一种改进的中值滤波算法

为了更好的对原始图像进行除噪,本文针对经典中值滤波方法的缺点对其进行改进。将高斯加权与中值滤波方法进行结合,提出一种新的滤波方法。分别用本文方法与中值滤波方法在带有不同噪声的图像上进行除噪实验,对实验结果进行分析比较并利用均方误差来定量比较。实验结果表明,本文提出的方法比经典中值滤波方法更具普适性。     

用于立体数字信息恢复的DFT域三维滤波器设计

为有效地重现立体数字信息，本文提出一种离散傅立叶变换DFT（Discrete Fourier Transform）域三雏滤波器的设计方法。此方法充分考虑了各种三维频率分布和时域分布的因素，把DFT、全相位信号处理、频谱分析等性质结合了起来，构造出性能较好的三雏滤波器。弥补了部分现有的用二维方法解决三维滤波问题的不足，具有理论价值和应用前景。     

On the frontline of screening for breast cancer

The mainstay of screening for breast cancer is the mammogram. There are several randomized control trials that demonstrate a significant decrease in breast cancer mortality when compared to women without screening mammography included in their care. Digital mammography has improved detection in the dense breast. With the introduction of digital mammography, other novel techniques such as stereo digital mammography (SDM) and tomosynthesis can reduce recall significantly without a negative effect on cancer detection. Magnetic resonance imaging (MRI) and ultrasound added to mammography can improve cancer detection for high-risk women but can have false positive consequences.     

Improved HPLC-ECD analysis of mitomycin C, porfiromycin, VP 16-213 and VM 26 by implantation of software filters

In high performance liquid chromatography with electrochemical detection (HPLC/ECD) much attention has been paid to the performance of the applied detection system with respect to reliability and sensitivity. In general, insufficient attention has been paid to relatively easy to implant devices for improved collection and handling of detection signals. Four models of software filtering are studied and compared with hardware filtering. In the investigated chromatographic-electrochemical system, off-line parabolic filtering after on-line averaging of sixteen measurements proved to be the system of first choice, with respect to execution time, noise level, signal to noise ratio, peak height and resolution.     

Mammography utilization after a benign breast biopsy among Hispanic and non-Hispanic women

BACKGROUND: In spite of the effectiveness of mammography screening for early detection of breast carcinoma, the use of screening mammography varies widely across racial and ethnic groups. Recently, concerns have been raised about the potential adverse effect a benign breast biopsy may have on subsequent mammography utilization, including subsequent use among minority women. METHODS: Computerized health care claims data for 1991 through 1997 from a managed care organization were used to compare mammography use among Hispanic and non-Hispanic women who had had a mammogram followed by an incisional or excisional benign breast biopsy to women who had had a mammogram and no biopsy. Through survival analysis methods, the time-to-next mammogram was compared among these three groups. RESULTS: The sample included 693 (3.2%) and 289 (1.3%) women who had had a mammogram followed by an incisional biopsy or an excisional biopsy, respectively, and 20,540 (95.4%) women who had had a mammogram and no biopsy. Both Hispanic and non-Hispanic women with a biopsy returned sooner for subsequent mammograms than women without a biopsy (P < 0.0001). Hispanic women without a biopsy returned later than non-Hispanic women without a biopsy (P < 0.0001). However, Hispanic women with an excisional biopsy returned sooner than non-Hispanic women (P < 0.05). CONCLUSIONS: Within a managed care organization, both Hispanic and non-Hispanic women who had had a mammogram followed by a benign breast biopsy returned sooner for a subsequent mammogram than women who had had a mammogram and no biopsy. However, ethnic differences in time-to-next mammogram were observed for women without a biopsy and those with an excisional biopsy. Hispanic women without a biopsy returned later for a subsequent mammogram than non-Hispanic women in similar groups, but those with an excisional biopsy returned sooner.     

