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Is it a normal phenomenon for pediatric patients to have brain leptomeningeal contrast enhancement on 3-tesla magnetic resonance imaging?
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作者 Min Ai Hang-Hang Zhang +1 位作者 Yi Guo Jun-Bang Feng 《World Journal of Radiology》 2024年第5期136-138,共3页
Determining whether sevoflurane sedation in children leads to“pseudo”prominent leptomeningeal contrast enhancement(pLMCE)on 3 Tesla magnetic resonance imaging will help reduce overdiagnosis by radiologists and clari... Determining whether sevoflurane sedation in children leads to“pseudo”prominent leptomeningeal contrast enhancement(pLMCE)on 3 Tesla magnetic resonance imaging will help reduce overdiagnosis by radiologists and clarify the pathophysiological changes of pLMCE. 展开更多
关键词 Pediatrics patients SEVOFLURANE BRAIN Prominent leptomeningeal contrast enhancement Magnetic resonance imaging
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Research on Wavelet-Based Algorithm for Image Contrast Enhancement 被引量:2
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作者 WuYing-qian DuPei-jun ShiPeng-fei 《Wuhan University Journal of Natural Sciences》 EI CAS 2004年第1期46-50,共5页
A novel wavelet-based algorithm for image enhancement is proposed in the paper. On the basis of multiscale analysis, the proposed algorithm solves efficiently the problem of noise over-enhancement, which commonly occu... A novel wavelet-based algorithm for image enhancement is proposed in the paper. On the basis of multiscale analysis, the proposed algorithm solves efficiently the problem of noise over-enhancement, which commonly occurs in the traditional methods for contrast enhancement. The decomposed coefficients at same scales are processed by a nonlinear method, and the coefficients at different scales are enhanced in different degree. During the procedure, the method takes full advantage of the properties of Human visual system so as to achieve better performance. The simulations demonstrate that these characters of the proposed approach enable it to fully enhance the content in images, to efficiently alleviate the enhancement of noise and to achieve much better enhancement effect than the traditional approaches. Key words wavelet transform - image contrast enhancement - multiscale analysis CLC number TP 391 Foundation item: Supported by the National Natural Science Foundation of China (69931010)Biography: Wu Ying-qian (1974-), male, Ph. D, research direction: image processing, image compression and wavelet. 展开更多
关键词 wavelet transform image contrast enhancement multiscale analysis
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A New Method of CT Medical Images Contrast Enhancement 被引量:1
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作者 SUNFeng-rong LIUWei WANGChang-yu MEILiang-mo 《Chinese Journal of Biomedical Engineering(English Edition)》 2004年第1期28-38,共11页
A new method of contrast enhancement is proposed in the paper using multiscale edge representation of images, and is applied to the field of CT medical image processing. Comparing to the traditional Window technique, ... A new method of contrast enhancement is proposed in the paper using multiscale edge representation of images, and is applied to the field of CT medical image processing. Comparing to the traditional Window technique, our method is adaptive and meets the demand of radiology clinics more better. The clinical experiment results show the practicality and the potential applied value of our method in the field of CT medical images contrast enhancement. 展开更多
关键词 contrast enhancement Dyadic wavelet transform Multiscale edge representation Computed tomography
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A General Framework of Reversible Data Hiding with Controlled Contrast Enhancement
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作者 Shaowei Weng Yiyun Liu +3 位作者 Yunqing Shi Bo Ou Chunyu Zhang Cuiping Wang 《Computers, Materials & Continua》 SCIE EI 2020年第1期157-177,共21页
This paper proposes a two-step general framework for reversible data hiding(RDH)schemes with controllable contrast enhancement.The first step aims at preserving visual perception as much as possible on the basis of ac... This paper proposes a two-step general framework for reversible data hiding(RDH)schemes with controllable contrast enhancement.The first step aims at preserving visual perception as much as possible on the basis of achieving high embedding capacity(EC),while the second step is used for increasing image contrast.In the second step,some peak-pairs are utilized so that the histogram of pixel values is modified to perform histogram equalization(HE),which would lead to the image contrast enhancement.However,for HE,the utilization of some peak-pairs easily leads to over-enhanced image contrast when a large number of bits are embedded.Therefore,in our proposed framework,contrast over-enhancement is avoided by controlling the degree of contrast enhancement.Since the second step can only provide a small amount of data due to controlled contrast enhancement,the first one helps to achieve a large amount of data without degrading visual quality.Any RDH method which can achieve high EC while preserve good visual quality,can be selected for the first step.In fact,Gao et al.’s method is a special case of our proposed framework.In addition,two simple and commonly-used RDH methods are also introduced to further demonstrate the generalization of our framework. 展开更多
