Using breast radiographers\u27 reports as a second opinion for radiologists\u27 readings of microcalcifications in digital mammography

Objective: The aim of this study was to investigate a practical method for incorporating radiographers\u27 reports with radiologists\u27 readings of digital mammograms. Methods: This simulation study was conducted using data from a free-response receiver operating characteristic observer study obtained with 75 cases (25 malignant, 25 benign and 25 normal cases) of digital mammograms. Each of the rating scores obtained by six breast radiographers was utilized as a second opinion for four radiologists\u27 readings with the radiographers\u27 reports. A logical "OR" operation with various criteria settings was simulated for deciding an appropriate method to select a radiographer\u27s report in all combinations of radiologists and radiographers. The average figure of merit (FOM) of the radiologists\u27 performances was statistically analysed using a jackknife procedure (JAFROC) to verify the clinical utility of using radiographers\u27 reports. Results: Potential improvement of the average FOM of the radiologists\u27 performances for identifying malignant microcalcifications could be expected when using radiographers\u27 reports as a second opinion. When the threshold value of 2.6 in Breast Imaging-Reporting and Data System (BI-RADS®) assessment was applied to adopt/ reject a radiographer\u27s report, FOMs of radiologists\u27 performances were further improved. Conclusion: When using breast radiographers\u27 reports as a second opinion, radiologists\u27 performances potentially improved when reading digital mammograms. It could be anticipated that radiologists\u27 performances were improved further by setting a threshold value on the BIRADS assessment provided by the radiographers. Advances in knowledge: For the effective use of a radiographer\u27s report as a second opinion, radiographers\u27 rating scores and its criteria setting for adoption/ rejection would be necessary

Eigenspace Template Matching for Detection of Lacunar Infarcts on MR Images

Abstract Detection of lacunar infarcts is important because their presence indicates an increased risk of severe cerebral infarction. However, accurate identification is often hindered by the difficulty in distinguishing between lacunar infarcts and enlarged Virchow-Robin spaces. Therefore, we developed a computer-aided detection (CAD) scheme for the detection of lacunar infarcts. Although our previous CAD method indicated a sensitivity of 96.8 % with 0.71 false positives (FPs) per slice, further reduction of FPs remained an issue for the clinical application. Thus, the purpose of this study is to improve our CAD scheme by using template matching in the eigenspace. Conventional template matching is useful for the reduction of FPs, but it has the following two pitfalls: (1) It needs to maintain a large number of templates to improve the detection performance, and (2) calculation of the crosscorrelation coefficient with these templates is time consuming. To solve these problems, we used template matching in the lower dimension space made by a principal component analysis. Our database comprised 1,143 T 1 -and T 2 -weighted images obtained from 132 patients. The proposed method was evaluated by using twofold cross-validation. By using this method, 34.1 % of FPs was eliminated compared with our previous method. The final performance indicated that the sensitivity of the detection of lacunar infarcts was 96.8 % with 0.47 FPs per slice. Therefore, the modified CAD scheme could improve FP rate without a significant reduction in the true positive rate

Usefulness of presentation of similar images in the diagnosis of breast masses on mammograms: comparison of observer performances in Japan and the USA

Abstract Computer-aided diagnosis has potential in improving radiologists' diagnosis, and presentation of similar images as a reference may provide additional useful information for distinction between benign and malignant lesions. In this study, we evaluated the usefulness of presentation of reference images in observer performance studies and compared the results obtained by groups of observers practicing in the United States and Japan. The results showed that the presentation of the reference images was generally effective for both groups, as the areas under the receiver operating characteristic curves improved from 0.915 to 0.924 for the group in the US and from 0.913 to 0.925 for the group in Japan, although the differences were marginally (p = 0.047) and not (p = 0.13) statistically significant, respectively. There was a slight difference between the two groups in the way that the observers reacted to some benign cases, which might be due to differences in the population of screenees and in the socioclinical environment. In the future, it may be worthwhile to investigate the development of a customized system for physicians in different socio-clinical environments

チホウ ブンケン ト ノウソン ザイセイ コウゾウ ノ コウサツ : ノウセイ ヘンヨウ カテイ ニ オケル チョウソン ジチタイ タンドク ジギョウ ノ ザイセイ モンダイ ト ノ カンレン デ

平成11年に「地方分権法」が施行され,奨励的補助金の新設が中止された。その結果,食料・農業・農村基本法の最重要施策である「中山間地域等直接支払」制度に対して農林水産省は補助金が仕組めず,交付金で措置することになった。交付金は補助金より国の主体性が弱く,政策としては大きく後退し,自治体への依存が高まっている。以上の問題意識から,本論文は「地方分権法」と農村財政構造につて,農政変容過程における町村自治体単独事業の財源問題との関連に焦点を当て考察している。具体的には,第1に,すでに1兆円に達している自治省の農山漁村対策事業費の実態を解明している。第2に,国の施策の受皿となる自治体,とくに,農村地域に大部分が立地する町村の財政力構造を考察している。第3に 財政力が脆弱な町村自治体に対する財源対策への提言を行なっている。Firstly, the aim of analysis is to clarify the actual condition of the finance for development project in the rural, mountainous and fishery areas, on which is expended a trillion Yen per year through the Ministry of Home Affairs. Secondly, the aim is to clarify the finance ability of the local government, mainly the government of towns and villages which applies the policy of the central government. Lastly, the aim is to propose a new vision for the finance policy of government of towns and villages in which the financial ability is very weak. In 1999, the government introduced the law of decentralization of power, and encouraged subsidies to be stopped. For that reason, the Ministry of Agriculture, Forestry and Fishery is obliged to introduce not subsidies, but local allocation taxes which were used as a direct payment system for farmers in the less favorable rural-mountainous area, a most important policy in the Food, Agricultural and Rural Basic Law

A computerized scheme for lung nodule detection in multiprojection chest radiography: Lung nodule detection in multiprojection chest radiography

Purpose: Our previous study indicated that multiprojection chest radiography could significantly improve radiologists’ performance for lung nodule detection in clinical practice. In this study, the authors further verify that multiprojection chest radiography can greatly improve the performance of a computer-aided diagnostic (CAD) scheme

Lungs cancer nodules detection from ct scan images with convolutional neural networks

Lungs cancer is a life-taking disease and is causing a problem around the world for a long time. The only plausible solution for this type of disease is the early detection of the disease because at preliminary stages it can be treated or cured. With the recent medical advancements, Computerized Tomography (CT) scan is the best technique out there to get the images of internal body organs. Sometimes, even experienced doctors are not able to identify cancer just by looking at the CT scan. During the past few years, a lot of research work is devoted to achieve the task for lung cancer detection but they failed to achieve accuracy. The main objective of this piece of this research was to find an appropriate method for classification of nodules and non-nodules. For classification, the dataset was taken from Japanese Society of Radiological Technology (JSRT) with 247 three-dimensional images. The images were preprocessed into gray-scale images. The lung cancer detection model was built using Convolutional Neural Networks (CNN). The model was able to achieve an accuracy of 88% with lowest loss rate of 0.21% and was found better than other highly complex methods for classification