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In order to adapt to the rapid development of deep space exploration, pulsar navigation and space astronomical observation technology, the development of high-efficiency and high-performance X-ray space telescopes has become one of the hotspots for research in the fields of autonomous spacecraft navigation and astronomical observation. Since the X-ray multilayer nested mirror shells are thin-walled and deformable cylindrical structures with high requirements for surface shape accuracy, a slight change in the position or surface shape will lead to a reduction in the focusing imaging quality, so it is necessary to develop a high-precision assembly and adjustment system based on closed-loop real-time monitoring. In this paper, a multi-layer nested space ray telescope assembly and adjustment system with online monitoring feedback is developed, and a method for precision assembly and adjustment of multi-layer nested mirror shells based on online real-time detection and feedback is proposed, which specifically includes key innovative assembly technologies such as three-dimensional face shape measurement, flexible vacuum adsorption, precision adjustment that have been broken through in the process, and the imaging quality of the focused spot of the mirror shells is evaluated and analyzed in the end. The results of the experiment indicate that the assembly and adjustment of the multilayer nested mirror shells can effectively complete the high-precision assembly, and the relevant results can provide a certain reference significance for the further enhancement of the assembly and adjustment performance of the multilayer nested mirror shells. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate deep learning reconstruction (DLR)-based accelerated rectal magnetic resonance imaging (MRI) compared with standard MRI. Materials and methods: Patients with biopsy-confirmed rectal adenocarcinoma between November/2022 and May/2023 in a single centre were prospectively enrolled for an intra-individual comparison between standard fast spin-echo (FSEstandard) and DLR-based FSE (FSEDL) sequences. Quantitative and qualitative image quality metrics of the pre-therapeutic MRIs were evaluated in all patients; diagnostic performance and evaluating time for T-staging, N-staging, extramural vascular invasion (EMVI), and mesorectal fascia (MRF) status was further analysed in patients undergoing curative surgery, with histopathologic results as the diagnostic gold standard. Results: A total of 117 patients were enrolled, with 60 patients undergoing curative surgery. FSEDL reduced the acquisition time by 65% than FSEstandard. FSEDL exhibited higher signal-to-noise ratios, contrast-to-noise ratio, and subjective scores (noise, tumour margin clarity, visualisation of bowel wall layering and MRF, overall image quality, and diagnostic confidence) than FSEstandard (p < 0.001). Reduced artefacts were observed in FSEDL for patients without spasmolytics (p < 0.05). FSEDL provided higher T-staging accuracy by junior readers than FSEstandard (reader 1, 58.33% vs 70.00%, p = 0.016; reader 3, 60.00% vs 76.67%, p = 0.021), with similar N-staging, EMVI, and MRF performance. No significant difference was observed for senior readers. FSEDL exhibited shorter diagnostic time in all readers' T-staging and overall evaluation, and junior readers' EMVI and MRF (p < 0.05). Conclusion: FSEDL provided improved image quality, reading time, and junior radiologists' T-staging accuracy than FSEstandard, while reducing the acquisition time by 65%. Clinical relevance statement: DLR is clinically applicable for rectal MRI, providing improved image quality with shorter scanning time, which may ease the examination burden. It is beneficial for diagnostic optimisation in improving junior radiologists' T-staging accuracy and reading time. Key Points: The rising incidence of rectal cancer has demanded enhanced efficiency and quality in imaging examinations. FSEDLdemonstrated superior image quality and had a 65% reduced acquisition time. FSEDLcan improve the diagnostic accuracy of T-staging and reduce the reading time for assessing rectal cancer. [ABSTRACT FROM AUTHOR]

The key indicator of a grazing incidence focusing mirror's imaging quality is its angular resolution, which is significantly influenced by its surface shape distribution error. In this paper, we propose a method for the prediction of grazing incidence focusing mirror imaging quality based on accurate modelling of the surface shape accuracy for the whole assembly process. Firstly, the three-dimensional surface shape distribution error of the inner surface of the focusing mirror is reconstructed based on measured point cloud data, and the changes in the surface shape induced by suspension gravity and the adhesive curing shrinkage force are obtained through simulation, and then an accurate geometric digital twin model based on the characterisation of its surface shape accuracy is established. Finally, a study on the quantitative prediction of the angular resolution of its imaging quality is performed. The results show that the surface shape error before assembly has the greatest influence on the imaging quality; the difference in angular resolution between the two suspension methods under the influence of gravity is approximately 2.1″, and the angular resolution decreases by about 4.2″ due to adhesive curing. This method can provide effective support for the prediction of the imaging quality of grazing incidence focusing mirrors. [ABSTRACT FROM AUTHOR]

Electron beam (e‐beam) with a small spot size is the key to produce microfocus x‐ray source. The spot size of the e‐beam can be controlled by changing the aperture angle at the target, and the focus size of the microfocus x‐ray source is changed accordingly. At the same time, the SNR (Signal‐to‐Noise Ratio) of the image is reduced because the aperture produces secondary x‐ray, which interferes with the x‐ray imaging. In this paper, the aperture size and its position are optimized for getting the smallest spot size of the e‐beam, and the experimental results show that the resolution is 0.8 μm with the aperture size of 0.5 mm. In addition, this paper also presents that the image's SNR can be improved by coating carbon film on the back surface of the aperture. [ABSTRACT FROM AUTHOR]