关键词 Reversible data hiding controlled contrast enhancement general framework PEE-based RDH method IT-based RDH method
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CNN-Based Forensic Method on Contrast Enhancement with JPEG Post-Processing
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作者 Ziqing Yan Pengpeng Yang +2 位作者 Rongrong Ni Yao Zhao Hairong Qi 《Computers, Materials & Continua》 SCIE EI 2021年第12期3205-3216,共12页
As one of the most popular digital image manipulations,contrast enhancement(CE)is frequently applied to improve the visual quality of the forged images and conceal traces of forgery,therefore it can provide evidence o... As one of the most popular digital image manipulations,contrast enhancement(CE)is frequently applied to improve the visual quality of the forged images and conceal traces of forgery,therefore it can provide evidence of tampering when verifying the authenticity of digital images.Contrast enhancement forensics techniques have always drawn significant attention for image forensics community,although most approaches have obtained effective detection results,existing CE forensic methods exhibit poor performance when detecting enhanced images stored in the JPEG format.The detection of forgery on contrast adjustments in the presence of JPEG post processing is still a challenging task.In this paper,we propose a new CE forensic method based on convolutional neural network(CNN),which is robust to JPEG compression.The proposed network relies on a Xception-based CNN with two preprocessing strategies.Firstly,unlike the conventional CNNs which accepts the original image as its input,we feed the CNN with the gray-level co-occurrence matrix(GLCM)of image which contains CE fingerprints,then the constrained convolutional layer is used to extract high-frequency details in GLCMs under JPEG compression,finally the output of the constrained convolutional layer becomes the input of Xception to extract multiple features for further classification.Experimental results show that the proposed detector achieves the best performance for CE forensics under JPEG post-processing compared with the existing methods. 展开更多
关键词 contrast enhancement forensics convolutional neural networks robust forensics JPEG compression
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Contrast Enhancement Using Weighted Coupled Histogram Equalization with Laplace Transform
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作者 Huimin Hao Wenbin Xin +4 位作者 Minglong Bu He Wang Yuan Lan Xiaoyan Xiong Jiahai Huang 《Journal of Harbin Institute of Technology(New Series)》 CAS 2022年第4期32-40,共9页
Histogram equalization is a traditional algorithm improving the image contrast,but it comes at the cost of mean brightness shift and details loss.In order to solve these problems,a novel approach to processing foregro... Histogram equalization is a traditional algorithm improving the image contrast,but it comes at the cost of mean brightness shift and details loss.In order to solve these problems,a novel approach to processing foreground pixels and background pixels independently is proposed and investigated.Since details are mainly contained in the foreground,the weighted coupling of histogram equalization and Laplace transform were adopted to balance contrast enhancement and details preservation.The weighting factors of image foreground and background were determined by the amount of their respective information.The proposed method was conducted to images acquired from CVG⁃UGR and US⁃SIPI image databases and then compared with other methods such as clipping histogram spikes,histogram addition,and non⁃linear transformation to verify its validity.Results show that the proposed algorithm can effectively enhance the contrast without introducing distortions,and preserve the mean brightness and details well at the same time. 展开更多
关键词 contrast enhancement weighted processing histogram equalization Laplace transform
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Derivation of Optimal Global Equalization Function with Variable Size Block Based Local Contrast Enhancement
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作者 Ralph Oyini Mbouna Young-joon HAN 《Journal of Measurement Science and Instrumentation》 CAS 2010年第4期334-337,共4页