The Architectural Design of Deblocking Filter for Image Enhancement in the Diagnosis of Cancer

Objective: This method is to reduce the risk of imprecise diagnosis associated with poor-quality CT images, thispaper presents a new technique designed to enhance the quality of medical CT images. The main objective is to improvethe appearance of CT images in order to obtain better visual interpretation and analysis, which is expected to ease thediagnosis process. The proposed technique involves applying a deblocking filter is to enhance the visual nature of apicture by diminishing the blocking artifacts. The appearance of a picture isn’t clear while an antique happens. Theproposed deblocking filter calculation gives a strategy to expel the ancient rarities by smoothing the sharp edges of apicture. Methods: With a specific goal to lessen the quantity of information access, multifaceted nature and consequentlyto upgrade the proficiency, a six-staged pipelined structure for picture pixels are proposed. Besides, to enhance thesubjective and target nature of a picture the deblocking filter performs identification of the antique at the coded squarelimits and weakens them by applying a chose filter. Result: The proposed algorithm is implemented in HDL using XilinxFPGA. The input image is converted into decimal pixel values using Matlab and this value is used as the input in HDL.The proposed algorithm is compared with other blocking algorithms. Conclusion: To design an effective deblockingfilter with low cost, low complexity and high intensity, pipeline based systems are used. In addition to that the numberof memory accesses and timing efficiency also be reduced using this method. The deblocking filtering operations canalso easily perform in parallel on multiple processors by using six-stage of pipelined, two-line deblocking filter. Theparameter mean, variance, standard deviation, resolution, contrast and PSNR values are compared with the previousmethod. Hence it shows the implementation of deblocking filter using pipelining is more efficient than others.     

Why do large breast cancers still present in a population offered screening?

Rates of large breast cancers should decrease in a population that is offered mammography screening, but women continue to present with them. We sought an explanation in a population-based epidemiological study of 1,459 women diagnosed with invasive breast cancer in 2002-2003 in Australia; breast cancers were > or =2 cm in 766 women (53%) and 11-1.9 cm in a comparison group (693, 47%). We interviewed the women about their personal, mammogram and breast histories in the years before diagnosis and collected biological characteristics of tumors and mammogram dates from medical records. The strongest correlate of breast cancer size at diagnosis was the method of detection: the odds of a > or =2 cm breast cancer was substantially lower for detection by a screening mammogram (OR = 0.27, 95% CI 0.21-0.34; p < 0.001) than for detection after a breast symptom. Higher BMI (ORs approximately 1.6 for > or =25 kg/m(2)), higher cancer grade (ORs of 1.6 for moderate, 2.89 for high grade) and lobular type (OR 2.09, 95% CI 1.45-3.0) were also independent correlates (p < 0.001) of a > or =2 cm breast cancer. HRT use strongly reduced the odds but only in cancers detected after a breast symptom (OR = 0.49, 95% CI 0.33-0.74; p = 0.002), not in those detected by a screening mammogram. As assessed from their proportional contribution to > or =2 cm breast cancers in our study population, lack of mammogram detection, BMI > or =25 kg/m(2) and moderate or high grade of the cancer were the most important factors with population attributable fractions of 42%, 11% and 29% respectively; the first 2 are amenable to intervention.     

The adverse implications of the transition from film to digital mammography for performing surveillance in patients with a history of breast cancer or significant risk factors for the disease

Aim: The transition from screen‐film to digital mammography at Peter MacCallum Cancer Centre was investigated, considering the impact on patient management and resource utilization. Methods: A retrospective comparison of the imaging outcomes of the last year of screen‐film and the first year of digital mammography was performed. The study group of 692 patients, all with a history or a significant risk factor of breast cancer, underwent a surveillance mammogram in both periods, enabling serial comparison of imaging outcomes on the same patient. Results: Overall 92 patients required a total of 125 further investigations after their film mammogram due to a mammographic abnormality while 130 underwent a total of 202 additional investigations after their digital mammogram. This is a significant increase in the number of patients further investigated (Fisher's exact test P = 0.005). However, the positive predictive value of further investigation finding a tumor after digital mammography was not significantly higher than that of film mammography (7.4 vs 6.5%, Fisher's exact test P = 0.57). There was a 44% increase in the cost of additional investigations during the first year of digital mammography compared to the previous year and an associated increase in hospital visits for patients. Conclusion: For patients undergoing annual surveillance mammography at Peter MacCallum Cancer Centre, the transition from film to digital mammography was found to be associated with an increase in both the number of additional investigations performed and in the number of hospital visits. The findings of this study should be considered when conversions from film to digital mammography are planned, specifically in terms of cost allocations and the burden on patient services in radiology and outpatient departments.     

