7,480 research outputs found

    Segmentation of ultrasound images of thyroid nodule for assisting fine needle aspiration cytology

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    The incidence of thyroid nodule is very high and generally increases with the age. Thyroid nodule may presage the emergence of thyroid cancer. The thyroid nodule can be completely cured if detected early. Fine needle aspiration cytology is a recognized early diagnosis method of thyroid nodule. There are still some limitations in the fine needle aspiration cytology, and the ultrasound diagnosis of thyroid nodule has become the first choice for auxiliary examination of thyroid nodular disease. If we could combine medical imaging technology and fine needle aspiration cytology, the diagnostic rate of thyroid nodule would be improved significantly. The properties of ultrasound will degrade the image quality, which makes it difficult to recognize the edges for physicians. Image segmentation technique based on graph theory has become a research hotspot at present. Normalized cut (Ncut) is a representative one, which is suitable for segmentation of feature parts of medical image. However, how to solve the normalized cut has become a problem, which needs large memory capacity and heavy calculation of weight matrix. It always generates over segmentation or less segmentation which leads to inaccurate in the segmentation. The speckle noise in B ultrasound image of thyroid tumor makes the quality of the image deteriorate. In the light of this characteristic, we combine the anisotropic diffusion model with the normalized cut in this paper. After the enhancement of anisotropic diffusion model, it removes the noise in the B ultrasound image while preserves the important edges and local details. This reduces the amount of computation in constructing the weight matrix of the improved normalized cut and improves the accuracy of the final segmentation results. The feasibility of the method is proved by the experimental results.Comment: 15pages,13figure

    Correlation between the peripapillary retinal nerve fiber layer thickness,structure changes in non-proliferative diabetic retinopathy and the changes of visual function

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    AIM:To study the correlation between and the peripapillary retinal nerve fiber layer(RNFL)thickness,structure changes in non-proliferative diabetic retinopathy(NPDR)and the the changes of visual function <p>METHODS:Eighty cases(80 eyes)of patients with NPDR who were in our hospital from January 2011 to December 2013 as group NPDR, 60 cases of patients(60 eyes)without retinopathy who were in the hospital were selected as non-diabetic retinopathy group(NRD)group, meanwhile, 50 healthy people who had health examination in our hospital as control group. The RNFL thickness and visual electrophysiological testing were performed on the study objects in the three groups, and the results were compared among groups.<p>RESULTS: Group NPDR's above, below, nasal, temporal and average RNFL thickness were 91.52±18.52, 88.63±21.65, 63.62±11.72, 60.42±9.13, 69.36±12.52μm,those of group NPDR were 111.32±21.90, 113.57±22.67, 74.31±11.74, 67.64±12.34, and 97.31±11.43μm,those of group control were 121.65±21.42, 129.32±23.31, 82.42±9.28, 80.32±8.51, 102.54±21.82μm. To compare of average thickness of RNFL of three groups, groups NPDR and NPD were thinner than that of control group; To compare each quadrant phase, above, below, nasal, the RNFL thickness among three groups had statistical significance(<i>P</i><0.05), while nasal sides had no obviously changes(<i>P</i>>0.05); At the same time, 60'P100 latency(MS), 60'P100 amplitude(V), 15'P100 latency(MS)and 15'P100 amplitude(V)of three groups had statistical significance(<i>P</i><0.05). <p>CONCLUSION: The changes of RNFL thickness have occurred in the early time of NPDR, and mainly the above, below and temporal, and it has a significant relevance with the changes of visual function
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