Non-interferometric accurate phase imaging via linear-convergence iterative optimization

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.

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Principles and Imaging Technologies of Magnetic Resonance Phase Imaging

ACTA BIOPHYSICA SINICA ◽

10.3724/sp.j.1260.2013.30059 ◽

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

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

Liver Cancer ◽

10.1159/000513704 ◽

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

Purpose: 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. Methods: 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. Results: 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 (>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). Conclusions: 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.

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Convergence rate analysis of an iterative algorithm for solving the multiple-sets split equality problem

Journal of Inequalities and Applications ◽

10.1186/s13660-019-2219-z ◽

2019 ◽

Vol 2019 (1) ◽

Author(s):

Shijie Sun ◽

Meiling Feng ◽

Luoyi Shi

Keyword(s):

Convergence Rate ◽

Iterative Algorithm ◽

Sufficient Conditions ◽

Linear Convergence ◽

Regularity Property ◽

Step Size ◽

Bounded Linear ◽

Split Equality Problem ◽

Linear Convergence Rate ◽

Equality Problem

Abstract This paper considers an iterative algorithm of solving the multiple-sets split equality problem (MSSEP) whose step size is independent of the norm of the related operators, and investigates its sublinear and linear convergence rate. In particular, we present a notion of bounded Hölder regularity property for the MSSEP, which is a generalization of the well-known concept of bounded linear regularity property, and give several sufficient conditions to ensure it. Then we use this property to conclude the sublinear and linear convergence rate of the algorithm. In the end, some numerical experiments are provided to verify the validity of our consequences.

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

Materials ◽

10.3390/ma14164384 ◽

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.

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Linear Convergence for Distributed Optimization Without Strong Convexity

2020 59th IEEE Conference on Decision and Control (CDC) ◽

10.1109/cdc42340.2020.9304381 ◽

2020 ◽

Author(s):

Xinlei Yi ◽

Shengjun Zhang ◽

Tao Yang ◽

Tianyou Chai ◽

Karl H. Johansson

Keyword(s):

Distributed Optimization ◽

Linear Convergence ◽

Strong Convexity

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

The Analyst ◽

10.1039/d0an01961e ◽

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.

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

Photonics ◽

10.3390/photonics8060177 ◽

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.

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