Combination of digital mammography with semi-automated 3D breast ultrasound

This paper describes work aimed at combining 3D ultrasound with full-field digital mammography via a semi-automatic prototype ultrasound scanning mechanism attached to the digital mammography system gantry. Initial efforts to obtain high x-ray and ultrasound image quality through a compression paddle are proving successful. Registration between the x-ray mammogram and ultrasound image volumes is quite promising when the breast is stably compressed. This prototype system takes advantage of many synergies between the co-registered digital mammography and pulse-echo ultrasound image data used for breast cancer detection and diagnosis. In addition, innovative combinations of advanced US and X-ray applications are being implemented and tested along with the basic modes. The basic and advanced applications are those that should provide relatively independent information about the breast tissues. Advanced applications include x-ray tomosynthesis, for 3D delineation of mammographic structures, and non-linear elasticity and 3D color flow imaging by ultrasound, for mechanical and physiological information unavailable from conventional, non-contrast x-ray and ultrasound imaging.     

Breast Cancer Detection using Crow Search Optimization based Intuitionistic Fuzzy Clustering with Neighborhood Attraction

Objective: Generally, medical images contain lots of noise that may lead to uncertainty in diagnosing theabnormalities. Computer aided diagnosis systems offer a support to the radiologists in identifying the disease affectedarea. In mammographic images, some normal tissues may appear to be similar to masses and it is tedious to differentiatethem. Therefore, this paper presents a novel framework for the detection of mammographic masses that leads toearly diagnosis of breast cancer. Methods: This work proposes a Crow search optimization based Intuitionistic fuzzyclustering approach with neighborhood attraction (CrSA-IFCM-NA) for identifying the region of interest. First ordermoments were extracted from preprocessed images. These features were given as input to the Intuitionistic fuzzyclustering algorithm. Instead of randomly selecting the initial centroids, crow search optimization technique is appliedto choose the best initial centroid and the masses are separated. Experiments are conducted over the images taken fromthe Mammographic Image Analysis Society (mini-MIAS) database. Results: CrSA-IFCM-NA effectively separatedthe masses from mammogram images and proved to have good results in terms of cluster validity indices indicatingthe clear segmentation of the regions. Conclusion: The experimental results show that the accuracy of the proposedmethod proves to be encouraging for detection of masses. Thus, it provides a better assistance to the radiologists indiagnosing breast cancer at an early stage.     

Validity and Reliability of Health Belief Model Questionnaire for Promoting Breast Self-examination and Screening Mammogram for Early Cancer Detection

Background: Early detection of breast cancer is essential in improving overall women’s health. The researchers sought to develop a comprehensive measure that combined the basic components of the health belief model (HBM) with a focus on breast self-examination (BSE) and screening mammogram amongst women.Methods: Questionnaire items were developed following a review of relevant literature of HBM on BSE and screening mammogram. The sampling frame for the study was Malaysian women aged 35 to 70 years old, living in Kuantan, Pahang and able to read or write in Bahasa Malaysia or English. As such, 103 women were randomly selected to participate in the study. Tests of validity using exploratory factor analysis (EFA) and reliability were subsequently performed to determine the psychometric properties of the questionnaire. Results: The EFA revealed nine factors (self-efficacy of mammogram, perceived barriers of BSE and mammogram, perceived susceptibility of breast cancer, perceived severity of breast cancer, cues to action for mammogram screening, perceived benefits of BSE, health motivation, perceived benefits of mammogram and self-efficacy of BSE) containing 54 items that jointly accounted for 74.2% of the observed variance. All nine factors have good internal consistency with Cronbach’s alpha ≥ 0.8. Fifty-four items remained in the final questionnaire after deleting 13 problematic items. The scale also showed good convergent and discriminant validity.Conclusion: The findings showed that the designed questionnaire was a valid and reliable instrument for the study involving women in Kuantan, Pahang. The instrument can help to assess women’s beliefs on BSE adoption and mammogram screening in health care practice and research.     

