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Dynamic Optical Coherence Tomography Is a New Technique for Imaging Skin Around Lower Extremity Wounds
摘要： Chronic wounds such as venous leg ulcers invariably heal slowly and recur. In the case of venous leg ulcers, poor healing of chronic wounds is variously attributed to ambulatory hypertension, impaired perfusion and diffusion, presence of chronic inflammation at wound sites, lipodermatosclerosis, and senescence. The aim of this study was to investigate whether a new technique, optical coherence tomography (OCT), which permits imaging of blood capillaries in the peri-wound skin, can provide new insights into the pathology. OCT and its recent variant, dynamic OCT, permit rapid noninvasive depth-resolved imaging of the capillaries in the superficial dermis via a handheld probe, showing the morphology and density of vessels down to 20 μm in diameter. We used dynamic OCT to investigate 15 chronic wounds and assess characteristics of the vessels at the 4 poles around the wounds, the wound bed, adjacent dermatosclerosis, and unaffected skin. The results of the study show that both vessel morphology and density in the wound edges are dramatically different from that in healthy skin, showing clusters of glomuleri-like vessels (knot-like forms or clumps) and an absence of linear branching vessels, and also greater blood perfusion. Such vessel shapes are reported to be associated with tissue growth. The OCT imaging procedure was rapid and well tolerated by patients and provided new information not available from other devices. Thus, OCT appears to have great promise as a tool for the evaluation and study of chronic ulcers.
关键词： capillary imaging,venous leg ulcer,chronic wounds,optical coherence tomography
更新于2025-09-23 15:22:29
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Eggshell apex abnormalities caused by two different Mycoplasma synoviae genotypes and evaluation of eggshell anomalies by full-field optical coherence tomography
摘要： Background: Mycoplasma synoviae (MS) is an important poultry pathogen worldwide. This bacterium may cause eggshell changes including an altered shell surface, thinning, and increased translucency in different areas, which leads to a greater incidence of eggshell cracks and breaks. In the present study the association between experimental infection of birds with two field strains of MS from different genotypes and the production of abnormal eggs is described. The analysis of those eggshells using a full-field optical coherence tomography (FF OCT) scanner is also reported. Results: Eggshell samples were obtained from three experimental groups of chickens: one control and two infected tracheally with field strains of MS which produced abnormal eggs. In both experimental groups infected with MS a reduction of mean daily egg production by 11% was observed compared to the control group, which started at 21 to 42 dpi. Eggshell apex abnormalities increased to 24.5% of eggs and in some cases, soft-shelled eggs were produced. This study provides the first analysis of shells from anomalous eggs carried out using FF OCT, which allows three-dimensional structural imaging of an investigated sample at micrometre scale. FF OCT showed ultrastructural changes in eggshells and a smaller number of pores on the entire surface of the affected shells. Conclusions: The eggshell pathology and the concomitant egg production losses that result from infections highlight the economic significance of MS in commercial poultry. There are differences in the strains of MS which may induce eggshell apex abnormalities (EAA) and egg production losses. The use of FF OCT, which is a noninvasive measurement method based on analysis of the light backscattered from the measured object, will confer the ability to control the quality of eggshells in flocks infected with MS.
关键词： Poultry,Apex eggshell abnormalities,EAA,Mycoplasma synoviae,Full-field optical coherence tomography
更新于2025-09-23 15:22:29
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Common venous renal trunk in two dogs: Multidetector computed tomographic imaging findings
摘要： In dogs, variation in the branching pattern of renal veins is rare with only few patterns reported. This report describes two unusual anomalies of the renal vein branching patterns in two dogs. In dog 1, a common renal trunk drained both kidneys, in a T-shape pattern, in the caudal vena cava after a long right perirenal course. In dog 2, a common venous trunk branched cranially from the pre-renal segment of an azygos-caudal vena cava venous trunk and divided into the renal veins in a Y-shape pattern. Proper knowledge of the possible anatomical variations in renal venous drainage may be helpful during imaging assessment and surgical planning of several canine diseases involving the abdominal vasculature and retroperitoneal space.
关键词： renal veins,caudal vena cava,gonadal veins,dog,computed tomography,angiography
更新于2025-09-23 15:22:29
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Performance of Landweber iteration algorithm in tomographic image reconstruction
摘要： The rapid growth of computed tomography has been accompanied by equally advancing in image reconstruction algorithm also. The fundamental inverse problem is the reconstruction of a function from finitely many measurements, so pertaining to that function. The measured data are limited, and it cannot serve to determine one single correct solution. The iterative reconstruction image reconstruction algorithms have stable solution to the limited projection. In this paper, Landweber-based iteration image reconstruction is simulated and its performance is compared with different algorithm. Then, the quality of the reconstructed image is expressed in terms of mean absolute error and correlation coefficient as compared to the original image. The entire simulations are performed in Matlab tool.
