scholarly journals Variable velocity encoding in a three-dimensional, three-directional phase contrast sequence: Evaluation in phantom and volunteers

2012 ◽  
Vol 36 (6) ◽  
pp. 1450-1459 ◽  
Author(s):  
Anders Nilsson ◽  
Karin Markenroth Bloch ◽  
Marcus Carlsson ◽  
Einar Heiberg ◽  
Freddy Ståhlberg
Keyword(s):  
Phase Contrast ◽  
Three Dimensional ◽  
Variable Velocity ◽  
Phase Contrast Sequence

A linearity test for thick specimens imaged by HVEM over a 180° angular range

1991 ◽  
Vol 49 ◽  
pp. 552-553
Author(s):  
Yu Liu
Keyword(s):  
Phase Contrast ◽  
Three Dimensional ◽  
Angular Range ◽  
Two Dimensional ◽  
Back Projection ◽  
Line Integral ◽  
Exponential Law ◽  
Transmission Electron ◽  
Absorption Law ◽  
Linearity Test

The image obtained in a transmission electron microscope is the two-dimensional projection of a three-dimensional (3D) object. The 3D reconstruction of the object can be calculated from a series of projections by back-projection, but this algorithm assumes that the image is linearly related to a line integral of the object function. However, there are two kinds of contrast in electron microscopy, scattering and phase contrast, of which only the latter is linear with the optical density (OD) in the micrograph. Therefore the OD can be used as a measure of the projection only for thin specimens where phase contrast dominates the image. For thick specimens, where scattering contrast predominates, an exponential absorption law holds, and a logarithm of OD must be used. However, for large thicknesses, the simple exponential law might break down due to multiple and inelastic scattering.

scholarly journals Vascular Supply of the Human Spiral Ganglion: Novel Three-Dimensional Analysis Using Synchrotron Phase-Contrast Imaging and Histology

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Xueshuang Mei ◽  
Rudolf Glueckert ◽  
Annelies Schrott-Fischer ◽  
Hao Li ◽  
Hanif M. Ladak ◽  
...  
Keyword(s):  
Blood Supply ◽  
Phase Contrast ◽  
Spiral Ganglion ◽  
Three Dimensional ◽  
Vascular Anatomy ◽  
Helical Structure ◽  
Vascular Supply ◽  
Phase Contrast Imaging ◽  
Contrast Imaging ◽  
Temporal Bones

AbstractHuman spiral ganglion (HSG) cell bodies located in the bony cochlea depend on a rich vascular supply to maintain excitability. These neurons are targeted by cochlear implantation (CI) to treat deafness, and their viability is critical to ensure successful clinical outcomes. The blood supply of the HSG is difficult to study due to its helical structure and encasement in hard bone. The objective of this study was to present the first three-dimensional (3D) reconstruction and analysis of the HSG blood supply using synchrotron radiation phase-contrast imaging (SR-PCI) in combination with histological analyses of archival human cochlear sections. Twenty-six human temporal bones underwent SR-PCI. Data were processed using volume-rendering software, and a representative three-dimensional (3D) model was created to allow visualization of the vascular anatomy. Histologic analysis was used to verify the segmentations. Results revealed that the HSG is supplied by radial vascular twigs which are separate from the rest of the inner ear and encased in bone. Unlike with most organs, the arteries and veins in the human cochlea do not follow the same conduits. There is a dual venous outflow and a modiolar arterial supply. This organization may explain why the HSG may endure even in cases of advanced cochlear pathology.

Magnetic resonance velocity imaging using a fast spiral phase contrast sequence

1994 ◽  
Vol 32 (4) ◽  
pp. 476-483 ◽  
Author(s):  
G. Bruce Pike ◽  
Craig H. Meyer ◽  
Thomas J. Brosnan ◽  
Norbert J. Pelc
Keyword(s):  
Magnetic Resonance ◽  
Phase Contrast ◽  
Velocity Imaging ◽  
Spiral Phase ◽  
Phase Contrast Sequence

scholarly journals Three-dimensional phase contrast angiography of the mouse aortic arch using spiral MRI

2011 ◽  
Vol 66 (5) ◽  
pp. 1382-1390 ◽  
Author(s):  
Robert L. Janiczek ◽  
Brett R. Blackman ◽  
R. Jack Roy ◽  
Craig H. Meyer ◽  
Scott T. Acton ◽  
...  
Keyword(s):  
Aortic Arch ◽  
Phase Contrast ◽  
Three Dimensional ◽  
Contrast Angiography ◽  
Spiral Mri

In Vivo Tracking of the Human Patella Using Cine Phase Contrast Magnetic Resonance Imaging

1999 ◽  
Vol 121 (6) ◽  
pp. 650-656 ◽  
Author(s):  
F. T. Sheehan ◽  
F. E. Zajac ◽  
J. E. Drace
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Knee Joint ◽  
Phase Contrast ◽  
Three Dimensional ◽  
Resonance Imaging ◽  
Contrast Magnetic Resonance ◽  
Knee Joint Kinematics ◽  
Cine Phase Contrast

