, triple condensor lens, magnetic objective lens, a double focussing separator field, an imaging energy analyzer, and a real time image processor.Fig. 1 shows the new configuration. The basic beam voltage supply Vo = 20 KV, upon which separate supplies for the gun Vg, specimen Vs, lens electrode Vf, and analyzer bias Vb float. The incident energy at the sample can be varied from Vs = 0-1 KV for elastic imaging, or from Vg + Vs = (3 + Vs) KV for inelastic imaging. The image energy window Vs±V/2 may be varied without readjusting either the illumation, or imaging/analyzer optics. The diagram shows conjugate diffraction and image planes. The apertures defining incoming Humiliation and outgoing image angles are placed below the separator magnet to allow for their independent optimization. The instrument can illuminate and image 0.5-100 μm fields at 0-1 keV emission energies with an energy window down to 0.2 eV.

Coarctation of the abdominal aorta: Demonstration of a rare anomaly using contrast-enhanced MR-angiography

VASA ◽  
2009 ◽  
Vol 38 (1) ◽  
pp. 66-71 ◽  
Author(s):  
Schubert
Keyword(s):  
Abdominal Aorta ◽  
Mr Angiography ◽  
Parallel Imaging ◽  
Left Renal Vein ◽  
Systemic Hypertension ◽  
Contrast Enhanced ◽  
Younger Age ◽  
Maximum Intensity Projections ◽  
Collateral Vessels ◽  
First Time

We describe a case of aortic coarctation at the level of the infrarenal abdominal aorta which is encountered in less than six individuals in one million. In contrast to aortic narrowing above or including the renal arteries, this seems to be a relatively benign anomaly without systemic hypertension or impaired renal function. For the first time in this type of anomaly, contrast-enhanced MR angiography (ce-MRA) on a multi-receiver channel MR system, with an 8-channel phased array coil and parallel imaging was used. Ce-MRA displayed a tortuous, narrowed aortic segment that was found to be associated with mesenteric artery stenosis and compression of the orthotopic left renal vein, also known as the nutcracker phenomenon. All major aortic branches could be depicted using 3D surface-shaded displays and subvolume maximum intensity projections (MIPs). Collateral vessels of the abdominal wall were identified using whole-volume MIPs. Since the majority of aortic malformations are diagnosed at a younger age, and many suffer from renal insufficiency, we conclude that ce-MRA will eventually place conventional DSA as the modality of choice in malformations of the abdominal aorta.

Development of Waveform Reconstruction Method with Current Transformer Saturation

2009 ◽  
Vol 129 (1) ◽  
pp. 15-21 ◽  
Author(s):  
Shoichi Urano ◽  
Takeshi Yamada ◽  
Yoshifumi Ooura ◽  
Youheng Xu ◽  
Yasutaka Yamaguchi ◽  
...  
Keyword(s):  
Current Transformer ◽  
Reconstruction Method
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