关键词： image reconstruction,computed,Landweber algorithm,tomography,limited projection,iterative reconstruction
更新于2025-09-23 15:22:29
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Plaque characteristics and slow flow during percutaneous coronary intervention of irregular protrusion by optical coherence tomography
摘要： Irregular protrusion on optical coherence tomography (OCT) is associated with clinical events and target lesion revascularization. We investigated clinical and procedure characteristics, plaque characteristics, slow flow after stent implantation, and clinical outcomes with irregular protrusion using OCT. Eighty-four lesions in 76 patients undergoing OCT before percutaneous coronary intervention were evaluated. Irregular protrusion was defined as protrusion of material with an irregular surface into the lumen between stent struts with a maximum height of ≥100 μm. Lesions with irregular protrusion were found in 56% (47/84). Compared with lesions without irregular protrusion, those with irregular protrusion had significantly higher low-density lipoprotein cholesterol (LDL-C) levels (108 ± 31 mg/dl vs. 95 ± 25 mg/dl, P = 0.044); a tendency toward decreased use of statins [44% (19/43) vs. 67% (22/33), P = 0.065]; significantly larger reference vessel diameter (3.12 ± 0.53 mm vs. 2.74 ± 0.63 mm, P = 0.004); more frequent slow flow after stent implantation [38% (18/47) vs. 11% (4/37), P = 0.006]; higher incidence of thin-cap fibroatheromas [TCFAs; 49% (23/47) vs. 5% (2/37), P < 0.001]; plaque rupture [40% (19/47) vs. 16% (6/37), P = 0.018]; and a tendency higher incidence of 1-year adverse clinical outcomes (death, acute myocardial infarction, acute coronary syndrome, or target lesion revascularization) [12% (5/43) vs. 0% (0/33), P = 0.075]. In conclusion, irregular protrusion on OCT was associated with high plaque vulnerability, higher LDL-C, less frequent use of statin, larger vessel diameter, slow flow after stent implantation, and 1-year adverse clinical outcomes.
关键词： Slow flow,Optical coherence tomography,Irregular protrusion
更新于2025-09-23 15:22:29
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Treating cerebrovascular diseases in hybrid operating room equipped with a robotic angiographic fluoroscopy system: level of necessity and 5-year experiences
摘要： Background A hybrid operating room (OR) equipped with robotic angiographic fluoroscopy system has become prevalent in neurosurgery. The level of necessity of the hybrid OR in treating cerebrovascular diseases (CVD) is rarely discussed. Objective The authors proposed a scoring and classification system to evaluate the cerebrovascular procedures according to the level of treatment necessity for CVD in a hybrid OR and shared our 5-year experiences. Methods From December 2009 to January 2016, the registry of cerebrovascular procedures performed in the hybrid OR was retrieved. A scoring system was used to evaluate the importance of the surgical and interventional components of a cerebrovascular procedure performed in the hybrid OR. The score of either component ranged from 1, 1.5, to 2 (1 = no role, 1.5 = supplementary or informative, 2 = important or therapeutic). The total score of a procedure was by multiplying two individual scores. Levels of necessity were classified into level A (important), level B (beneficial), and level C (replaceable). Results A total of 1027 cerebrovascular procedures were performed during this period: diagnostic angiography in 328, carotid artery stenting in 286, aneurysm coiling in 128, intra-operative DSA in 101, aspiration of ICH under image guidance in 79, intra-arterial thrombolysis/thrombectomy in 51, intracranial angioplasty/stenting in 30, hybrid surgery/serial procedures in 19, and rescue surgery during embolization in 5. According to the scoring system, hybrid surgery and serial procedures scored the highest points (2 × 2). The percentages distributed at each level: levels A (2.3%), B (17.5%), and C (80.2%). Conclusion This study conveys a concept of what a hybrid OR equipped with robotic angiographic fluoroscopy system is capable of and its potential. For cerebrovascular diseases, hybrid OR exerts its value via hybrid surgery or avoiding patient transportation in serial procedures (level A), via providing real-time high-quality angiography and image guidance (level B), which constituted about 20% of the cases. The subspecialty of the group using the hybrid OR directly reflects on the number of procedures categorized in each level. In a hybrid OR, innovative treatment strategies for difficult-to-treat CVD can be developed.
关键词： Cone-beam computed tomography,Endovascular,Hybrid surgery,Robotic angiographic fluoroscopy system,Cerebrovascular disease,Hybrid operating room,Digital subtraction angiography
更新于2025-09-23 15:22:29
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Terahertz Differential Computed Tomography: a Relevant Nondestructive Inspection Application
摘要： In recent years, tremendous advances have been made in the choice of materials used in the industry. With weight reduction as the goal, composite and polymer materials are more and more popular but they are almost transparent to X-ray. Because of this, interest has grown in other wavelengths like terahertz (THz). Due to a difference in how X-ray and THz propagate, X-ray CT algorithms cannot be directly used. For example, THz induces refraction making the reconstruction problem nonlinear. In this paper, we present a new algorithm which complies with beam profile intensities, refraction, and reflection. It is based on linearizing the reconstruction process around a computer-aided design (CAD) model of the object to be reconstructed. The method we propose computes the deviation between the object and this model.