A four-group mechanically compensated continuous-zoom microscope is proposed and designed based on the theory of continuous zoom. The system addresses the limitations of traditional continuous-zoom microscopes, including a small zoom ratio, a short working distance, and the loss of details during 2D–3D switching. The system has a magnification of 0.6×~6.0× under two-dimensional observation, adapts to two-third-inch sensors, has a working distance of 130 mm, and adds a 360-degree rotatable beamsplitter for three-dimensional full-field-of-view observation. The magnification, numerical aperture, and sensor dimensions remain unchanged under both two-dimensional and three-dimensional observation. The design results demonstrate that the system is capable of achieving a high zoom ratio of 10× while maintaining a high level of imaging quality in both two-dimensional and three-dimensional modes. The MTF curves for each magnification are in close proximity to the diffraction limit, the spot diagrams are smaller than the airy disk range, and the zoom cam curves are smooth with no inflection points. Furthermore, the system negates the visual discrepancies and loss of detail that arise when switching observation modes due to alterations in system magnification and numerical aperture, thereby broadening the scope of applications for continuous-zoom microscopes. [ABSTRACT FROM AUTHOR]

In the treatment of uterine fibroids with ultrasound-guided high-intensity focused ultrasound (HIFU), water balloons are considered to be a valuable aid for improving safety and efficiency. However, the water balloons worsen the pathway for acoustic transmission, causing degraded performance both in ultrasound therapy and in ultrasound imaging. This study was aimed at establishing a protocol to evaluate the effects of the water balloon. Simulations and experiments were carefully conducted to quantitatively investigate the effects of water ballons on the efficiency of HIFU energy delivery and on the quality of ultrasound guiding images. More specifically, HIFU-induced temperature increases in the focal region, together with spatial resolution, contrast and signal-to-noise ratio in the ultrasound guiding images, were compared under the conditions with and without the water balloon. Experiment results revealed that the use of water balloons led to decreases in temperature up to 10ºC within the focal region in some specific situations, but the quality of the guiding images was relatively less affected. The study provided knowledge on what influence the water balloon could have in ultrasound-guided HIFU treatment; it also established a practical and standardized evaluation scheme for further optimizing the water balloon, for example, its material and internal liquid compositions. This study can potentially help improve the efficiency and safety of treating uterine fibroids with ultrasound-guided HIFU systems. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Data Acquisition & Processing / Shu Ju Cai Ji Yu Chu Li is the property of Editorial Department of Journal of Nanjing University of Aeronautics & Astronautics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The key indicator of a grazing incidence focusing mirror’s imaging quality is its angular resolution, which is significantly influenced by its surface shape distribution error. In this paper, we propose a method for the prediction of grazing incidence focusing mirror imaging quality based on accurate modelling of the surface shape accuracy for the whole assembly process. Firstly, the three-dimensional surface shape distribution error of the inner surface of the focusing mirror is reconstructed based on measured point cloud data, and the changes in the surface shape induced by suspension gravity and the adhesive curing shrinkage force are obtained through simulation, and then an accurate geometric digital twin model based on the characterisation of its surface shape accuracy is established. Finally, a study on the quantitative prediction of the angular resolution of its imaging quality is performed. The results show that the surface shape error before assembly has the greatest influence on the imaging quality; the difference in angular resolution between the two suspension methods under the influence of gravity is approximately 2.1″, and the angular resolution decreases by about 4.2″ due to adhesive curing. This method can provide effective support for the prediction of the imaging quality of grazing incidence focusing mirrors.

A four-group mechanically compensated continuous-zoom microscope is proposed and designed based on the theory of continuous zoom. The system addresses the limitations of traditional continuous-zoom microscopes, including a small zoom ratio, a short working distance, and the loss of details during 2D–3D switching. The system has a magnification of 0.6×~6.0× under two-dimensional observation, adapts to two-third-inch sensors, has a working distance of 130 mm, and adds a 360-degree rotatable beamsplitter for three-dimensional full-field-of-view observation. The magnification, numerical aperture, and sensor dimensions remain unchanged under both two-dimensional and three-dimensional observation. The design results demonstrate that the system is capable of achieving a high zoom ratio of 10× while maintaining a high level of imaging quality in both two-dimensional and three-dimensional modes. The MTF curves for each magnification are in close proximity to the diffraction limit, the spot diagrams are smaller than the airy disk range, and the zoom cam curves are smooth with no inflection points. Furthermore, the system negates the visual discrepancies and loss of detail that arise when switching observation modes due to alterations in system magnification and numerical aperture, thereby broadening the scope of applications for continuous-zoom microscopes.

This study mitigated the challenge of head and neck CT angiography by IPA-based time-resolved imaging of contrast kinetics. To this end, 627 cerebral hemorrhage patients with dizziness, brain aneurysm, stroke, or hemorrhagic stroke diagnosis were randomly categorized into three groups, namely, the original dataset (450), verification group (112), and in vivo testified group (65), in the Affiliated BenQ Hospital of Nanjing Medical University. In the first stage, seven risk factors were assigned: age, CTA tube voltage, body surface area, heart rate per minute, cardiac output blood per minute, the actual injected amount of contrast media, and CTA delayed trigger timing. The expectation value of the semi-empirical formula was the CTA number of the patient's left artery (LA). Accordingly, 29 items of the first-order nonlinear equation were calculated via the inverse problem analysis (IPA) technique run in the STATISTICA 7.0 program, yielding a loss function and variance of 3.1837 and 0.8892, respectively. A dimensionless AT was proposed to imply the coincidence, with a lower AT indicating a smaller deviation between theoretical and practical values. The derived formula was confirmed for the verification group of 112 patients, reaching high coincidence, with average ATavg and standard deviation values of 3.57% and 3.06%, respectively. In the second stage, the formula was refined to find the optimal amount of contrast media for the CTA number of LA approaching 400. Finally, the above procedure was applied to head and neck CTA images of the third group of 65 patients, reaching an average CTA number of LA of 407.8 ± 16.2 and finding no significant fluctuations. [ABSTRACT FROM AUTHOR]