A conventional global contrast enhancement is difficult to apply in various images because image quality and contrast enhancement are dependent on image characteristics largely. And a local contrast enhancement not on... A conventional global contrast enhancement is difficult to apply in various images because image quality and contrast enhancement are dependent on image characteristics largely. And a local contrast enhancement not only causes a washed-out effect, but also blocks. To solve these drawbacks, this paper derives an optimal global equalization function with variable size block based local contrast enhancement. The optimal equalization function makes it possible to get a good quality image through the global contrast enhancement. The variable size block segmentation is firstly exeoated using intensity differences as a measure of similarity. In the second step, the optimal global equalization function is obtained from the enhanced contrast image having variable size blocks. Conformed experiments have showed that the proposed algorithm produces a visually comfortable result image. 展开更多
关键词 global oontrast enhancement local contrast enhancement optimal equalization function block segmentation variable size block
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A Bi-Histogram Shifting Contrast Enhancement for Color Images
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作者 Lord Amoah Ampofo Twumasi Kwabena 《Journal of Quantum Computing》 2021年第2期65-77,共13页
Recent contrast enhancement(CE)methods,with a few exceptions,predominantly focus on enhancing gray-scale images.This paper proposes a bi-histogram shifting contrast enhancement for color images based on the RGB(red,gr... Recent contrast enhancement(CE)methods,with a few exceptions,predominantly focus on enhancing gray-scale images.This paper proposes a bi-histogram shifting contrast enhancement for color images based on the RGB(red,green,and blue)color model.The proposed method selects the two highest bins and two lowest bins from the image histogram,performs an equalized number of bidirectional histogram shifting repetitions on each RGB channel while embedding secret data into marked images.The proposed method simultaneously performs both right histogram shifting(RHS)and left histogram shifting(LHS)in each histogram shifting repetition to embed and split the highest bins while combining the lowest bins with their neighbors to achieve histogram equalization(HE).The least maximum number of histograms shifting repetitions among the three RGB channels is used as the default number of histograms shifting repetitions performed to enhance original images.Compared to an existing contrast enhancement method for color images and evaluated with PSNR,SSIM,RCE,and RMBE quality assessment metrics,the experimental results show that the proposed method's enhanced images are visually and qualitatively superior with a more evenly distributed histogram.The proposed method achieves higher embedding capacities and embedding rates in all images,with an average increase in embedding capacity of 52.1%. 展开更多
关键词 contrast enhancement bi-histogram shifting histogram equalization
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Reversible Data Hiding with Contrast Enhancement Using Bi-histogram Shifting and Image Adjustment for Color Images
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作者 Goma Tshivetta Christian Fersein Jorvialom Lord Amoah 《Journal of Quantum Computing》 2022年第3期183-197,共15页
Prior versions of reversible data hiding with contrast enhancement(RDHCE)algorithms strongly focused on enhancing the contrast of grayscale images.However,RDHCE has recently witnessed a rise in contrast enhance-ment a... Prior versions of reversible data hiding with contrast enhancement(RDHCE)algorithms strongly focused on enhancing the contrast of grayscale images.However,RDHCE has recently witnessed a rise in contrast enhance-ment algorithms concentrating on color images.This paper implies a method for color images that uses the RGB(red,green,and blue)color model and is based on bi-histogram shifting and image adjustment.Bi-histogram shifting is used to embed data and image adjustment to achieve contrast enhancement by adjusting the images resulting from each channel of the color images before combining them to generate the final enhanced image.Images are first divided into three channels-R,G,and B-and the Max,Med,and Min channels are then determined from these.Before histogram shifting,some calculations are done to determine how many iterations there will be for each channel.The images are adjusted to improve visual quality in the enhanced images after data has been embedded in each channel.The experimental results show that the enhanced images produced by the proposed method are qualitatively and aesthetically superior to those produced by some earlier methods,and their quality was assessed using PSNR,SSIM,RCE,RMBE,and CIEDE2000.The embedding rate obtained by the suggested method is acceptable. 展开更多
关键词 contrast enhancement bi-histogram shifting image adjustment
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Aggregation-induced T_(1)/T_(2) contrast enhancement for magnetic resonance imaging-guided intraoperative surgery
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作者 Wenbo Sun Bin Yu +5 位作者 Dianshuai Huang Chunhuan Jiang Wei Wang Jianhua Liu Zonghua Wang Lehui Lu 《Science China Chemistry》 SCIE EI CAS CSCD 2024年第6期2046-2055,共10页
