A computer aided diagnosis system for lung nodules detection in postero anterior chest radiographs

This thesis describes a Computer Aided System aimed at lung nodules detection. The fully automatized method developed to search for nodules is composed by four steps. They are the segmentation of the lung field, the enhancement of the image, the extraction of the candidate regions, and the selection between them of the regions with the highest chance to be True Positives. The steps of segmentation, enhancement and candidates extraction are based on multi-scale analysis. The common assumption underlying their development is that the signal representing the details to be detected by each of them (lung borders or nodule regions) is composed by a mixture of more simple signals belonging to different scales and level of details. The last step of candidate region classification is the most complicate; its 8 task is to discern among a high number of candidate regions, the few True Positives. To this aim several features and different classifiers have been investigated. In Chapter 1 the segmentation algorithm is described; the algorithm has been tested on the images of two different databases, the JSRT and the Niguarda database, both described in the next section, for a total of 409 images. We compared the results obtained with another method presented in the literature and described by Ginneken, in [85], as the one obtaining the best performance at the state of the art; it has been tested on the same images of the JSRT database. No errors have been detected in the results obtained by our method, meanwhile the one previously mentioned produced an overall number of error equal to 50. Also the results obtained on the images of the Niguarda database confirmed the efficacy of the system realized, allowing us to say that this is the best method presented so far in the literature. This sentence is based also on the fact that this is the only system tested on such an amount of images, and they are belonging to two different databases. Chapter 2 is aimed at the description of the multi-scale enhancement and the extraction methods. The enhancement allows to produce an image where the \u201cconspicuity\u201d of nodules is increased, so that nodules of different sizes and located in parts of the lungs characterized by completely different anatomic noise are more visible. Based on the same assumption the candidates extraction procedure, described in the same chapter, employs a multi-scale method to detect all the nodules of different sizes. Also this step has been compared with two methods ([8] and [1]) described in the literature and tested on the same images. Our implementation of the first one of them ([8]) produced really poor results; the second one obtained a sensitivity ratio (See Appendix C for its definition) equal to 86%. The considerably better performance of our method is proved by the fact that the sensitivity ratio we obtained is much higher (it is equal to 97%) and also the number of False positives detected is much less. The experiments aimed at the classification of the candidates are described in chapter 3; both a rule based technique and 2 learning systems, the Multi Layer Perceptron (MLP) and the Support Vector Machine (SVM), have been investigated. Their input is a set of 16 features. The rule based system obtained the best performance: the cardinality of the set of candidates left is highly reduced without lowering the sensitivity of the system, since no True Positive region is lost. It can be added that this performance is much better than the one of the system used by Ginneken and Schilam in [1], since its sensitivity is lower (equal to 77%) and the number of False Positive left is comparable. The drawback of a rule based system is the need of setting the 9 thresholds used by the rules; since they are experimentally set the system is dependent on the images used to develop it. Therefore it may happen that, on different databases, the performance could not be so good. The result of the MLPs and of the SVMs are described in detail and the ROC analysis is also reported, regarding the experiments performed with the SVMs. Furthermore, the attempt to improve the performance of the classification leaded to other experiments employing SVMs trained with more complicate feature sets. The results obtained, since not better than the previous, showed the need of a proper selection of the features. Future works will then be focused at testing other sets of features, and their combination obtained by means of proper feature selection techniques

Bodies of Seeing: A video ethnography of academic x-ray image interpretation training and professional vision in undergraduate radiology and radiography education

