scholarly journals Quantifying myelin in crossing fibers using diffusion‐prepared phase imaging: Theory and simulations

2021 ◽  
Author(s):  
Michiel Cottaar ◽  
Wenchuan Wu ◽  
Benjamin C. Tendler ◽  
Zoltan Nagy ◽  
Karla Miller ◽  
...  
Keyword(s):  
Phase Imaging ◽  
Imaging Theory ◽  
Crossing Fibers

Fourier imaging of phase information in scanning and conventional optical microscopes

1980 ◽  
Vol 295 (1415) ◽  
pp. 513-536 ◽  
Keyword(s):  
Phase Contrast ◽  
Phase Imaging ◽  
Phase Information ◽  
Scanning Microscope ◽  
Detector Plane ◽  
Fourier Imaging ◽  
Imaging Theory ◽  
Imaging Performance

The imaging performance of scanning microscopes may be improved by introducing a pinhole in the detector plane, thus forming a confocal (or type 2) scanning microscope. A general imaging theory is developed from which the performance of scanning and conventional microscopes may be investigated. Various methods of obtaining phase imaging are considered, including the effects of defocus, Zernike phase contrast, and interference and resonant microscopy.

Reconstruction of electron holograms recorded in a non-FEG, non-biprism TEM

1995 ◽  
Vol 53 ◽  
pp. 618-619
Author(s):  
Z.L. Wang
Keyword(s):  
Electron Microscope ◽  
Single Crystal ◽  
Experimental Technique ◽  
Transmission Electron Microscope ◽  
The Other ◽  
Electron Holography ◽  
Transmission Electron ◽  
Coherent Sources ◽  
Imaging Theory ◽  
Normal Specimen

An experimental technique for performing electron holography using a non-FEG, non-biprism transmission electron microscope (TEM) has been introduced by Ru et al. A double stacked specimens, one being a single crystal foil and the other the specimen, are loaded in the normal specimen position in TEM. The single crystal, which is placed onto the specimen, is responsible to produce two beams that are equivalent to two virtual coherent sources illuminating the specimen beneath, thus, permitting electron holography of the specimen. In this paper, the imaging theory of this technique is described. Procedures are introduced for digitally reconstructing the holograms.

Velocity Window for Detection of Flow with MR Phase Imaging

1996 ◽  
Vol 34 (6) ◽  
pp. 729
Author(s):  
Tae Hwan Lim ◽  
Nuno J Tavares ◽  
Nola M Hylton ◽  
Charles B Higgins
Keyword(s):  
Phase Imaging

99mTc-DPD SPECT/CT for localisation of inflammatory and chronic osteoarthritis of the foot and ankle

2016 ◽  
Vol 55 (04) ◽  
pp. 145-150 ◽  
Author(s):  
Lutz Freudenberg ◽  
Hinrich Wieder ◽  
Jens Stollfuss
Keyword(s):  
Bone Metabolism ◽  
Late Phase ◽  
Blood Pool ◽  
Phase Imaging ◽  
Bone Imaging ◽  
Foot And Ankle ◽  
Planar Imaging ◽  
Selective Treatment ◽  
Complex Anatomy ◽  
Three Phase

SummaryAim: The precise localisation of osteoarthritic and inflammatory changes is crucial for selective treatment planning of radiosynovectomy (RSV). The present study evaluated the diagnostic accuracy of planar bone imaging and SPECT for the detection of pathological bone metabolism and inflammation in joints of the foot and ankle, compared with SPECT/CT. Patients, methods: 39 patients (mean age 65.6 ± 11.1 years) with suspected inflammatory osteoarthritis underwent SPECT/CT of the feet. After injection of approximately 500 MBq 99mTc DPD, all patients had three-phase planar bone imaging and late-phase hybrid SPECT/CT. late-phase SPECT, and CT of the foot. Increased bone metabolism and blood-pool was assigned to the respective joint of the fore-, mid-, and hindfoot, using SPECT/CT as the reference standard. Results: Overall, SPECT had a higher sensitivity than planar imaging (0.80 vs 0.68, n.s.). The advantage of SPECT was most obvious in the anatomically complex midfoot area (0.63 vs 0.26, p < 0.05) and less obvious in the forefoot (0.85 vs 0.79, n.s.) and hindfoot (0.89 vs 0.89, n.s.). The overall concordance (Cohen`s Kappa) between SPECT/CT and planar (late-phase) imaging and SPECT was high for the forefoot and the hindfoot (planar: 0.78/0.81; SPECT 0.86/0.88) and comparatively low for the midfoot (planar: 0.27; SPECT 0.61). Conclusion: SPECT was significantly superior to planar bone imaging for the detection of joint lesions in the midfoot. The differences between SPECT and planar imaging in the fore- and hindfoot were not significant, most likely due to the inherently less complex anatomy. Compared with SPECT alone, a benefit from the use of SPECT/CT can be observed in the midfoot region where it facilitates the identification of the correct joint for RSV.