Magnetic resonance imaging(MRI)plays an important role in precision medicine that is hampered by the lack of contrast agents with high efficiency and the ability to translate diagnostic accuracy into therapeutic inter... Magnetic resonance imaging(MRI)plays an important role in precision medicine that is hampered by the lack of contrast agents with high efficiency and the ability to translate diagnostic accuracy into therapeutic intervention.Herein,we demonstrate a DNA-based MRI probe that overcomes previous single-mode enhancement and provides a mechanism of action for aggregationinduced dual-modal MRI signal enhancement.A facile method is developed to produce aggregated T_(1)/T_(2)dual-modal NaGdF_(4):Dy@PDA-DNA(PDA=polydopamine)MRI probes.When aggregated,this probe can further amplify MRI signal intensity and exhibit improved geometrical and positional stability in vivo.The performance of the NaGdF_(4):Dy@PDA-DNA MRI probe toward MRI-guided preoperative planning and visualization-guided surgery is verified using an orthotopic tumor-bearing mouse model.The result shows that the rapid metabolism of the degraded probe leads to the mitigation of long-term toxic effects.Therefore,the developed high-performance MRI probe is of great significance for enhancing MRI diagnostic accuracy into precision medical therapeutic interventions. 展开更多
关键词 MRI probe DNA aggregation-induced T_(1)/T_(2)contrast enhancement precision medicine degradable probe
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High-Stability High-Energy Picosecond Optical Parametric Chirped Pulse Amplifier as a Preamplifier in Nd:Glass Petawatt System for Contrast Enhancement 被引量:1
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作者 黄庭瑞 潘雪 +3 位作者 张鹏 王江峰 欧阳小平 李学春 《Chinese Physics Letters》 SCIE CAS CSCD 2017年第6期53-57,共5页
We demonstrate a novel picosecond optical parametric preamplification to generate high-stability, high-energy and high-contrast seed pulses. The 5ps seed pulse is amplified from 60pJ to 300μJ with an 8.6ps/ 3mJ pump ... We demonstrate a novel picosecond optical parametric preamplification to generate high-stability, high-energy and high-contrast seed pulses. The 5ps seed pulse is amplified from 60pJ to 300μJ with an 8.6ps/ 3mJ pump laser in a signal stage of short pulse non-collinear optical parametric chirped pulse amplification. The total gain is more than 106 and the rms energy stability is under 1.35%. The contrast ratio is higher than 10s within a scale of 20ps before the main pulse. Consequently, the improvement factor of the signal contrast is approximately equal to the gain 106 outside the pump window. 展开更多
关键词 High-Stability High-Energy Picosecond Optical Parametric Chirped Pulse Amplifier as a Preamplifier in Nd:Glass Petawatt System for contrast enhancement length Nd
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A Novel Approach for Enhancement of Geometric and Contrast Resolution Properties of Low Contrast Images
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作者 Koushlendra Kumar Singh Manish Kumar Bajpai Rajesh Kumar Pandey 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2018年第2期628-638,共11页
The present work encompasses a new image enhancement algorithm using newly constructed Chebyshev fractional order differentiator. We have used Chebyshev polynomials to design Chebyshev fractional order differentiator.... The present work encompasses a new image enhancement algorithm using newly constructed Chebyshev fractional order differentiator. We have used Chebyshev polynomials to design Chebyshev fractional order differentiator. We have generated the high pass filter corresponding to it. The designed filters are applied for decomposing the input image into four bands and low-low(L-L) sub-band is updated using correction coefficients. Reconstructed image with updated L-L sub-band provides the enhanced image. The visual results obtained are encouraging for image enhancement. The applicability of the developed algorithm is illustrated on three different test images.The effects of order of differentiation on the edges of images have also been presented and discussed. 展开更多
关键词 Index Terms-Chebyshev polynomial based approximation contrast enhancement fractional order differentiator.
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Feasibility and value of quantitative dynamic contrast enhancement MR imaging in the evaluation of sinonasal tumors 被引量:14
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作者 Xian Junfang Du Huarui +7 位作者 Wang Xinyan Yan Fei Zhang Zhengyu Hao Hui Zhao Bo Tong Yajian Zhang Jue Han Demin 《Chinese Medical Journal》 SCIE CAS CSCD 2014年第12期2259-2264,共6页