Copyright of Die Radiologie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Die Radiologie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

As the basis of machine vision, the biomimetic image sensing devices are the eyes of artificial intelligence. In recent years, with the development of two-dimensional (2D) materials, many new optoelectronic devices are developed for their outstanding performance. However, there are still little sensing arrays based on 2D materials with high imaging quality, due to the poor uniformity of pixels caused by material defects and fabrication technique. Here, we propose a 2D MoS2 sensing array based on artificial neural network (ANN) learning. By equipping the MoS2 sensing array with a "brain" (ANN), the imaging quality can be effectively improved. In the test, the relative standard deviation (RSD) between pixels decreased from about 34.3% to 6.2% and 5.49% after adjustment by the back propagation (BP) and Elman neural networks, respectively. The peak signal to noise ratio (PSNR) and structural similarity (SSIM) of the image are improved by about 2.5 times, which realizes the re-recognition of the distorted image. This provides a feasible approach for the application of 2D sensing array by integrating ANN to achieve high quality imaging. [ABSTRACT FROM AUTHOR]

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In the automatic sorting process, overlapping translucent and flexible workpieces on the conveyor belt, blurring the imaging edge features of translucent and flexible workpieces is a challenge to locate the upper and lower workpieces spatially, we propose a method for locating translucent and flexible workpieces spatially under the overlapping environment in conjunction with the most common automatic sorting of translucent and flexible workpieces such as infusion tube drip buckets. Firstly, we propose a rectangular surface light source based on 650 nm band and monocular CCD for imaging translucent workpieces such as infusion tube drip buckets and optimize the imaging parameters. Secondly, we study a feature matching recognition algorithm for flexible workpieces that are prone to deformation, construct a mapping relationship between the position of overlapping layers and imaging quality of translucent and flexible workpieces such as infusion tube drip buckets based on clarity and information entropy, and establish The mapping relationship between the position of the overlapping layers and the imaging quality of translucent and flexible workpieces such as infusion tube drip buckets is constructed based on clarity and information entropy, and a local spatial coordinate conversion model is established. Finally, the spatial positioning coordinates of overlapping and non-overlapping translucent and flexible workpieces in the local coordinate system are identified, and the results show that the imaging method and theory can be effectively applied to the identification of overlapping and spatial positioning coordinates in the automatic sorting of translucent workpieces such as infusion tube drip buckets. [ABSTRACT FROM AUTHOR]

Applying the convolutional neural network to ghost imaging to form network ghost imaging (netGI), one can improve the image quality of computational ghost imaging (CGI). The images reconstructed by CGI and the original images are used as the training set to generate the neural network, and the sampling rate of the CGI is taken as the sampling rate of netGI. When the sampling rate of CGI is consistent with that of netGI, the quality of the reconstructed image is the best, and the values of the peak signal-to-noise ratio (PSNR) and structural similarity measurement (SSIM) indicators reach their peaks. For the low sample rate γ = 0.1, the quality of the reconstructed image is significantly improved when the sampling rate of netGI matches that of CGI. The PSNR increases by 109.7%, and the SSIM increases by 300%. This method effectively solves the problem of reconstructing high-quality images under a low sampling rate. It has wide application prospects in the rapid CGI application of low-dose detection, especially in biomedical detection. [ABSTRACT FROM AUTHOR]

This study mitigated the challenge of head and neck CT angiography by IPA-based time-resolved imaging of contrast kinetics. To this end, 627 cerebral hemorrhage patients with dizziness, brain aneurysm, stroke, or hemorrhagic stroke diagnosis were randomly categorized into three groups, namely, the original dataset (450), verification group (112), and in vivo testified group (65), in the Affiliated BenQ Hospital of Nanjing Medical University. In the first stage, seven risk factors were assigned: age, CTA tube voltage, body surface area, heart rate per minute, cardiac output blood per minute, the actual injected amount of contrast media, and CTA delayed trigger timing. The expectation value of the semi-empirical formula was the CTA number of the patient’s left artery (LA). Accordingly, 29 items of the first-order nonlinear equation were calculated via the inverse problem analysis (IPA) technique run in the STATISTICA 7.0 program, yielding a loss function and variance of 3.1837 and 0.8892, respectively. A dimensionless AT was proposed to imply the coincidence, with a lower AT indicating a smaller deviation between theoretical and practical values. The derived formula was confirmed for the verification group of 112 patients, reaching high coincidence, with average ATavg and standard deviation values of 3.57% and 3.06%, respectively. In the second stage, the formula was refined to find the optimal amount of contrast media for the CTA number of LA approaching 400. Finally, the above procedure was applied to head and neck CTA images of the third group of 65 patients, reaching an average CTA number of LA of 407.8 ± 16.2 and finding no significant fluctuations.

Introduction: Image optimisation is essential for acquisition of quality images in ultrasound and critical to the diagnostic ability of the examination. These skills are taught to sonography students early in their education, but research has found that retention of non-rehearsed knowledge decreases significantly after a year. The aim of this study was to determine which optimisation tools (knobology) final year sonography students use, how often and why they chose to adjust parameters and assess barriers to optimisation of knobology tools. Methods: A prospective study using data from an anonymous online survey of 34 final year sonography students. Results: Survey results showed that 19/34 (55%) of students "frequently" optimise all Doppler settings and 23/34 (67%) of students "frequently" optimise basic parameter settings (depth, focus, time gain compensation). Time constraints (24/34 (70%)) and loss of gained knowledge of sonography principles and instrumentation (17/34 (50%)) were the major barriers to the use of knobology. The majority 28/34 (82%) believed they would benefit from further training. Conclusion: This study demonstrates that although most students are optimising settings to improve image quality, sonography principles and instrumentation knowledge loss and time constraints prevent students from maximising machine capabilities. This study supports the need for further training prior to final year clinical placement. [ABSTRACT FROM AUTHOR]