Principles and Imaging Technologies of Magnetic Resonance Phase Imaging

2013 ◽  
Vol 29 (6) ◽  
pp. 407
Author(s):  
Yaxian LOU ◽  
Gang ZHENG ◽  
Li CAO ◽  
Zhiying PAN ◽  
Tiezhu ZHAO ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Phase Imaging ◽  
Imaging Technologies

scholarly journals MRI Features for Predicting Microvascular Invasion of Hepatocellular Carcinoma: A Systematic Review and Meta-Analysis

Liver Cancer ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 94-106
Author(s):  
Seung Baek Hong ◽  
Sang Hyun Choi ◽  
So Yeon Kim ◽  
Ju Hyun Shim ◽  
Seung Soo Lee ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Tumor Size ◽  
Meta Analysis ◽  
Diagnostic Odds Ratio ◽  
Microvascular Invasion ◽  
Hepatobiliary Phase ◽  
Phase Imaging ◽  
Arterial Enhancement ◽  
Mri Features ◽  
Peritumoral Enhancement

<b><i>Purpose:</i></b> Microvascular invasion (MVI) is an important prognostic factor in patients with hepatocellular carcinoma (HCC). However, the reported results of magnetic resonance imaging (MRI) features for predicting MVI of HCC are variable and conflicting. Therefore, this meta-analysis aimed to identify the significant MRI features for MVI of HCC and to determine their diagnostic value. <b><i>Methods:</i></b> Original studies reporting the diagnostic performance of MRI for predicting MVI of HCC were identified in MEDLINE and EMBASE up until January 15, 2020. Study quality was assessed using QUADAS-2. A bivariate random-effects model was used to calculate the meta-analytic pooled diagnostic odds ratio (DOR) and 95% confidence interval (CI) for each MRI feature for diagnosing MVI in HCC. The meta-analytic pooled sensitivity and specificity were calculated for the significant MRI features. <b><i>Results:</i></b> Among 235 screened articles, we found 36 studies including 4,274 HCCs. Of the 15 available MRI features, 7 were significantly associated with MVI: larger tumor size (&#x3e;5 cm) (DOR = 5.2, 95% CI [3.0–9.0]), rim arterial enhancement (4.2, 95% CI [1.7–10.6]), arterial peritumoral enhancement (4.4, 95% CI [2.8–6.9]), peritumoral hypointensity on hepatobiliary phase imaging (HBP) (8.2, 95% CI [4.4–15.2]), nonsmooth tumor margin (3.2, 95% CI [2.2–4.4]), multifocality (7.1, 95% CI [2.6–19.5]), and hypointensity on T1-weighted imaging (T1WI) (4.9, 95% CI [2.5–9.6]). Both peritumoral hypointensity on HBP and multifocality showed very high meta-analytic pooled specificities for diagnosing MVI (91.1% [85.4–94.8%] and 93.3% [74.5–98.5%], respectively). <b><i>Conclusions:</i></b> Seven MRI features including larger tumor size, rim arterial enhancement, arterial peritumoral enhancement, peritumoral hypointensity on HBP, nonsmooth margin, multifocality, and hypointensity on T1WI were significant predictors for MVI of HCC. These MRI features predictive of MVI can be useful in the management of HCC.