Improper patellar tracking is often considered to be the cause of patellar-femoral pain. Unfortunately, our knowledge of patellar-femoral-tibial (knee) joint kinematics is severely limited due to a lack of three-dimensional, noninvasive, in vivo measurement techniques. This study presents the first large-scale, dynamic, three-dimensional, noninvasive, in vivo study of nonimpaired knee joint kinematics during volitional leg extensions. Cine-phase contrast magnetic resonance imaging was used to measure the velocity profiles of the patella, femur, and tibia in 18 unimpaired knees during leg extensions, resisted by a 34 N weight. Bone displacements were calculated through integration and then converted into three-dimensional orientation angles. We found that the patella displaced laterally, superiorly, and anteriorly as the knee extended. Further, patellar flexion lagged knee flexion, patellar tilt was variable, and patellar rotation was fairly constant throughout extension.

Insight into Bile Duct Reaction to Obstruction from a Three-dimensional Perspective Using ex Vivo Phase-Contrast CT

Radiology ◽  
2021 ◽  
pp. 203967
Author(s):  
Wen-Juan Lv ◽  
Xin-Yan Zhao ◽  
Dou-Dou Hu ◽  
Xiao-Hong Xin ◽  
Li-Li Qin ◽  
...  
Keyword(s):  
Bile Duct ◽  
Phase Contrast ◽  
Ex Vivo ◽  
Three Dimensional ◽  
Contrast Ct ◽  
Insight Into

Magnetresonanzphasenkontrastgeschwindigkeitsmessungen als noninvasive Nachbeobachtungsmaßnahme nach perkutaner transluminaler Angioplastie

VASA ◽  
2002 ◽  
Vol 31 (4) ◽  
pp. 235-240 ◽  
Author(s):  
Heverhagen ◽  
Wagner ◽  
Bandorski ◽  
Hoppe ◽  
Alfke
Keyword(s):  
Phase Contrast ◽  
Ankle Brachial Index ◽  
Transluminal Angioplasty ◽  
Walking Distance ◽  
Slice Thickness ◽  
Non Invasive ◽  
The Mean ◽  
Percutaneous Transluminal ◽  
Phase Contrast Sequence

Background: The aim of this study was to evaluate magnetic resonance phase contrast velocimetry (MRVL) as a non-invasive follow up tool to assess restenosis after percutaneous transluminal angioplasty (PTA). Patients and methods: We prospectively investigated 51 consecutive patients who underwent PTA of the femoropopliteal region. MRVL was conducted prior, one day, six weeks, twelve weeks and 24 weeks after PTA using a circular polarized extremity coil and a gradient echo sequence (TR/TE 600/6 ms, flip angle 30°, slice thickness 10 mm). Hemodynamic data, derived from the MR phase contrast sequence, allowed to calculate the degree of area stenosis of the lesion treated with PTA. These data were correlated with clinical hemodynamic parameters (ankle-brachial index and walking distance). Results: The mean grade of area stenosis was 69% ± 27% before PTA, 30% ± 20% one day, 29% ± 23% six weeks, 39% ± 17% twelve weeks and 42% ± 18% 24 weeks after PTA and correlated well with clinical data and the post angioplasty clinical course of the patients. Conclusions: Follow up measurements using MRVL are suitable to assess restenosis after PTA and allow quantifying the grade of recurrent stenosis as well as the hemodynamic consequences.

Visualization of microvasculature and thrombi by X-ray phase-contrast computed tomography in hepatocellular carcinoma

2016 ◽  
Vol 23 (2) ◽  
pp. 600-605 ◽  
Author(s):  
Jianbo Jian ◽  
Hao Yang ◽  
Xinyan Zhao ◽  
Ruijiao Xuan ◽  
Yujie Zhang ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Hepatocellular Carcinoma ◽  
Phase Contrast ◽  
Soft Tissues ◽  
Three Dimensional ◽  
X Ray ◽  
Density Distributions ◽  
Fine Structures ◽  
Tumor Growth And Metastasis ◽  
Micrometer Scale

Visualization of the microvascular network and thrombi in the microvasculature is a key step to evaluating the development of tumor growth and metastasis, and influences treatment selection. X-ray phase-contrast computed tomography (PCCT) is a new imaging technique that can detect minute changes of density and reveal soft tissues discrimination at micrometer-scale resolution. In this study, six human resected hepatocellular carcinoma (HCC) tissues were investigated with PCCT. A histological stain was added to estimate the accuracy of PCCT. The results showed that the fine structures of the microvasculature (measuring 30–100 µm) and thrombi in tiny blood vessels were displayed clearly on imaging the HCC tissues by PCCT. Moreover, density distributions of the thrombi were obtained, which could be reliably used to distinguish malignant from benign thrombi in HCC. In conclusion, PCCT can clearly show the three-dimensional subtle structures of HCC that cannot be detected by conventional absorption-based computed tomography and provides a new method for the imageology of HCC.

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