Background Quantitative dynamic contrast enhancement MR imaging (DCE-MRI),used to measure properties of tissue microvasculature and tumor angiogenesis,is a promising method for distinguishing benign and malignant tu... Background Quantitative dynamic contrast enhancement MR imaging (DCE-MRI),used to measure properties of tissue microvasculature and tumor angiogenesis,is a promising method for distinguishing benign and malignant tumors and characterizing tumor response to antiangiogenic treatment.The aim of this study was to assess the feasibility of quantitative parameters derived from clinically used DCE-MRI for distinguishing benign from malignant tumors in the sinonasal area,which may be potentially useful for prediction and monitoring of treatment response to chemoradiotherapy of sinonasal tumors.Methods One hundred and forty-three patients with sinonasal tumors,including 78 malignant tumors and 65 benign tumors and tumor-like lesions,underwent clinically used DCE-MRI.Parametric maps were obtained for quantitative parameters including Ktrans,kep and ve.Two radiologists reviewed these maps and measured Ktrans,kep and ve in the tumor tissue.Data were analyzed using independent T-test or Mann-Whitney U test analysis and receiver operating characteristic curves.Results Ktrans,kep and ve showed significant differences between benign and malignant tumors in the sinonasal area (P=-0.000 1).The accuracy of Ktrans,kep and ve in differentiation between benign and malignant sinonasal tumors were 72.0%,76.2% and 67.1%,respectively.There were significant differences in kep and ve between malignant epithelial sinonasal tumors and lymphomas (P <0.05).Using a ve value of 0.213 as the threshold value differentiated malignant epithelial tumors from lymphomas with an accuracy of 78.3%,sensitivity of 88.2%,specificity of 68.0%,positive predictive value of 66.7%,and negative predictive value of 90.9%.However,no significant difference in Ktrans and kep was found between malignant epithelial and non-epithelial tumors in the sinonasal area (P >0.05).Conclusions It is feasible that quantitative parameters of tumors can be derived from clinically used DCE-MRI in the sinonasal region.Preliminary findings suggest an increased value for quantitative DCE-MRI in the evaluation of sinonasal tumors in clinical practice. 展开更多
关键词 nasal cavity paranasal sinus NEOPLASM cancer quantitatively dynamic contrast enhanced scanning magnetic resonance imaging
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Dynamic contrast enhanced ultrasound in differential diagnosis of hepatocellular carcinoma: A systematic review and meta-analysis
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作者 Giorgio Esposto Paolo Santini +5 位作者 Fabrizio Termite Linda Galasso Irene Mignini Maria Elena Ainora Antonio Gasbarrini Maria Assunta Zocco 《World Journal of Gastrointestinal Oncology》 SCIE 2024年第6期2804-2815,共12页
BACKGROUND Non-invasive differential diagnosis between hepatocellular carcinoma(HCC)and other liver cancer(i.e.cholangiocarcinoma or metastasis)is highly challenging and definitive diagnosis still relies on histologic... BACKGROUND Non-invasive differential diagnosis between hepatocellular carcinoma(HCC)and other liver cancer(i.e.cholangiocarcinoma or metastasis)is highly challenging and definitive diagnosis still relies on histological exam.The patterns of enhancement and wash-out of liver nodules can be used to stratify the risk of malignancy only in cirrhotic patients and HCC frequently shows atypical features.Dynamic contrast-enhanced ultrasound(DCEUS)with standardized software could help to overcome these obstacles,providing functional and quantitative parameters and potentially improving accuracy in the evaluation of tumor perfusion.AIM To explore clinical evidence regarding the application of DCEUS in the differential diagnosis of liver nodules.METHODS A comprehensive literature search of clinical studies was performed to identify the parameters of DCEUS that could relate to histological diagnosis.In accordance with the study protocol,a qualitative and quantitative analysis of the evidence was planned.RESULTS Rise time was significantly higher in HCC patients with a standardized mean difference(SMD)of 0.83(95%CI:0.48-1.18).Similarly,other statistically significant parameters were mean transit time local with a SMD of 0.73(95%CI:0.20-1.27),peak enhancement with a SMD of 0.37(95%CI:0.03-0.70),area wash-in area under the curve with a SMD of 0.47(95%CI:0.13-0.81),wash-out area under the curve with a SMD of 0.55(95%CI:0.21-0.89)and wash-in and wash-out area under the curve with SMD of 0.51(95%CI:0.17-0.85).SMD resulted not significant in fall time and wash-in rate,but the latter presented a trend towards greater values in HCC compared to intrahepatic cholangiocarcinoma.CONCLUSION DCEUS could improve non-invasive diagnosis of HCC,leading to less liver biopsy and early treatment.This quantitative analysis needs to be applied on larger cohorts to confirm these preliminary results. 展开更多
关键词 Dynamic contrast enhanced ultrasound Hepatocellular carcinoma Intracellular cholangiocarcinoma Quantitative ultrasound Liver cancer Time-intensity curve
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Evaluation of quantitative contrast harmonic imaging to assess malignancy of liver tumors:A prospective controlled two-center study 被引量:15