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The purpose of this study was to compare the scan time, image quality and radiation dose of CT urograms (CTU) using a split vs. single bolus contrast media injection technique. A total of 241 consecutive CTUs performed between August 2019-February 2020 were retrospectively reviewed. There were three study groups: Group 1, p = 0.006). Mean scan time was significantly lower in group 3 (678 s) than in groups 1 (1046 s) and 2 (978 s) (p < 0.0001). There was no association between groups and image quality (p = 0.13). DLP was higher in group 3 (1422 ± 837 mGy·cm) than in groups 1 (1041 ± 531 mGy·cm) and 2 (1137 ± 646 mGy·cm) (p = 0.003). In conclusion, single bolus CTU resulted in significantly fewer repeat phases and faster scan time at the expense of a slightly higher radiation dose.

Abstract Purpose To compare integrated slice-specific dynamic shimming (iShim) diffusion weighted imaging (DWI) and single-shot echo-planar imaging (SS-EPI) DWI in image quality and pathological characterization of rectal cancer. Materials and methods A total of 193 consecutive rectal tumor patients were enrolled for retrospective analysis. Among them, 101 patients underwent iShim-DWI (b = 0, 800, and 1600 s/mm2) and 92 patients underwent SS-EPI-DWI (b = 0, and 1000 s/mm2). Qualitative analyses of both DWI techniques was performed by two independent readers; including adequate fat suppression, the presence of artifacts and image quality. Quantitative analysis was performed by calculating standard deviation (SD) of the gluteus maximus, signal intensity (SI) of lesion and residual normal rectal wall, apparent diffusion coefficient (ADC) values (generated by b values of 0, 800 and 1600 s/mm2 for iShim-DWI, and by b values of 0 and 1000 s/mm2 for SS-EPI-DWI) and image quality parameters, such as signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of primary rectal tumor. For the primary rectal cancer, two pathological groups were divided according to pathological results: Group 1 (well-differentiated) and Group 2 (poorly differentiated). Statistical analyses were performed with p

• A deep learning method improves image quality for high-speed 4DCT reconstruction. • It improves radiomics reproducibility between two reconstruction algorithms. • It is computationally efficient and may be integrated into any CT system. Hybrid iterative reconstruction (HIR) is the most commonly used algorithm for four-dimensional computed tomography (4DCT) reconstruction due to its high speed. However, the image quality is worse than that of model-based iterative reconstruction (MIR). Different reconstruction methods affect the stability of radiomics features. Herein, we developed a deep learning method to improve the quality and radiomics reproducibility of the high-speed reconstruction. The 4DCT images of 70 patients were reconstructed using both the HIR and MIR algorithms. A cycle-consistent adversarial network was adopted to learn the mapping from HIR to MIR, and then generate synthetic MIR (sMIR) images from HIR. The performance was evaluated using the testing set (10 patients). The total reconstruction times for the HIR, MIR, and proposed sMIR images were approximately 2.5, 15, and 3.1 mins, respectively. The quality of sMIR images was close to that of MIR and was superior to that of HIR images, with noise reduced by 45–77% and contrast-to-noise ratio improved by 91–296%. The concordance correlation coefficients (CCC) of radiomic features improved from 0.89 ± 0.15 for HIR to 0.97 ± 0.07 for the proposed sMIR. The percentage of reproducible features (CCC ≥ 0.85) increased from 76.08% for HIR to 95.86% for sMIR, with an improvement of 19.78%. Compared to existing HIR algorithm , the proposed method improves the image quality and radiomics reproducibility of 4DCT images under high-speed reconstruction. It is computationally efficient and has potential to be integrated into any CT system. [ABSTRACT FROM AUTHOR]

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AIM: To evaluate the possibilities of flow detection using high resolution flow (HR Flow) and Glazing Flow technique in patients with liver parenchymal changes and flow changes in comparison to color-coded Doppler sonography (CCDS). MATERIAL AND METHODS: All examinations were performed using a multi frequency matrix convex probe with high resolution technique (SC6-1U/Resona7, Mindray, Shenzhen, China) by one experienced examiner to evaluate the venous, portal venous and arterial liver flow with digital documentation of the dynamic flow parameters like peak systolic flow, end-diastolic flow and resistance index. For liver parenchymal stiffness changes shear wave elastography was performed with at least 10 measurements. By two independent readers an elevation was performed to evaluate the image quality and the degree of flow artefacts, from 0 = not available to 5 points with excellent image quality without flow artefacts. RESULTS: All 40 patients (24 men, 16 women, age 27–83 years, mean 56±5 years) showed morphology changes from B-Mode of the liver parenchyma to inhomogeneous tissue with higher stiffness evaluated by the shear wave elastography (1.45 m/s up to 2.79 m/s±1.79 m/s, considering F1 up to F4 fibrosis) and in 15 cases histopathologically proven liver cirrhosis. In 9 cases after non-acute thrombosis flow reduction of the portal vein was the reason for the diameter less than 5 mm. Flow parameters for the venous flow were between 8 cm/s up to 29 cm/s, mean 14±4 cm/s, for the hepatic portal vein 5 cm/s up to 57 cm/s, mean 17±5 cm/s, for the hepatic artery systolic flow between 50 cm/s up to 127±33 cm/s, end-diastolic flow from 22 cm/s up to 47±8 cm/s. Resistance index for the hepatic artery was between 0.41 up to 0.73, mean 0.67±0.25. The image quality for CCDS over all cases was evaluated for CCDS between 1 up to 4. The mean quality was 2.5±0.5, for HR Flow in combination with Glazing Flow 3±0.5, with significant differences for the 2 readers (P < 0.01). CONCLUSION: Combination of HR Flow with Glazing Flow could be helpful to evaluate morphological und hemodynamic changes of liver arterial flow, portal venous and venous flow. Reduction of flow artefacts in combination with a higher image quality could be helpful for optimizing the digital measurements also for follow up examinations. [ABSTRACT FROM AUTHOR]