A New Breast Border Extraction and Contrast Enhancement Technique with Digital Mammogram Images for Improved Detection of Breast Cancer

Purpose: Breast cancer can be cured if diagnosed early, with digital mammography which is one of the mosteffective imaging modalities for early detection. However mammogram images often come with low contrast, highbackground noises and artifacts, making diagnosis difficult. The purpose of this research is to preprocess mammogramimages to improve results with a computer aided diagnosis system. The focus is on three preprocessing methods: a breastborder segmentation method; a contrast enhancement method; and a pectoral muscle removal method. Methods: Theproposed breast border extraction method employs a threshold based segmentation technique along with a combinationof morphological operations. The contrast enhancement method presented here is divided into two phages. In phaseI, a bi-level histogram modification technique is applied to enhance the image globally and in phase II a non-linearfilter based on local mean and local standard deviation for each pixel is applied to the histogram modified image. Thepectoral muscle removal method discussed here is implemented by applying a region growing algorithm. Results:The proposed techniques are tested with the Mini MIAS dataset. The breast border extraction method is applied to322 images and achieved 98.7% segmentation accuracy. The contrast enhancement method is evaluated based onquantitative measures like measure of enhancement, absolute mean brightness error, combined enhancement measureand discrete entropy. The proposed contrast enhancement method when applied to 14 images with different types ofmasses, the quantitative measures showed an optimum level of contrast enhancement compared to other enhancementmethods with preservation of local detail. Removal of the pectoral muscle from MLO mammogram images reducedthe search region while identifying abnormalities like masses and calcification. Conclusions: The preprocessing stepsproposed here show promising results in terms of both qualitative and quantitative analysis.     

The Usage and Knowledge of Mammogram among Women inSub-Urban Area in Terengganu,Malaysia

Introduction: Breast cancer is the leading cancer in women today and the major challenge is late presentationthen later contributes to poor outcome and high fatality rate. Mammography is effective in early detection ofbreast cancer and consequently significantly improves the breast cancer survival. Materials and Methods: Thiscross-sectional study was used to study the knowledge and awareness towards mammogram amongst womenaged 15 years old and above. A systemic random sampling was applied and information gathered through guidedinterview by using a structured questionnaire. Results: Eighty-six respondents were recruited. The mean age ofrespondents was 40.5 years (SD: 15.51) and more than 80% had secondary and tertiary level of education. Thepercentage of respondents ever performed mammogram was 10.5% (95% CI: 4.0%-17.0%). The rate of correctanswers was between 8.1% and 48.8%. Most of the respondents do not sure the answer (45.3%-61.6%) ratherthan wrongly answer (4.7%-43.0%). Only about 8% truly answer that mammogram should be done once in alife. There are 10.5% of women claimed that mammogram had no serious side effect and not a painful procedure.Nearly half of respondents (48.8%) correctly mentioned that Mammogram can detect breast cancer in earlystage. Conclusion: Only a small percentage of women ever performed mammogram and there are seriouslyunaware and poor knowledge pertaining to mammography screening for breast cancer among women in suburban area. A massive health education campaign through multiple methods and agencies are needed to enhancethe knowledge and awareness on mammogram.     