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作者 EM Jung DA Clevert +5 位作者 AG Schreyer S Schmitt J Rennert R Kubale S Feuerbach F Jung 《World Journal of Gastroenterology》 SCIE CAS CSCD 2007年第47期6356-6364,共9页
AIM: To establish the extent to which contrast enhancement with SonoVue in combination with quantitative evaluation of contrast-medium dynamics facilitates the detection of hepatic tumors. METHODS: One hundred patient... AIM: To establish the extent to which contrast enhancement with SonoVue in combination with quantitative evaluation of contrast-medium dynamics facilitates the detection of hepatic tumors. METHODS: One hundred patients with histologically confirmed malignant or benign hepatic tumor (maximum size 5 cm) were analyzed. Contrast-enhanced ultrasound (bolus injection 2.5 mL SonoVue) was carried out with intermittent breath-holding technique using a multifrequency transducer (2.5-4 MHz). Native vascularization was analyzed with power Doppler. The contrast-enhanced dynamic ultrasound investigation was carried out with contrast harmonic imaging in true detection mode during the arterial,portal venous and late phases. Mechanical index was set at 0.15. Perfusion analysis was performed by post-processing of the raw data time intensity curve (TIC) analysis. The cut-off of the gray value differences between tumor and normal liver tissue was established using Receiver Operating Characteristic (ROC) analysis 64-line multi-slice computed tomography served as reference method in all cases. Magnetic resonance tomography was used additionally in 19 cases. RESULTS: One hundred patients with 59 malignant (43 colon,5 breast,2 endocrine metastases,7 hepatocellular carcinomas and 2 kidney cancers) and 41 benign (15 hemangiomas,7 focal nodular hyperplasias,5 complicated cysts,2 abscesses and 12 circumscribed fatty changes) tumors were included. The late venous phase proved to be the most sensitive for classification of the tumor type. Fifty-eight of the 59 malignant tumors were classified as true positive,and one as false negative. This resulted in a sensitivity of 98.3%. Of the 41 benign tumors,37 were classified as true negative and 4 as false negative,which corresponds to a specificity of 90.2%. Altogether,95.0% of the diagnoses were classified as correct on the basis of the histological classification. No investigator-dependency (P = 0.23) was noted. CONCLUSION: The results show the possibility of accurate prediction of malignancy of hepatic tumors with a positive prognostic value of 93.5% using advanced contrast-enhanced ultrasound. Contrast enhancement with SonoVue in combination with quantitative evaluation of contrast-medium dynamics is a valuable tool to discriminate hepatic tumors. 展开更多
关键词 Liver tumors Malignant tumor contrast harmonic imaging Quantitative contrast enhancement
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Statistical Histogram Decision Based Contrast Categorization of Skin Lesion Datasets Dermoscopic Images 被引量:1
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作者 Rabia Javed Mohd Shafry Mohd Rahim +3 位作者 Tanzila Saba Suliman Mohamed Fati Amjad Rehman Usman Tariq 《Computers, Materials & Continua》 SCIE EI 2021年第5期2337-2352,共16页
Most of the melanoma cases of skin cancer are the life-threatening form of cancer.It is prevalent among the Caucasian group of people due to their light skin tone.Melanoma is the second most common cancer that hits th... Most of the melanoma cases of skin cancer are the life-threatening form of cancer.It is prevalent among the Caucasian group of people due to their light skin tone.Melanoma is the second most common cancer that hits the age group of 15–29 years.The high number of cases has increased the importance of automated systems for diagnosing.The diagnosis should be fast and accurate for the early treatment of melanoma.It should remove the need for biopsies and provide stable diagnostic results.Automation requires large quantities of images.Skin lesion datasets contain various kinds of dermoscopic images for the detection of melanoma.Three publicly available benchmark skin lesion datasets,ISIC 2017,ISBI 2016,and PH2,are used for the experiments.Currently,the ISIC archive and PH2 are the most challenging and demanding dermoscopic datasets.These datasets’pre-analysis is necessary to overcome contrast variations,under or over segmented images boundary extraction,and accurate skin lesion classification.In this paper,we proposed the statistical histogram-based method for the pre-categorization of skin lesion datasets.The image histogram properties are utilized to check the image contrast variations and categorized these images into high and low contrast images.The two performance measures,processing time and efficiency,are computed for evaluation of the proposed method.Our results showed that the proposed methodology improves the pre-processing efficiency of 77%of ISIC 2017,67%of ISBI 2016,and 92.5%of PH2 datasets. 展开更多
关键词 CANCER healthcare contrast enhancement dermoscopic images skin lesion low contrast images WHO