AIM: To investigate the effect of inclination and eccentricity of intraocular lens(IOL),on optical imaging quality via wavefront aberration optical path system.METHODS: The spherical IOL Sensar AR40e, the aspherical monofocal IOL Tecnis ZA9003, and the aspheric multifocal IOL Tecnis ZM900 were measured at the center of the center using a laboratory-built Hartmann-Shack IOL wavefront aberration path system at 5.0mm simulated pupil diameter. 0, 0.2, 0.4, 0.6, 0.8mm, the effect on the optical imaging quality when tilting 5°, 10°, 15°, 20°, 25° to the nasal side and the temporal side, and quantitative imaging quality by high-order aberration and modulation transfer function.RESULTS: The Temnis ZA9003 MTF value was higher than AR40e and Tecnis ZM900 when inclinationed within 5°, while the three IOL MTF values were significantly different when inclinationed 5°, 10°, 15°, and 20°. Tecnis ZA9003 The IOL inclination angle was significantly positively correlated with the coma(r=0.842, Pr=0.229, P=0.241). The three IOL MTF values were obtained when the eccentricity was 0.6 and 0.8 mm. Significant differences(both PCONCLUSION: When the inclination of aspheric IOL(-0.27μm spherical aberration)is less than 5°and the eccentricity is less than 0.4mm, aspherical IOL has a better imaging quality than that of spherical IOL. Tecnis ZM900 IOL has a lower optical imaging quality than that of spherical and aspheric IOL when the eccentricity of IOL is more than 0.4mm.

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Objective: To explore the diagnostic significance of three-dimensional hysterosalpingography combined with two-dimensional vaginal ultrasound in women with infertility. Methods: From March 2019 to October 2020, 90 cases of female patients with infertility diagnosed and treated in Second Affiliated Hospital of Xi'an Medical College and Shaanxi Provincial People's Hospital were selected as the research objects. All patients were given three-dimensional hysterosalpingography combined with two-dimensional vaginal ultrasound, recorded the imaging quality and pain. X-ray hysterosalpingography was used the gold standard to judge the diagnostic value. Results: During the examination, the pain score of patients with three-dimensional contrast-enhanced ultrasound was higher than that of two-dimensional ultrasound, and compared the difference were not statistically significant (P>0.05). The excellent and good imaging quality rate of three-dimensional contrast-enhanced ultrasound is 100.0 % (90/90), which is higher than that of two-dimensional ultra- sound of 93.3 % (84/90). The difference is statistically significant(P<0.05). In the 90 patients, the three-dimensional contrast-enhanced ultrasonography judged that the periovarian tissue were diffused in 59 cases at grade 1, 16 cases in grade 2, 10 cases in grade 3, and 5 cases in grade 4. Three-dimensional hysterosalpingography combined with two-dimensional vaginal ultrasound judged that the fallopian tubes were unobstructed in 55 cases, unobstructed in 25 cases, and obstructed in 10 cases. X-ray hysterosalpingography determined that the fallopian tubes were unobstructed in 53 cases, unobstructed in 26 cases, and obstructed in 11 cases. The diagnostic accuracy of three-dimensional hysterosalpingography combined with vaginal two-dimensional ultrasound was 96.7 %(87/90). Conclusion: The application of three-dimensional hysterosalpingography combined with two-dimensional vaginal ultrasound in infertile women will not increase the patient's pain, and can improve the imaging quality, and is also conducive to the reasonable evaluation and judgment of the patient's tubal patency. [ABSTRACT FROM AUTHOR]

Objective: To investigate the effects of low-dose and conventional dose spiral CT dynamic scanning on imaging quality, radiation dose and satisfaction of patients with chronic obstructive pulmonary disease (COPD). Methods: 88 patients with initial diagnosis of COPD who were admitted in our hospital from January 2019 to January 2020 were selected. Single and even number grouping method was used to divide the patients into low-dose group and conventional group, 44 cases in each group. Low dose spiral CT dynamic scanning was used in low-dose group, conventional dose spiral CT dynamic scanning was used in conventional group. The radiation dose, imaging quality and diagnosis results of COPD were compared between the two groups. The satisfaction scores of the two groups were compared. Results: CT dose weighted index (CTDIW), dose length product (DLP) and effective radiation dose (ED) in low-dose group were significantly lower than those of conventional group, the difference was statistically significant (P<0.05). The excellent rate of imaging quality in conventional group was significantly higher than that of low-dose group (P<0.05), but there was no significant difference in the effective rate of imaging quality between the two groups(P>0.05). There was no significant difference in sensitivity and specificity between low-dose group and conventional group (P>0.05). The satisfaction score of low-dose group was significantly higher than that of conventional group(P<0.05). Conclusion: The diagnostic value of low-dose spiral CT dynamic scanning for COPD is equivalent to that of conventional dose CT dynamic scanning, and can guarantee the image quality, which can significantly reduce the radiation dose, improve the satisfaction of COPD patients at the same time, which has certain clinical application value. [ABSTRACT FROM AUTHOR]

