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1.
Ergonomics ; : 1-12, 2024 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-38646862

RESUMO

Workplace incivility is considered a common workplace stressor, linked to a range of adverse impacts such as reduced wellbeing. However, there is a lack of research focused on how targets of incivility respond. The current study addresses that gap by examining responses to incivility within veterinary practice. Veterinarians and veterinary nurses (n = 132) evaluated six scenarios depicting two types of incivility (direct e.g. demeaning comments/indirect, for example, ignoring someone) across three instigators (clients, co-workers, senior colleagues), reporting their perception and appraisal of the uncivil behaviour depicted along with potential responses. Direct incivility was linked to responses such as reciprocation, exit, and support seeking, whereas indirect incivility was associated with affiliative and ignoring responses. Negative appraisal of incivility predicted a higher likelihood of exit, avoidance, support seeking and reporting responses. These findings suggest that incivility targets utilise a broad range of response options and adapt their response dependent on the situation.


This study investigated the influence of incivility type (direct/indirect) and instigator (client/co-worker/senior colleague) on response selection within veterinary practice. Participant responses were linked to incivility type and instigator status, indicating that utilisation of responses can be variable and adaptive to the situation.

2.
Eur Respir J ; 39(2): 344-51, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21737563

RESUMO

Hiatal hernia (HH) is associated with gastro-oesophageal reflux (GOR) and/or GOR disease and may contribute to idiopathic pulmonary fibrosis (IPF). We hypothesised that HH evaluated by computed tomography is more common in IPF than in asthma or chronic obstructive pulmonary disease (COPD), and correlates with abnormal GOR measured by pH probe testing. Rates of HH were compared in three cohorts, IPF (n=100), COPD (n=60) and asthma (n=24), and evaluated for inter-observer agreement. In IPF, symptoms and anti-reflux medications were correlated with diffusing capacity of the lung for carbon monoxide (D(L,CO)) and composite physiologic index (CPI). HH was correlated with pH probe testing in IPF patients (n=14). HH was higher in IPF (39%) than either COPD (13.3%, p=0.00009) or asthma (16.67%, p=0.0139). The HH inter-observer κ agreement was substantial in IPF (κ=0.78) and asthma (κ=0.86), and moderate in COPD (κ=0.42). In IPF, HH did not correlate with lung function, except in those on anti-reflux therapy, who had a better D(L,CO) (p<0.03) and CPI (p<0.04). HH correlated with GOR as measured by DeMeester scores (p<0.04). HH is more common in IPF than COPD or asthma. In an IPF cohort, HH correlated with higher DeMeester scores, confirming abnormal acid GOR. Presence of HH alone was not associated with decreased lung function.


Assuntos
Hérnia Hiatal/diagnóstico por imagem , Hérnia Hiatal/epidemiologia , Fibrose Pulmonar Idiopática/diagnóstico por imagem , Fibrose Pulmonar Idiopática/epidemiologia , Tomografia Computadorizada por Raios X/estatística & dados numéricos , Adulto , Idoso , Asma/diagnóstico por imagem , Asma/epidemiologia , Estudos de Coortes , Feminino , Refluxo Gastroesofágico/diagnóstico por imagem , Refluxo Gastroesofágico/epidemiologia , Refluxo Gastroesofágico/terapia , Humanos , Concentração de Íons de Hidrogênio , Doenças Pulmonares Intersticiais/diagnóstico por imagem , Doenças Pulmonares Intersticiais/epidemiologia , Masculino , Manometria , Pessoa de Meia-Idade , Variações Dependentes do Observador , Prevalência , Doença Pulmonar Obstrutiva Crônica/diagnóstico por imagem , Doença Pulmonar Obstrutiva Crônica/epidemiologia , Estudos Retrospectivos , Índice de Gravidade de Doença
3.
Arch Intern Med ; 143(12): 2323-4, 1983 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-6580844

RESUMO

A 37-year-old man with leukemia had the unusual complication of pulmonary aspergillosis eroding through adjacent bone. We were able to demonstrate this on computed tomography (CT) and even on the plain chest film. Bone invasion by an adjacent pulmonary lesion is most often attributed to other organisms or causes. This case demonstrates that aspergillosis must be added to the differential diagnosis of this finding. Recognizing this can be important for the prompt, appropriate treatment of opportunistic infections in the immunocompromised host.