This thesis reports on a UK-based video ethnography of academic x-ray image interpretation training across two undergraduate courses in radiology and radiography. By studying the teaching and learning practices of the classroom, I initially explore the professional vision of x-ray image interpretation and how its relation to normal radiographic anatomy founds the practice of being ‘critical’. This criticality accomplishes a faculty of perceptual norms that is coded and organised and also, therefore, of a specific radiological vision. Professionals’ commitment to the cognitivist rhetoric of ‘looking at’/‘pattern recognition’ builds this critical perception, a perception that deepens in organisation when professionals endorse a ‘systematic approach’ that mediates matter-of-fact thoroughness and offers a helpful critical commentary towards the image. In what follows, I explore how x-ray image interpretation is constituted in case presentations. During training, x-ray images are treated with suspicion and as misleading and are aligned with a commitment to discursive contexts of ‘missed abnormality’, ‘interpretive risk’, and ‘technical error’. The image is subsequently constructed as ambiguous and that what is shown cannot be taken at face value. This interconnects with reenacting ideals around ‘seeing clearly’ that are explained through the teaching practices and material world of the academic setting and how, if misinterpretation is established, the ambiguity of the image is reduced by embodied gestures and technoscientific knowledge. By making this correction, the ambiguous image is reenacted and the misinterpretation of image content is explained. To conclude, I highlight how the professional vision of academic x-ray image interpretation prepares students for the workplace, shapes the classificatory interpretation of ab(normal) anatomy, manages ambiguity through embodied expectations and bodily norms, and cultivates body-machine relations

Diseases of the Chest, Breast, Heart and Vessels 2019-2022

This open access book focuses on diagnostic and interventional imaging of the chest, breast, heart, and vessels. It consists of a remarkable collection of contributions authored by internationally respected experts, featuring the most recent diagnostic developments and technological advances with a highly didactical approach. The chapters are disease-oriented and cover all the relevant imaging modalities, including standard radiography, CT, nuclear medicine with PET, ultrasound and magnetic resonance imaging, as well as imaging-guided interventions. As such, it presents a comprehensive review of current knowledge on imaging of the heart and chest, as well as thoracic interventions and a selection of "hot topics". The book is intended for radiologists, however, it is also of interest to clinicians in oncology, cardiology, and pulmonology

Diseases of the Chest, Breast, Heart and Vessels 2019-2022

This open access book focuses on diagnostic and interventional imaging of the chest, breast, heart, and vessels. It consists of a remarkable collection of contributions authored by internationally respected experts, featuring the most recent diagnostic developments and technological advances with a highly didactical approach. The chapters are disease-oriented and cover all the relevant imaging modalities, including standard radiography, CT, nuclear medicine with PET, ultrasound and magnetic resonance imaging, as well as imaging-guided interventions. As such, it presents a comprehensive review of current knowledge on imaging of the heart and chest, as well as thoracic interventions and a selection of "hot topics". The book is intended for radiologists, however, it is also of interest to clinicians in oncology, cardiology, and pulmonology

Computer-aided diagnosis of tuberculosis in paediatric chest X-rays using local textural analysis

Includes abstract.Includes bibliographical references (leaves 99-103).This report presents a computerised tool to analyse the appearance of the lung fields in paediatric chest X-rays to detect the presence of tuberculosis. The computer aided diagnosis (CAD) tool consists of 4 phases: 1) lung field segmentation; 2) lung field subdivision; 3) feature extraction and 4) classification. Lung field segmentation is performed using a semi-automatic implementation of the active shape model algorithm. Two approaches to subdividing the lung fields into regions of interest are compared. The first divides each lung field into 21 overlapping regions of varying sizes, resulting in a total of 42 regions per image; this approach is called the big region approach. The second approach divides the lung fields into a large number of overlapping circular regions of interest. The circular regions have a radius of 32 pixels and are placed on an 8 x 8 pixel grid. This approach is called the circular region approach. Textural features are extracted from each of the regions using the moments of responses to a multiscale bank of Gaussian filters. Additional positional features are added to the circular regions

Primary carcinoma of the bronchus, with an investigation into its early x -ray diagnosis