Quantitative assessment of percent breast density: analog versus digital acquisition

Breast density is a moderate risk factor for breast cancer based on quantitative measurement of percent breast density from film-screen mammograms. In this study, percent breast density was determined using computer-assisted interactive thresholding software from sixty consecutive mammograms of women undergoing digital screening mammography with a prior film-screen mammogram obtained within the last two years. Observations were made regarding discrepancies in density readings. Percent breast density was significantly lower for digital mammograms (mean 32.2%) compared to analog mammograms (mean 40.3%) (p<0.0001). This was not significant for women with less than 20% breast density (range +0.3 to -2.7%), but larger differences were seen with increasing density (12.5-14.9% lower for >50% density). Differences in density readings between analog and digital mammography were largely observed to be due to better recognition of the skin line on digital mammograms resulting in inclusion of more subcutaneous fat. Difficulties with appropriate recognition of subcutaneous breast tissue and fatty tissue near the chest wall were present for both analog and digital mammography. In conclusion, percent breast density is significantly lower when the mammogram is acquired in digital format compared to film-screen, largely due to better recognition of the skin line with resultant inclusion of more subcutaneous fat. Breast cancer risk predictions based on computerized assessment of breast density may be underestimated when applied to digital mammography.     

一种视频编码中去低照度噪声方法

提出了一种消除低照度、中慢速运动视频序列中噪声的方法。在编码的不同阶段采取不同的滤波方法：在预测编码阶段，对于帧内块利用空域相关信息采取高斯去噪方法，对于帧间块利用时域相关信息采取运动补偿去噪策略；在变换编码阶段，采取8×8整数DCT变换的方法。在量化中去除高频噪声。实验结果表明了方法的有效性，降低了码流。     

基于形态学重构运算的医学CT图像滤波方法

提出一种基于数学形态学开-闭重构的医学CT图像滤波方法。该方法合理选取不同尺度的结构元素和标记图像,利用数学形态学开-闭重构运算对图像进行滤波,解决了传统滤波方法处理医学CT图像时滤波效果差及模糊图像边缘信息的问题。仿真结果表明该方法在复杂噪声情况下能够有效滤除噪声并且边缘保持效果较好。     

Initial Australian experience with the recovery inferior vena cava filter in patients with increased risk of thromboembolic disease

Inferior vena cava (IVC) filters are an alternative treatment in venous thromboembolism where there are contraindications to anticoagulation. There are, however, concerns about the long-term safety of permanent IVC filters. Often, the period of risk from anticoagulation therapy is short, which supports the use of non-permanent IVC filters. In this series, 54 Recovery Filters (Bard, Tempe, AZ, USA) were placed since its approval for use in Australia in March 2004 (approved for removal up to 160 days after insertion). The most common indication for filter placement in this series was established thromboembolic disease with a temporary contraindication to anticoagulation. Twenty-two filters were successfully retrieved without complication. In one case, it was not possible to retrieve the filter because of extensive contained thrombus. No complication was experienced at filter placement or retrieval; however, a fatal complication occurred as a result of filter migration. Mean time from placement to retrieval was 48 days (range 7-90 days). We describe methods we found useful at filter retrieval to overcome filter tilting.     

Detection of malignant breast tumours in dense breast tissue: results of 99mTc-tetrofosmin scintimammography related to surgery.

AIMS: To assess the contribution of 99mTechnetium tetrofosmin (99mTc-TF) scintimammography for staging of breast lesions in patients with a suspicious or non-diagnostic mammogram to reduce unnecessary surgical procedures in future. METHODS: Fifty patients with suspicious physical examinations and/or mammography underwent 99mTc-TF breast imaging. RESULTS: Scintimammography with 99mTc-TF was positive in 37 patients (36 true positive, one false positive) and negative in 13 patients (12 true negative, one false negative). The detection of a malignant tumour by 99mTc-TF was independent of the density of the breast tissue. In 33 patients with a malignant breast tumour 99mTc-TF was diagnostic with respect to axillary status, but in four out of 19 patients with a histologically positive axillary lymph node status, tumour involvement remained undetected by scintigraphy. Moreover, in four patients, scintimammography revealed an additional discrete area of increased 99mTc-TF uptake, which proved to be second primary breast cancers. CONCLUSIONS: 99mTc-TF scintimammography appears to be an accurate diagnostic test in patients with a symptomatic breast lesion and a non-diagnostic mammogram, also in those patients with dense breast tissue. This procedure may also have potential for the detection of second primary breast cancers in an early stage.     