Copyright of Progress in Modern Biomedicine is the property of Publishing House of Progress in Modern Biomedicine and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The purpose of this study was to compare the scan time, image quality and radiation dose of CT urograms (CTU) using a split vs. single bolus contrast media injection technique. A total of 241 consecutive CTUs performed between August 2019-February 2020 were retrospectively reviewed. There were three study groups: Group 1, <50 years old, 50/80 cc split-bolus administered at 0 and 700 s post initiation of injection, with combined nephrographic and excretory phases; group 2, =50 years old, same split-bolus protocol; and group 3, ≥50 years old, 130 cc single bolus injection, with nephrographic and excretory phases acquired at 100 s and 460 s post injection initiation. The recorded data elements were scan time, number of excretory phases, imaging quality based on opacification of the urinary collecting system (<50%, 50-75%, 75-100%), and dose-length product (DLP). Associations between group and categorical variables were assessed (Chi-square); mean scan time and DLP were compared (one-way ANOVA). Following analysis, proportionally fewer CTUs required a repeat excretory phase in group 3 (32/112, 28.6%) than in groups 1 (25/48, 52.1%) and 2 (37/80, 46.3%) (p = 0.006). Mean scan time was significantly lower in group 3 (678 s) than in groups 1 (1046 s) and 2 (978 s) (p < 0.0001). There was no association between groups and image quality (p = 0.13). DLP was higher in group 3 (1422 ± 837 mGy·cm) than in groups 1 (1041 ± 531 mGy·cm) and 2 (1137 ± 646 mGy·cm) (p = 0.003). In conclusion, single bolus CTU resulted in significantly fewer repeat phases and faster scan time at the expense of a slightly higher radiation dose. [ABSTRACT FROM AUTHOR]

Imaging of multiple maritime moving targets is a challenging task in the synthetic aperture radar (SAR) system owing to the fact that the complex target motion produces evident image defocusing. Given that the sparsity of ship targets in the SAR image, the authors propose a new imaging method of multiple maritime moving targets based on sparsity Bayesian learning. To avoid the overcomplete velocity dictionary with heavy computational burden, the Gaussian chirplet transform is exploited and improved based on the velocity constraint to estimate target Doppler parameters for the observation matrix construction. An observation model is established for imaging multiple ship targets. In the proposed method, the multiple ship target imaging task is formulated into the sparsity Bayesian framework, which provides a posterior density function for the target image and improves the imaging quality over the conventional methods based on the point estimate. The Bayesian compressive sensing (BCS) using a hierarchical form of the Laplace prior is applied to reconstruct the moving target image. Since BCS provides an estimation of the uncertainty in the reconstruction, the sea clutter can be well suppressed while the multiple targets are refocused. Simulations and experimental Gaofen‐3 data are performed to verify the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

Rationale and Objectives: To prospectively compare the image quality (IQ) and lesion detection performance of reduced field-of-view (rFOV) and full FOV (fFOV) diffusion-weighted imaging (DWI) sequences in detecting insulinomas.Materials and Methods: From October 2017 to September 2018, 67 patients with suspected insulinomas were prospectively enrolled and underwent imaging with both types of DWI sequences. The slice thickness (4 mm) and slice gaps (1 mm) were the same for the two DWI sequences, and the TR/TE was 2235/56 ms for the rFOV sequence and 1892/63 ms for the fFOV sequence. Three radiologists independently assessed the imaging quality (IQ) subjectively with a 5-point scale and objectively with signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) measurements. The IQ scores, CNR, SNR, lesion detection rates, and ADC values were compared. Receiver operating characteristic curves were generated, and the area under the curve (AUC) was used to compare the diagnostic performance.Results: Fifty patients were tumor positive, with 65 tumors (size: 1.31 ± 0.77 cm, range: 0.6-5.8 cm). The IQ score, SNR, and CNR were significantly higher for rFOV DWI than for fFOV DWI (IQ: 3.64 ± 0.487 vs 3.310 ± 0.577, SNR: 22.520 ± 8.690 vs 10.284 ± 3.321, CNR: 3.454 ± 2.642 vs 1.327 ± 2.801, and all p < 0.05). For lesions less than 1.5 cm (n = 55), the lesion detection rates of the rFOV were statistically improved compared to those of the fFOV (90.7% vs. 75.9%, p = 0.039). The sensitivity of lesion detection was significantly improved with the rFOV-DWI sequences compared to that with the fFOV-DWI sequences (0.924 vs. 0.773, p = 0.013). The ADC values of the two DWI sequences were consistent for insulinomas and normal parenchyma.Conclusion: Considering the improvements in overall IQ and lesion detection and the consistency of ADC measurements, we suggest that rFOV DWI is a reliable auxiliary alternative to fFOV DWI for clinical practice in the detection of pancreatic insulinomas. [ABSTRACT FROM AUTHOR]

Background: To investigate the impact of scanning parameter in cone‐beam computed tomography (CBCT) images on accuracy and confidence with measurements of furcation involvement (FI) in maxillary molars. Material and methods: Six half cadaver heads with present maxillary molars (n = 10) were available. CBCT scans with the fixed‐parameter field of view (4 × 4 cm, 12 × 17 cm) amperage and voltage (4 mA, 90 kV) and with varying scan modes (SM), that is images/scan (IS), voxel sizes (VZ) and rotation (R), were performed using one CBCT apparatus. The images were analysed by two calibrated investigators. Horizontal FI's were measured in mm or a "through and through" destruction (FI degree III) was recorded. Each rater scored the FI measurements performed in each scan as "confident" or as "not confident". Data were statistically analysed using chi‐square tests. Results: The agreement between CBCT FI measurements and intra‐surgical FI measurements varied according to SM (SM HiSp 180°, 0.08: kappa 0.538, CI; 95%: 0.362–0.714; SM Std. 360°, 0.25: kappa 0.698, CI; 95%: 0.534–0.861). The number of measurements scored as "confident" varied according to SM (SM Std. 360°, 0.08:52 out of 60 measurements; SM Std. 360°, 0.25:16 out of 60 measurements; p <.001). Conclusions: SM of CBCT significantly affect the confidence with FI measurements in maxillary molars. [ABSTRACT FROM AUTHOR]