关键词： Terahertz computed tomography,Inverse problem,Nondestructive testing,Modeling,Monte Carlo,Refraction,Nonlinear problem,Projection simulation
更新于2025-09-23 15:22:29
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Case Study of Empirical Beam Hardening Correction Methods for Dimensional X-ray Computed Tomography Using a Dedicated Multi-material Reference Standard
摘要： This paper presents a case study of two selected beam hardening correction methods and their effects on dimensional measurements of multi-material objects. The methods under test are empirical cupping correction (ECC) and empirical dual energy calibration (EDEC). These methods were originally developed for medical applications and their potential for the reduction of artefacts is typically only analysed based on grey value images. For testing and benchmarking of the mentioned methods for dimensional metrology, a dedicated multi-material reference standard—a multi-material hole cube—is used. This reference standard was originally developed for acceptance testing of CT systems. This paper shows a second application of this standard. The reference standard has been calibrated by tactile measurements to assess centre–centre distance errors as well as patch-based bidirectional length measurement errors on beam hardening corrected data and on uncorrected data. For the application of the method also to industrial multi-material scenarios, slight modifications of the ECC method are proposed. Practical aspects of both the ECC and the EDEC approaches as well as measurement results are analysed and discussed in detail. ECC was able to significantly improve dimensional measurements and was especially able to reduce extreme errors occurring in particular in multi-material scenarios by a factor of more than 4. EDEC, the dual-energy approach, reduced grey value inhomogeneities caused by artefacts even more. Its performance for dimensional measurements was however a little worse than ECC. EDEC data resulted in a slightly larger total range of residual measurement errors, mainly due to an elevated noise level.
关键词： Beam hardening correction,Industrial computed tomography,Multi-material measurements,Material influence,Dimensional metrology
更新于2025-09-23 15:22:29
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Quantum gate identification: Error analysis, numerical results and optical experiment
摘要： The identification of an unknown quantum gate is a significant issue in quantum technology. In this paper, we propose a quantum gate identification method within the framework of quantum process tomography. In this method, a series of pure states are applied to the gate and then a fast state tomography on the output states is performed and the data are used to reconstruct the quantum gate. The algorithm has computational complexity O(d3) with the system dimension d. The identification approach is compared with the maximum likelihood estimation method for the running time, which shows an efficiency advantage of our method. An error upper bound is established for the identification algorithm and the robustness of the algorithm against impurities in the input states is also tested. We perform a quantum optical experiment on a single-qubit Hadamard gate to verify the effectiveness of the identification algorithm.
关键词： Quantum system,Quantum tomography,Quantum gate identification,Computational complexity
更新于2025-09-23 15:22:29
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Macrophage uptake switches on OCT contrast of superparamagnetic nanoparticles for imaging of atherosclerotic plaques
摘要： Background: Optical coherence tomography (OCT) is an intravascular, high-resolution imaging technique that is used to characterize atherosclerotic plaques. However, the identification of macrophages as important markers of inflammation and plaque vulnerability remains difficult. Here, we investigate whether the uptake of very small iron oxide particles (VSOP) in macrophages, that cluster in phagolysosomes and allow high-quality magnetic resonance imaging (MRI) of atherosclerotic plaques, and uptake of ferumoxytol nanoparticles enhance detection of macrophages by OCT. Materials and methods: RAW 264.7 macrophage cells were incubated with VSOP (1 and 2 mM Fe) that have been clinically tested and ferumoxytol (8.9 mM Fe) that is approved for iron deficiency treatment and currently investigated as an MRI contrast agent. The light scattering of control macrophages, nanoparticle-labeled macrophages (2,000,000 in 500 μL) and nanoparticle suspensions was measured in synchronous wavelength scan mode using a fluorescence spectrophotometer. For OCT analyses, pellets of 8,000,000 non-labeled, VSOP-labeled and ferumoxytol-labeled RAW 264.7 macrophages were imaged and analyzed on an OPTIS? OCT imaging system. Results: Incubation with 1 and 2 mM VSOP resulted in uptake of 7.1±1.5 and 12±1.5 pg Fe per cell, which increased the backscattering of the macrophages in spectrophotometry 2.5- and 3.6-fold, whereas incubation with 8.9 mM Fe ferumoxytol resulted in uptake of 6.6±2 pg Fe per cell, which increased the backscattering 1.5-fold at 700 nm. In contrast, backscattering of non-clustered nanoparticles in suspension was negligible. Accordingly, OCT imaging could visualize significantly increased backscattering and signal attenuation of nanoparticle-labeled macrophages in comparison with controls. Conclusion: We conclude that VSOP and, to a lesser extent, ferumoxytol increase light scattering and attenuation when taken up by macrophages and can serve as a multimodal imaging probe for MRI and OCT to improve macrophage detection in atherosclerotic plaques by OCT in the future.
关键词： intravascular,magnetic resonance imaging,multimodal imaging,optical coherence tomography,vulnerability,inflammation
更新于2025-09-23 15:22:29