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Quantitative Assessment of the Effect of Nitric Oxide Synthase Inhibition on Tumor Vascular Activity Using Dynamic Contrast-Enhanced Computed Tomography 被引量:1
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作者 Kenya Murase Yoshinori Kusakabe Shohei Miyazaki 《Open Journal of Medical Imaging》 2016年第2期42-52,共12页
Purpose: The purpose of this study was to develop a method to quantitatively assess the effect of nitric oxide synthase (NOS) inhibition on tumor vascular activity using dynamic contrast-enhanced computed tomography (... Purpose: The purpose of this study was to develop a method to quantitatively assess the effect of nitric oxide synthase (NOS) inhibition on tumor vascular activity using dynamic contrast-enhanced computed tomography (DCE-CT) and to investigate its usefulness using animal experiments. Mate-rials and Methods: The DCE-CT studies were performed in anesthetized Fisher rats bearing tumors using a 4-row multi-slice CT. The scanning started 4 s before a bolus injection of iodinated contrast agent (CA) (150 mgI/kg) from the tail vein using an automatic injector and lasted 60 s at 1-s in-tervals. The contrast enhancement (CE) images were generated by subtracting the CT images before and after the administration of CA. First, the DCE-CT studies were performed before and 15, 30, and 45 min after administration of N-nitro-L-arginine (L-NNA) (1, 3, and 10 mg/kg) or vehicle, and the relative CE values were calculated by normalizing the CE image at each time point by that obtained from the first DCE-CT study. Second, we investigated the case when L-arginine (L-ARG) (200 mg/kg) and L-NNA (1, 3, and 10 mg/kg) were administered after the first and second DCE-CT studies, respectively. Third, we investigated the case when L-NNA (1, 3, and 10 mg/kg) and L-ARG (200 mg/kg) were administered after the first and second DCE-CT studies, respectively. Finally, we investigated the case when L-NNA (1, 3, and 10 mg/kg) and L-ARG (200 mg/kg) were administered simultaneously after the first DCE-CT study. Results: The relative CE value significantly decreased after L-NNA administration in a dose-dependent manner (p-values = 0.0074 and <0.0001 for 0 vs. 3 mg/kg and 0 vs. 10 mg/kg, respectively, at 15 min, 0.0003 and <0.0001 for 0 vs. 3 mg/kg and 0 vs. 10 mg/kg, respectively, at 30 min, and 0.0367 and 0.0004 for 0 vs. 3 mg/kg and 0 vs. 10 mg/kg, respectively, at 45 min). When L-ARG was administered prior to the administration of 1 mg/kg L-NNA, the relative CE value at 45 min was significantly higher than that at 15 min. When L-ARG was administered after L-NNA administration, there was no significant difference between the relative CE values at 15 min and 45 min. These results suggest that when using L-NNA in combination with L-ARG, their effect on tumor vascular activity differs depending on the order of their administration. When L-NNA and L-ARG were administered simultaneously, there was a tendency for the relative CE value to be higher than that when only L-NNA was administered, at all injected doses of L-NNA. Conclusion: Our method using DCE-CT is useful for monitoring the effect of NOS inhibition on tumor vascular activity and for determining the optimal injected dose and timing of NOS inhibitors for anticancer therapy. 展开更多
关键词 Nitric Oxide Synthase N-Nitro-L-Arginine L-ARGININE Tumor Vascular Activity Dynamic contrast-Enhanced Computed Tomography contrast enhancement
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A New Method for Human Microcirculation Image Enhancement 被引量:1
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作者 CHEN Yuan ZHAO Zhi-min LIU Lei LI Peng 《Chinese Journal of Biomedical Engineering(English Edition)》 2008年第4期153-160,共8页
Microcirculation images often have uneven illumination and low contrast in the acquisition process, which affect the image reorganization and following process. This paper presents a new method for microcireulatory im... Microcirculation images often have uneven illumination and low contrast in the acquisition process, which affect the image reorganization and following process. This paper presents a new method for microcireulatory image illumination correction and contrast enhancement based on the Contourlet transform. Initially, the image illumination model is extracted by Contourlet transform and then uneven illumination is corrected. Next, in order to restrain noise and enhance image contrast, the probability function associated with noise coefficient and edge coefficient is established and applied to all Contourlet coefficients. Then, a nonlinear enhancement function is applied to modified Contourlet coefficient to adaptively enhance image contrast. Finally, the enhanced image is obtained by inverse Contourlet transform. We compare this approach with other contrast enhancement methods, result showing that our method has a better effect than other enhancement methods, which might be helpful for clinical diagnostics of microcirculation. 展开更多