Assuntos
Aspergilose/diagnóstico por imagem , Pneumopatias Fúngicas/diagnóstico por imagem , Adulto , Aspergilose/etiologia , Humanos , Leucemia Mieloide Aguda/complicações , Pneumopatias Fúngicas/etiologia , Masculino , Radiografia Torácica , Costelas/diagnóstico por imagem , Tomografia Computadorizada por Raios X
4.
Semin Oncol ; 10(1): 20-33, 1983 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-6340203

RESUMO

We feel that the guidelines described here reflect the state of the art at the time of writing (April 1982). The role of CT scanning is likely to evolve further and nuclear magnetic resonance (NMR) will probably play a significant role in the future. Experience, expertise, and equipment will vary from one hospital to another and thus rigid rules cannot reasonably be applied for the workup of suspected lung cancer. Ideally the diagnostic approach to an individual patient will be highly tailored, not only in regard to the nature of the pulmonary lesion, but also to his or her overall medical and social situation. We have found that a policy of early consultation between clinician and imaging specialist most readily facilitates effective use of available diagnostic resources.


Assuntos
Neoplasias Pulmonares/diagnóstico , Adulto , Biópsia , Biópsia por Agulha/efeitos adversos , Broncoscopia/efeitos adversos , Citodiagnóstico , Reações Falso-Negativas , Reações Falso-Positivas , Humanos , Neoplasias Pulmonares/diagnóstico por imagem , Mediastinoscopia , Toracoscopia , Tomografia , Tomografia Computadorizada por Raios X
5.
J Nucl Med ; 28(12): 1831-4, 1987 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-3681442

RESUMO

To determine the frequency, average duration, and characteristic patterns of persistent gallium uptake caused by thoracotomy, serial postsurgical scans of 51 patients were reviewed. In each of these cases a thoracotomy had been performed for resection of lung cancer, and there had been no evidence of recurrent tumor for at least 2 yr following surgery. Postoperative gallium activity due to non-neoplastic postoperative changes occurred in 15 patients. Five of six patients scanned within 3 mo of surgery and six of 21 scanned 3 to 6 mo following surgery showed persistent uptake at the operative site. All 13 patients who had subsequent scans demonstrated eventual clearing. Activity persisted more than 18 mo postoperatively in only one patient. Patterns of gallium accumulation included both focal chest wall uptake at the incision site and diffuse pleural activity.


Assuntos
Radioisótopos de Gálio , Toracotomia , Tórax/diagnóstico por imagem , Humanos , Período Pós-Operatório , Cintilografia
6.
Chest ; 95(1): 237-8, 1989 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-2909342

RESUMO

Recently, a new ECG lead has been introduced that can mimic a pulmonary nodule to the uninitiated. Alternatively, in those institutions where the lead is commonly seen, physicians may dismiss a real finding on the chest x-ray film as a lead "artifact." We describe the appearance of this new chest wall artifact.


Assuntos
Eletrocardiografia/instrumentação , Pulmão/diagnóstico por imagem , Nódulo Pulmonar Solitário/diagnóstico por imagem , Idoso , Erros de Diagnóstico , Feminino , Humanos , Radiografia
7.
Chest ; 77(5): 647-50, 1980 May.
Artigo em Inglês | MEDLINE | ID: mdl-7363683

RESUMO

In a 17-month period, 20 immunosuppressed patients underwent transbronchial biopsy of the lung for diagnostic evaluation of a pulmonary infiltrate of unknown etiology. In 19 patients, the transbronchial biopsy was nondiagnostic. Thirteen of the 19 patients were critically ill and were referred for an open lung biopsy. Eleven (85 percent) of these 13 patients left the hospital after open lung biopsy and appropriate medical treatment. Two patients who were receiving mechanical ventilation at the time of open biopsy succumbed to the combination of their underlying disease and respiratory failure. There were no deaths directly attributed to the open lung biopsy. Of the six patients whose condition appeared stable and who did not undergo open lung biopsy, two died from unrecognized progress of their underlying malignant disease. The remainder recovered. We conclude that open lung biopsy is safe in and beneficial to the diagnosis and subsequent treatment of unknown pulmonary infiltrates in immunosuppressed patients who previously had a nondiagnostic fiberoptic transbronchial biopsy of the lung.