#1. Carcinoma of the bronchus - by which is meant a bronchus of dimensions visible to the bronchoscopist - has a distinct clinical entity of its own, distinct from true lung tumors, with which it has previously been grouped. #2. Lung and bronchial tumors are moderately rare but are becoming more frequently diagnosed, and may be much more common than at present realized, owing to the frequency with which they are treated as tuberculosis. #3. A male preponderance and a right-sided maximum incidence seem to indicate a relationship to chronic irritation as an etiological but in the group of cases presented no ship could be established to tuberculosis, influenza, occupational diseases or over -smoking. #4. The clinical syndrome of the primary bronchial tumor is an absolutely persistent cough with either hemoptysis or scant but blood- stained sputum and the lesion is visible on bronchoscopy. The syndrome of primary parenchymal tumor, a much more latent lesion, is severe, otherwise unexplained, weight loss, associated with vague but constant chest pain, or dyspnoea, or the cough - blood combination of the bronchial group. #5. The two groups do not separate pathologically in the same manner. The gross pathology of parenchymal includes nodular, lobar and infiltrative forms, while the bronchial are all infiltrative. Microscopically we get all forms of adeno- carcinoma but also some squamous- celled carcinoma, and of the primary bronchial group reported six out of seven cases were of the latter type. This probably represents a metaplasia to an embryonic cell type latent in the development of the trachea and bronchi from the oesophageal bud. The growth tends to be of a highly malignant type. #6. The radiological literature describes a relatively late case. It groups the appearances as hilar or lober of which the hilar is the more frequent, but at the stage at which the lesion has been previously recognized secondary effects, stenosis, infection, pleural effusion or metastasis, usually complicate the picture. #7. The early diagnostic picture must be recognized in the routine films of the chest, and therefore a special technique is not called for, although stereoscopic films are of great assistance. #8. There are three characteristic factors suggestive of bronchial malignancy: (a) A hilar density, unilateral, occupying the whole hilus, usually just perceptibly separate from the mediastinum, rami- fying out into the parenchyma in irregular strand -like processes and unassociated with any other mediastinal deformity, occurs in the majority of cases. This -may be alone or be associated with one or other of the next two factors. (b) Atelectasis of a 1.hole or part of a lung without discoverable causal history, is very frequent. (c) A pseudo -bronchiectasis , an appearance radiologically identical with true bronchiectasis but caused by blood- filled bronchi. #9. Contrasting with this the parenchymal tumor is less dense, either roughly circular or lobar in shape, rather less infiltrative, and is seldom even apparently hilar in location. #10. This radiological picture of the early bronchial carcinoma must be distinguished from the following groups of lesions: (a) OTHER HILAR DENSITIES such as bronchitis, pneumonia, venous engorgement, will give a more diffuse infiltration and will always be bilateral. (b) APPARENT HILAR DENSITIES such as carcinoma of esophagus, aneurism, and such like, will show a certain definition of edge separating the lesion from the lung, even where there is apparent root infiltration. (c) TUBERCULOSIS will mostly give the features peculiar to that disease - an apical tendency, an irregular mottling rather than strand -like infiltration and an absence of hilar centering. (d) OTHER GLAND LESIONS have a definite edge and a crescentic shape rather than the projecting shape of the malignancy, and even if unilateral tend to show a general widening of the media - stinum. (e) INFLAMMATORY LESIONS are the most difficult as they are so protean in form but they have a general mottled nature, a tendency to multiplicity, an absence of hilar centering and a narrower limitation of the width of the infiltrating edge but never the smooth finished uninfiltrating edge of an stelectasis. #11. Although there are isolated reported cases of successful lobectomy for parenchymal carcinoma, nothing has yet been done for bronchial: but radium in the bronchus is suggested by the author

CT Scanning

Since its introduction in 1972, X-ray computed tomography (CT) has evolved into an essential diagnostic imaging tool for a continually increasing variety of clinical applications. The goal of this book was not simply to summarize currently available CT imaging techniques but also to provide clinical perspectives, advances in hybrid technologies, new applications other than medicine and an outlook on future developments. Major experts in this growing field contributed to this book, which is geared to radiologists, orthopedic surgeons, engineers, and clinical and basic researchers. We believe that CT scanning is an effective and essential tools in treatment planning, basic understanding of physiology, and and tackling the ever-increasing challenge of diagnosis in our society

Computer-aided diagnosis in chest radiography

Chest radiographs account for more than half of all radiological examinations; the chest is the mirror of health and disease. This thesis is about techniques for computer analysis of chest radiographs. It describes methods for texture analysis and segmenting the lung fields and rib cage in a chest film. It includes a description of an automatic system for detecting regions with abnormal texture, that is applied to a database of images from a tuberculosis screening program

Occupational respiratory diseases

Shipping list no.: 87-222-P."September 1986."S/N 017-033-00425-1 Item 499-F-2Also available via the World Wide Web.Includes bibliographies and index