Copyright of Laser Technology is the property of Gai Kan Bian Wei Hui and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to reduce the influence of the optical window on the image quality of a hypersonic visible light optical remote sensor, we propose a method of adding a double-layer semicircular honeycomb core microstructure with flexible support of a high temperature elastic alloy between a window glass and a frame to reduce the influence of complex thermal stress on the surface accuracy of the optical window. An equivalent model of a semicircular honeycomb structure was established, the elastic parameters of the semicircular honeycomb sandwich microstructure were derived by an analytical method, and a numerical verification and finite element simulation were carried out. The results show that the equivalent model is in good agreement with the detailed model. The optical-mechanical-thermal integrated simulation analysis of the optical window assembly with flexible supporting microstructure proves that the semicircular honeycomb sandwich flexible supporting structure has a positive effect on stress attenuation of the window glass and ensures the wave aberration accuracy of the transmitted optical path difference of the optical window (PV < 0.665 λ, RMS < 0.156 λ, λ = 632.8 nm). Combined with the actual optical system, the optical performance of the window assembly under the flexible support structure is verified. The simulation results show that the spatial frequency of the modulation transfer function (MTF) of the optical system after focusing is not less than 0.58 in the range of 0–63 cycle/mm and the relative decline of MTF is not more than 0.01, which meet the imaging requirements of a remote sensor. The study results show that the proposed metal-based double-layer semicircular honeycomb sandwich flexible support microstructure ensures the imaging quality of the optical window under ultra-high temperature conditions.

In through-the-wall radar imaging, compressed sensing techniques have been applicable for small amount of observations to reconstruction walls or targets imaging in the scenes. The authors consider building walls imaging. The proposed approach exploits a low-rank and sparse model to extract the wall returns from radar signals, and then minimises the total variation regularisation problem for reconstructing building walls imaging using the sparsity of their spatial variations. The results of simulation exhibit that the proposed approach effectively enhances the imaging quality of building walls.

Target detection is an important part of synthetic aperture radar (SAR) image interpretation, and its performance directly affects the accuracy of localisation and target recognition results in the region of interest. However, the SAR system resolution largely determines the SAR image index and imaging quality, and the target detection performance is closely related to the SAR system resolution in addition to the detection method. To improve the detection performance, the correlation between system resolution and target detection is investigated in this study. Multiple SAR images are used to test a SAR system with reduced resolution obtained by multi-look processing. At the theoretical level, the effect of different resolutions on target detection performance is analysed. MSTAR images, containing image chips with centred targets of varying orientation, are used to analyse the accuracy of the results. By comparing the measured experimental data with the simulation results, it can be obtained that the detection performance is the best when the resolution is roughly equal to the target scale.

Due to high attitude and long synthetic aperture time of geosynchronous synthetic aperture radar (GEOSAR), working in the L band, ionosphere and troposphere severely impact the focusing performance of this radar. In this study, considering the movement characteristics of GEOSAR, the range error model caused by the atmospheric refractive index based on non ‘stop-and-go’ assumption is inferred. Then, the echo signals under the influence of ionosphere and troposphere are deduced, respectively. Finally, the influences of ionosphere and troposphere on GEOSAR focusing performance are analysed and simulated. The simulated results validate that troposphere and ionosphere are the important factors that affect the imaging quality. The tropospheric effects are relatively small. The influence of ionosphere on imaging performance along range and azimuth is much greater, often resulting in image drift and azimuth resolution decline. Change of ionospheric total electron content is more intense, they lower the imaging quality.

A novel method for synthetic aperture radar (SAR) three-dimensional (3D) sparse imaging based on a coprime linear array (CLA) is proposed. To reduce the geometric resolution loss caused by under-sampled sparse SAR, a jointed sparse imaging approach is used. In this scheme, the coprime sampled data of CLA is separately processed via the iterative reweight least-squares approach, and their recovered results are combined to cancel the false targets and grating-lobes to improve the imaging quality. Both simulated and experimented results demonstrate the effectiveness of the method. It shows that the exploiting of CLA and sparse recovery can significantly reduce the linear array antenna amount and the geometric resolution loss compared with the conventional uniform linear array SAR.

Target detection is an important part of synthetic aperture radar (SAR) image interpretation, and its performance directly affects the accuracy of localisation and target recognition results in the region of interest. However, the SAR system resolution largely determines the SAR image index and imaging quality, and the target detection performance is closely related to the SAR system resolution in addition to the detection method. To improve the detection performance, the correlation between system resolution and target detection is investigated in this study. Multiple SAR images are used to test a SAR system with reduced resolution obtained by multi-look processing. At the theoretical level, the effect of different resolutions on target detection performance is analysed. MSTAR images, containing image chips with centred targets of varying orientation, are used to analyse the accuracy of the results. By comparing the measured experimental data with the simulation results, it can be obtained that the detection performance is the best when the resolution is roughly equal to the target scale. [ABSTRACT FROM AUTHOR]

Due to high attitude and long synthetic aperture time of geosynchronous synthetic aperture radar (GEOSAR), working in the L band, ionosphere and troposphere severely impact the focusing performance of this radar. In this study, considering the movement characteristics of GEOSAR, the range error model caused by the atmospheric refractive index based on non 'stop-and-go' assumption is inferred. Then, the echo signals under the influence of ionosphere and troposphere are deduced, respectively. Finally, the influences of ionosphere and troposphere on GEOSAR focusing performance are analysed and simulated. The simulated results validate that troposphere and ionosphere are the important factors that affect the imaging quality. The tropospheric effects are relatively small. The influence of ionosphere on imaging performance along range and azimuth is much greater, often resulting in image drift and azimuth resolution decline. Change of ionospheric total electron content is more intense, they lower the imaging quality. [ABSTRACT FROM AUTHOR]

