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The velocity of blood in vessels is an important indicator that reflects the microcirculatory status. The core of the measurement technology, which is based on spatiotemporal (ST) image, is to map the cell motion trace to the two-dimensional ST image, and transfer the measurement of flow velocity to the detection of trace orientation in ST image. This paper proposes a trace orientation measurement algorithm is based on Randomized Hough Transformation and projection transformation, and it is able to estimate trace orientation and flow velocity in noisy ST images. Experiments showed that the agreement between the results by manual and by the proposed algorithm reached over 90%.
Subject(s)
Humans , Algorithms , Blood Flow Velocity , Microcirculation , Spatio-Temporal AnalysisABSTRACT
<p><b>OBJECTIVE</b>The assessment result of microcirculatory perfusion provides significant evidence for the detection of microcirculatory alterations in sepsis patients, and functional capillary density based on vessel segmentation can reflect microcirculatory perfusion effectively.</p><p><b>METHODS</b>First, preprocessing comprise operations to improve the quality of images in order to maximize the contrast between background and vessels. Secondly, adaptive local thresholding is used for initial segmentation to get the general vessel region. Finally, post-processing technique reduces the image artifacts and links the vessel fragment, and then functional capillary density is calculated based on the segmentation results.</p><p><b>RESULTS</b>Several sublingual microcirculatory data have been tested, and the agreement between the results by AVA and the proposed algorithm reached up to 92%.</p><p><b>CONCLUSIONS</b>The method can realize automated assessment of sublingual microcirculatory perfusion rapidly and accurately, and has strong clinical value.</p>
Subject(s)
Algorithms , Image Processing, Computer-Assisted , Methods , Microcirculation , Mouth FloorABSTRACT
Objective:This paper studied the electromagnetic-driven pressure control system in the automatic measurement of intraocular pressure (IOP).The accuracy of pressure control directly impacts on the accuracy of IOP measurements,so it calls for precise pressure to achieve closed-loop control.Methods:According to the actual needs of IOP measuring,we got the structural and electromagnetic parameters of the electromagnetic drive system by combining the methods of numerical calculation and ANSYS simulation.Using the FC bus and digital-analog conversion,the microcontroller module controlled the drive current digitally and precisely in order to achieve closed-loop control of pressure.Results:The experimental results showed that in the electromagnetic pressure control system,the pressure range was 0 N～0.48982 N,the accuracy 0.00058 N,the drive current control error about 1% on average.Besides,the electromagnetic force and the excitation current showed a good linear relationship in the same stroke.Conclusions:The electromagnetic pressure control system achieved a good result in closed-loop control of pressure.The control pressure range and control accuracy were in line with the standard of Goldmann applanation tonometer.According to the results,this study laid the foundation for the further development of IOP automatically measuring instruments.
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Objective To develop a system for detection and diagnosis of osteoporosis by using quantitative ultrasound technology.Methods An ARM embedded system was used to measure the speed of ultrasound,the broadband ultrasound attenuation(BUA) and the stiffness.The speed of ultrasound mainly reflects bone structural features,BUA mainly reflects bone density,and stiffness can synthetically reflects bone intensity.Results Based on an ARM microprocessor,the whole system could diagnose osteoporosis through the parameters sent by ultrasound.Conclusion The system for ultrasonic diagnosis of osteoporosis based on ARM can achieve precise diagnosis in clinic by setting osseous parameters database of normal people in different age,weight and sex.
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Objective To fit the functional relation between Percentage Depth Dose and depth by Newton Interpolation. Methods After analyzing the data of Percentage Depth Dose from different manufacturers' linear accelerators, the average of Percentage Depth Dose with same depth was calculated, and then the average data was determined. The interval was set and the interpolation node was selected for simulating the cubic polynomial with PDD and depth. Results Comparing the calculated values by the function with the measured ones, the error was less than 1%. Conclusion The function simulated with Newton Interpolation is applicable in routine clinical radiotherapy and research.
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The advantages of LabVIEW are becoming more and more distinct in instruments design.The ECG signals from MIT database are introduced using LabVIEW on software platform.They are treated with band stop,high pass,low pass filters in turn,and then heart rate is analyzed and calculated.Finally the amplitude and duration of QRS are recognized.
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In view of China's medical equipment industry has not been equipped with a sound system and strict administration, it is wise to draw on FDA recommendations and seek effective ways of solving EMI problems. Further should focus on improving the performance of medical equipment so as to adapt to the different environment. In the end, the design of healthcare facilities to meet EMC standards is put forward specifically in four parts of electronic circuits, power circuits, display device, and the mechanical shell.