scholarly journals An Insight into Amorphous Shear Band in Magnetorheological Solid by Atomic Force Microscope

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4384
Author(s):  
Mohd Aidy Faizal Johari ◽  
Asmawan Mohd Sarman ◽  
Saiful Amri Mazlan ◽  
Ubaidillah U ◽  
Nur Azmah Nordin ◽  
...  
Keyword(s):  
Stress Relaxation ◽  
Shear Band ◽  
Shear Bands ◽  
Test Duration ◽  
Phase Imaging ◽  
Force Microscopy ◽  
Atomic Force ◽  
The Matrix ◽  
Relaxation Stress ◽  
Band Deformation

Micro mechanism consideration is critical for gaining a thorough understanding of amorphous shear band behavior in magnetorheological (MR) solids, particularly those with viscoelastic matrices. Heretofore, the characteristics of shear bands in terms of formation, physical evolution, and response to stress distribution at the localized region have gone largely unnoticed and unexplored. Notwithstanding these limitations, atomic force microscopy (AFM) has been used to explore the nature of shear band deformation in MR materials during stress relaxation. Stress relaxation at a constant low strain of 0.01% and an oscillatory shear of defined test duration played a major role in the creation of the shear band. In this analysis, the localized area of the study defined shear bands as varying in size and dominantly deformed in the matrix with no evidence of inhibition by embedded carbonyl iron particles (CIPs). The association between the shear band and the adjacent zone was further studied using in-phase imaging of AFM tapping mode and demonstrated the presence of localized affected zone around the shear band. Taken together, the results provide important insights into the proposed shear band deformation zone (SBDZ). This study sheds a contemporary light on the contentious issue of amorphous shear band deformation behavior and makes several contributions to the current literature.

scholarly journals Simultaneous measurement of neurite and neural body mass accumulation via quantitative phase imaging

The Analyst ◽  
2021 ◽  
Author(s):  
Soorya Pradeep ◽  
Tasmia Tasnim ◽  
Huanan Zhang ◽  
Thomas A. Zangle
Keyword(s):  
Body Mass ◽  
Biomass Production ◽  
Simultaneous Measurement ◽  
Neural Differentiation ◽  
Phase Imaging ◽  
Quantitative Phase Imaging ◽  
Quantitative Phase ◽  
Mass Accumulation

Quantitative phase imaging (QPI) used to quantify the mass of soma (cell bodies) and neurites as well as the rates of biomass production due to neurite maturation and formation during neural differentiation.

scholarly journals Computational Method for Wavefront Sensing Based on Transport-Of-Intensity Equation

Photonics ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 177
Author(s):  
Iliya Gritsenko ◽  
Michael Kovalev ◽  
George Krasin ◽  
Matvey Konoplyov ◽  
Nikita Stsepuro
Keyword(s):  
A Priori ◽  
Spherical Wave ◽  
Computational Method ◽  
Optical Systems ◽  
Radius Of Curvature ◽  
Imaging Method ◽  
Wavefront Sensing ◽  
Phase Imaging ◽  
Transport Of Intensity Equation ◽  
Priori Information

Recently the transport-of-intensity equation as a phase imaging method turned out as an effective microscopy method that does not require the use of high-resolution optical systems and a priori information about the object. In this paper we propose a mathematical model that adapts the transport-of-intensity equation for the purpose of wavefront sensing of the given light wave. The analysis of the influence of the longitudinal displacement z and the step between intensity distributions measurements on the error in determining the wavefront radius of curvature of a spherical wave is carried out. The proposed method is compared with the traditional Shack–Hartmann method and the method based on computer-generated Fourier holograms. Numerical simulation showed that the proposed method allows measurement of the wavefront radius of curvature with radius of 40 mm and with accuracy of ~200 μm.

scholarly journals Diffusion interactions between crossing fibers of the brain

2021 ◽  
Vol 86 (1) ◽  
pp. 429-441
Author(s):  
Sergey V. Buldyrev ◽  
Xiangyi Meng ◽  
Timothy G. Reese ◽  
Farzad Mortazavi ◽  
Douglas L. Rosene ◽  
...  
Keyword(s):  
Crossing Fibers ◽  
The Brain
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