Assuntos
Biópsia , Broncoscopia , Pneumopatias/patologia , Adulto , Idoso , Diagnóstico Diferencial , Feminino , Humanos , Síndromes de Imunodeficiência/patologia , Pulmão/patologia , Pneumopatias/terapia , Masculino , Pessoa de Meia-Idade , Respiração Artificial
8.
J Thorac Cardiovasc Surg ; 91(4): 498-504, 1986 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-3959567

RESUMO

To determine the regional accuracy of computed tomography of the mediastinum in staging lung cancer, we compared the results of preoperative computed tomographic staging to pathologic findings in lymph nodes taken at mediastinoscopy and/or thoracotomy in 61 patients. Twenty-two patients had adenocarcinoma, 24 had squamous cell carcinoma, eight had large cell tumors, and seven had small cell cancer or mixed cellular types. Sixteen patients had Stage I, eight had Stage II, and 37 had Stage III disease. Thirteen patients had mediastinoscopy only, and the remaining 48 patients had thoracotomy. Computed tomographic staging of the mediastinum as a whole had an accuracy of 88% with a negative predictive index of 96.1%. In examining the differential regional accuracy within the mediastinum we found results in the aortopulmonary window to be inferior to those of other regions, with an accuracy of 80% and a negative predictive index of 83.3%. The reliability of computed tomographic scan staging varied relative to cell type. The accuracy rate in adenocarcinoma was 94.7% compared to 70.6% in squamous cell carcinoma. Computed tomography is accurate for staging the mediastinum in lung cancer, and this accuracy holds over the regions of the mediastinum except the aortopulmonary window. Computed tomography is more accurate for staging adenocarcinoma than squamous cell cancer.


Assuntos
Adenocarcinoma/patologia , Carcinoma/patologia , Neoplasias Pulmonares/patologia , Mediastino/diagnóstico por imagem , Tomografia Computadorizada por Raios X , Adenocarcinoma/diagnóstico por imagem , Adulto , Idoso , Carcinoma/diagnóstico por imagem , Feminino , Humanos , Neoplasias Pulmonares/diagnóstico por imagem , Linfonodos/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade
9.
J Thorac Cardiovasc Surg ; 83(4): 551-62, 1982 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-6278231

RESUMO

Thirty-four patients with an aortic window lesion were carefully staged with gallium scans and mediastinoscopy according to the TNM classification system for carcinoma of the lung. All were in Stage III. Twenty-five patients had non-oat cell carcinomas (15 squamous cell, eight adeno-, two large cell) and nine had oat cell carcinomas. Quantitative ventilation-perfusion lung scans were particularly helpful in verifying the subaortic location of the tumor by showing a less than 20% interference with pulmonary blood flow or ventilation secondary to left mainstem bronchus or pulmonary artery invasion. Decision for resectability in 13 Stage III M0 patients was based on the length of the uninvolved proximal left main pulmonary artery seen on pulmonary arteriogram. Eight patients (seven non-oat cell and one oat cell) had resection after radiation and prior to chemotherapy (after two cycles of chemotherapy and prior to radiation therapy for the oat cell) with a resultant survival rate better than those of M0 and M1 non-oat cell or oat cell patients without resection. The survival rates of nine non-oat cell M0 patients, nine non-oat cell M1 patients, and eight oat cell patients, all without resection, were not statistically different. This similarity in survival rates is explained by the observation that 38% of the non-oat cell M1, 71% of the non-oat cell M0, and 63% of the oat cell patients died from complications of their primary tumor. Patients with aortic window lesions, irrespective of their histology, have an extremely poor prognosis due to the high incidence of lethal complications of their primary tumor. Complete resection when feasible, as judged by pulmonary arteriography, provides the best control of the primary tumor and, as a consequence, gives longer survival.