A novel method for synthetic aperture radar (SAR) three-dimensional (3D) sparse imaging based on a coprime linear array (CLA) is proposed. To reduce the geometric resolution loss caused by under-sampled sparse SAR, a jointed sparse imaging approach is used. In this scheme, the coprime sampled data of CLA is separately processed via the iterative reweight least-squares approach, and their recovered results are combined to cancel the false targets and grating-lobes to improve the imaging quality. Both simulated and experimented results demonstrate the effectiveness of the method. It shows that the exploiting of CLA and sparse recovery can significantly reduce the linear array antenna amount and the geometric resolution loss compared with the conventional uniform linear array SAR. [ABSTRACT FROM AUTHOR]

The lobster-eye optical system is widely used in the wide field of view (FOV) soft x-ray imaging device. The payload soft x-ray imager (SXI) onboard the solar wind magnetosphere ionosphere link explorer satellite will apply this technology to achieve panoramic imaging of the dayside magnetosphere. In order to optimize the imaging performance of SXI, we focus on geometric parameters optimization of a lobster-eye lens. The results show an appropriate microchannel ratio of length to width of lobster-eye optics with radius of curvature of 600 mm could be 30:1 (microchannel width of 40 μm and length of 1.2 mm). For a monochromatic parallel light source with energy of 1 keV, this combination of parameters can theoretically provide relatively large total effective area of about 15.52 cm² and focusing efficiency of about 0.2887 along with spatial angular resolution of about 6 arc min at the center of FOV. Combined with the actual lobster-eye optics, the aberrations from deformation of the microchannel, the deviation of radius of curvature and planar detector are analyzed. For SXI with planar CCD detector, an optimum focal length could be 304.2 mm to ensure better resolution in full FOV [ABSTRACT FROM AUTHOR]

Purpose: Guided waves generated from bone cortex inevitably act on microbubbles flowing through skeletal muscle capillaries in contrast‐enhanced ultrasound (CEUS) and might influence the image quality. However, the action mechanism underlying the guided waves influence is still unknown, especially under contrast pulse‐inversion transmission mode. This study aimed to clarify the influence of guided waves on pulse‐inversion CEUS, which was investigated via in vitro infusion experiments. Method: Tibia guided waves were detected at pulse‐inversion transmission and then characterized by using a short‐time Fourier transform energy distribution. Using results at normal incidence as a baseline, the influence of guided wave dispersion on the contrast and resolution of pulse‐inversion CEUS was investigated at an oblique incidence through continuous microbubbles infusion experiments in a vessel–tibia flow phantom. Results: Frequency‐dispersive property of tibia guided waves was observed at phases 0° and 180°, which improved the contrast of CEUS and reduced its resolution. Pulse‐inversion CEUS balanced the contrast enhancement and resolution degeneration induced by guided waves. By contrast, contrast‐to‐tissue ratio of pulse‐inversion CEUS increased by up to 109.1 ± 13.2% (P < 0.05) due to guided waves and its resolution was up to 0.9 ± 0.1 times that of baseline. Conclusions: Alterations of contrast and resolution in pulse‐inversion CEUS induced by guided waves might provide an additional assessment for the capillary perfusion in the skeletal muscle near the bone cortex. [ABSTRACT FROM AUTHOR]

Objective: To explore the application value of gemstone energy spectrum CT for evaluating the quality of coronary stent imaging. Methods: The imaging data of 56 patients after coronary artery stent implantation were retrospectively analyzed. The study group was divided into four groups according to the thickness and diameter of the stent. By analyzing the imaging quality of coronary artery with gemstone energy spectrumCT and comparing with coronary angiography, the value of gemstone energy spectrumCT in evaluating the quality of in-stent imaging after percutaneous coronary intervention. Results: The sensitivity, specificity and negative predictive value of in-stent restenosis of gemstone energy spectrum CT were 100 %, 98.6 %and 100 %, respectively. IQ score for stent diameter ≥ 3 mm was significantly higher than that for stent diameter <3 mm for stents with both thick struts and thin struts. However, there is no difference in the evaluation rate of in-stent imaging quality between the diameter and thickness of the stent. Conclusions: Gemstone energy spectrumCT can provide excellent in-stent imaging quality. Gemstone energy spectrum CT can be used to evaluate in-stent imaging after coronary stenting instead of coronary angiography. [ABSTRACT FROM AUTHOR]

Ultrasound plane wave imaging technology has been applied to more clinical situations than ever before because of its rapid imaging speed and stable imaging quality. Most transducers used in plane wave imaging are linear arrays, but their structures limit the application of plane wave imaging technology in some special clinical situations, especially in the endoscopic environment. In the endoscopic environment, the size of the linear array transducer is strictly miniaturized, and the imaging range is also limited to the near field. Meanwhile, the near field of a micro linear array has serious mutual interferences between elements, which is against the imaging quality of near field. Therefore, we propose a new structure of a micro ultrasound linear array for plane wave imaging. In this paper, a theoretical comparison is given through sound field and imaging simulations. On the basis of primary work and laboratory technology, micro uniform and non-uniform linear arrays were made and experimented with the phantom setting. We selected appropriate evaluation parameters to verify the imaging results. Finally, we concluded that the micro non-uniform linear array eliminated the artifacts better than the micro uniform linear array without the additional use of signal processing methods, especially for target points in the near-field. We believe this study provides a possible solution for plane wave imaging in cramped environments like endoscopy.