关键词 MICROCIRCULATION illumination correction noise restrain contrast enhancement contourlct transform
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A Post-Processing Algorithm for Boosting Contrast of MRI Images
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作者 B.Priestly Shan O.Jeba Shiney +3 位作者 Sharzeel Saleem V.Rajinikanth Atef Zaguia Dilbag Singh 《Computers, Materials & Continua》 SCIE EI 2022年第8期2749-2763,共15页
Low contrast of Magnetic Resonance(MR)images limits the visibility of subtle structures and adversely affects the outcome of both subjective and automated diagnosis.State-of-the-art contrast boosting techniques intole... Low contrast of Magnetic Resonance(MR)images limits the visibility of subtle structures and adversely affects the outcome of both subjective and automated diagnosis.State-of-the-art contrast boosting techniques intolerably alter inherent features of MR images.Drastic changes in brightness features,induced by post-processing are not appreciated in medical imaging as the grey level values have certain diagnostic meanings.To overcome these issues this paper proposes an algorithm that enhance the contrast of MR images while preserving the underlying features as well.This method termed as Power-law and Logarithmic Modification-based Histogram Equalization(PLMHE)partitions the histogram of the image into two sub histograms after a power-law transformation and a log compression.After a modification intended for improving the dispersion of the sub-histograms and subsequent normalization,cumulative histograms are computed.Enhanced grey level values are computed from the resultant cumulative histograms.The performance of the PLMHE algorithm is comparedwith traditional histogram equalization based algorithms and it has been observed from the results that PLMHE can boost the image contrast without causing dynamic range compression,a significant change in mean brightness,and contrast-overshoot. 展开更多
关键词 contrast enhancement histogram equalisation image quality magnetic resonance imaging medical image analysis POST-PROCESSING
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Evaluation of Large Intracranial Aneurysms with Cine MRA and 3D Contrast-Enhanced MRA
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作者 朱文珍 冯定义 +2 位作者 漆剑频 夏黎明 王承缘 《Journal of Huazhong University of Science and Technology(Medical Sciences)》 SCIE CAS 2004年第1期95-98,106,共5页
The value of combined application of both ECG gated cine MRA and 3D CEMRA in the detection of large intracranial aneurysms was evaluated and the findings were compared with those of conventional MRA and DSA. Twenty ... The value of combined application of both ECG gated cine MRA and 3D CEMRA in the detection of large intracranial aneurysms was evaluated and the findings were compared with those of conventional MRA and DSA. Twenty four patients with 26 large intracranial aneurysms underwent MRI and DSA. All these aneurysms, diameter from 15 to 39 mm, were located at internal cerebral artery ( n= 12), vertebral artery ( n= 3), basilar artery ( n= 4), anterior cerebral artery ( n= 2), middle cerebral artery ( n= 2), anterior communicate artery ( n= 2) and posterior communicate artery ( n= 1). Thirteen cases of hematoma or cavernoma were studied as control group. All patients were examined on GE 1.5T MR system. ECG gated cine MRA was performed with 2D multi phase fast gradient recalled echo sequence in a single section. All the images were analyzed with signal intensity VS time curve for differentiating intraaneurysmal blood flow from static tissue. The results were analzsed by statistic ' t ' test. 3D CEMRA was performed with spoiled gradient recalled echo and one dose of Gd DTPA. All data was processed with multi plannar reformat (MPR) and tomography for the demonstration of aneurysms in detail. All 26 aneurysms were demonstrated successfully by combined application of both cine MRA and 3D CEMRA. Compared to DSA and conventional 3D MOTSA, its sensitivity and specificity figures were both 100 %. Cine MRA could differentiate the blood flow from the static tissue. The intensity VS time curves of intraaneurysmal blood flow offered fluctuating form and average signal change between systole and diastole period was about 89.8±37.4; However, under the control group, intraaneurysmal thrombus or cerebral hemorrhage or cavernomas had no significant signal change and the curves offered steady form with the average signal change being about 8.2±6.3. There was statistically significant difference between the intraaneurysmal blood flow and static tissue ( P =0.025, <0.05). 3D CEMRA was very useful in demonstrating the aneurysmal size, intraaneurysmal thrombus formation, neck and the detailed relationship of the aneurysm to the surrounding structures. It was concluded that the combined application of both cine MRA and 3D CEMRA might be a valuable clinical tool for the detection of large intracranial aneurysms. 展开更多
关键词 ANEURYSM BRAIN MRA contrast enhancement
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