Accuracy of self-reported cancer-screening histories: a meta-analysis.

BACKGROUND: Survey data used to study trends in cancer screening may overestimate screening utilization while potentially underestimating existing disparities in use. METHODS: We did a literature review and meta-analysis of validation studies examining the accuracy of self-reported cancer-screening histories. We calculated summary random-effects estimates for sensitivity and specificity, separately for mammography, clinical breast exam (CBE), Pap smear, prostate-specific antigen testing (PSA), digital rectal exam, fecal occult blood testing, and colorectal endoscopy. RESULTS: Sensitivity was highest for mammogram, CBE, and Pap smear (0.95, 0.94, and 0.93, respectively) and lowest for PSA and digital rectal exam histories (0.71 and 0.75). Specificity was highest for endoscopy, fecal occult blood testing, and PSA (0.90, 0.78, and 0.73, respectively) and lowest for CBE, Pap smear, and mammogram histories (0.26, 0.48, and 0.61, respectively). Sensitivity and specificity summary estimates tended to be lower in predominantly Black and Hispanic samples compared with predominantly White samples. When estimates of self-report accuracy from this meta-analysis were applied to cancer-screening prevalence estimates from the National Health Interview Survey, results suggested that prevalence estimates are artificially increased and disparities in prevalence are artificially decreased by inaccurate self-reports. CONCLUSIONS: National survey data are overestimating cancer-screening utilization for several common procedures and may be masking disparities in screening due to racial/ethnic differences in reporting accuracy.     

Network Meta-analysis for the Diagnostic Approach to Pathologic Nipple Discharge

Pathologic nipple discharge (PND) is one of the most common breast-related complaints for referral because of its supposed association with breast cancer. The aim of this network meta-analysis (NMA) was to compare the diagnostic efficacy of ultrasound, mammogram, cytology, magnetic resonance imaging (MRI), and ductoscopy in patients with PND, as well as to determine the best diagnostic strategy to assess the risk of malignancy as cause for PND. Cochrane Library, PubMed, and Embase were searched to collect relevant literature from the inception of each of the diagnostic methods until January 27, 2020. The search yielded 1472 original citations, of which 36 studies with 3764 patients were finally included for analysis. Direct and indirect comparisons were performed using an NMA approach to evaluate the combined odd ratios and to determine the surface under the cumulative ranking curves (SUCRA) of the diagnostic value of different imaging methods for the detection of breast cancer in patients with PND. Additionally, a subgroup meta-analysis comparing ductoscopy to MRI when conventional imaging was negative was also performed. According to this NMA, sensitivity for detection of malignancy in patients with PND was highest for MRI (83%), followed by ductoscopy (58%), ultrasound (50%), cytology (38%), and mammogram (22%). Specificity was highest for mammogram (93%) followed by ductoscopy (92%), cytology (90%), MRI (76%), and ultrasound (69%). Diagnostic accuracy was the highest for ductoscopy (88%), followed by cytology (82%), MRI (77%), mammogram (76%), and ultrasound (65%). Subgroup meta-analysis (comparing ductoscopy to MRI when ultrasound and mammogram were negative) showed no significant difference in sensitivity, but ductoscopy was statistically significantly better with regard to specificity and diagnostic accuracy. The results from this NMA indicate that although ultrasound and mammogram may remain low-cost useful first choices for the detection of malignancy in patients with PND, ductoscopy outperforms most imaging techniques (especially MRI) and cytology.