Assuntos
Carcinoma Broncogênico/mortalidade , Neoplasias Pulmonares/mortalidade , Adenocarcinoma/mortalidade , Adulto , Idoso , Aorta Torácica/diagnóstico por imagem , Carcinoma Broncogênico/tratamento farmacológico , Carcinoma Broncogênico/radioterapia , Carcinoma Broncogênico/cirurgia , Carcinoma de Células Pequenas/mortalidade , Carcinoma de Células Escamosas/mortalidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Artéria Pulmonar/diagnóstico por imagem , Radiografia , Relação Ventilação-Perfusão
10.
Invest Radiol ; 29(4): 459-65, 1994 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-8034453

RESUMO

RATIONALE AND OBJECTIVES: Interpretation of computed tomographic (CT) scans of the lungs is a time-consuming task that involves visual correlation of possible nodules in one section with those in contiguous sections to distinguish actual nodules from blood vessels. Thus, the authors are developing automated methods to detect nodules on CT images of the thorax. METHODS: The computerized technique uses various computer-vision techniques and a priori information of the morphologic characteristics of pulmonary nodules. In each section, the external thoracic wall and lung boundaries are detected, and the features within the lung boundaries are subjected to gray-level thresholding operations. By analyzing the relationships between features arising at different threshold levels with respect to their shape, size, and location, each feature is assigned a likelihood of being a nodule or a vessel. Features in adjacent sections are compared to resolve ambiguous features. Detected nodule candidates are displayed in three dimensions within the lung. RESULTS: The system provided a sensitivity of 94% for nodule detection and an average of 1.25 false-positive results per case. CONCLUSIONS: Continued development of an automated method for detecting pulmonary nodules in CT scans is expected to aid radiologists in the task of locating nodules in three dimensions.


Assuntos
Inteligência Artificial , Processamento de Imagem Assistida por Computador , Nódulo Pulmonar Solitário/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Reações Falso-Positivas , Humanos , Sensibilidade e Especificidade
11.
Invest Radiol ; 26(6): 546-50, 1991 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-1830564

RESUMO

Heart size is an important and useful diagnostic parameter in chest radiographs. However, there is a large variation in the subjective judgment of cardiac enlargement (cardiomegaly). To reduce this subjective element, the authors are developing an automated system for quantitative analysis of heart size in digital chest radiographs. Four hundred chest radiographs were reviewed initially by two radiologists and were classified into two groups: those with and those without cardiomegaly. Another radiologist reviewed 47 images which were not classified consistently in the initial review. The authors used these radiographs to construct a database for determination of cardiomegaly. Numerous parameters related to heart size were obtained in a semiautomated analysis of these radiographs, and the use of each parameter for detection of cardiomegaly was evaluated by means of receiver operating characteristic analysis. The authors also examined whether the accuracy would be improved when they applied multivariate analysis to a pair of parameters. From the analyses of the individual parameters, the automatically determined cardiothoracic ratio was found to be the single most effective measure for detecting cardiomegaly in chest radiographs. However, multivariate analysis provided results superior to those with an individual parameter.


Assuntos
Cardiomegalia/diagnóstico por imagem , Coração/diagnóstico por imagem , Intensificação de Imagem Radiográfica , Interpretação de Imagem Radiográfica Assistida por Computador , Radiografia Torácica , Humanos , Curva ROC
12.
Invest Radiol ; 25(6): 728-35, 1990 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-2191936

RESUMO

A method of evaluating pulmonary ventilation with a 57-cm image intensifier/television (II/TV) digital chest system is reported. With this method, the patient inhales a mixture of xenon and oxygen gases while dynamic imaging of the chest is done. Images of the airways and ventilated portions of the lungs are obtained by subtraction of images acquired before and after the xenon-oxygen mixture is administered. The feasibility of the method was evaluated by studies with xenon-filled tubes, an airway phantom, and a ventilation phantom. The results indicate that tubes larger than 3.2 mm in diameter are detectable at a xenon concentration of 41%, and that gas flow and flow distribution can be examined after image subtraction. If background subtraction is incomplete because of motion, the visibility of small airways is reduced greatly, although unventilated regions can still be delineated. The initial evaluation of this technique included imaging a healthy volunteer during xenon inhalation.


Assuntos
Meios de Contraste , Pulmão/diagnóstico por imagem , Intensificação de Imagem Radiográfica , Respiração , Xenônio , Humanos , Pulmão/fisiologia , Modelos Estruturais , Técnica de Subtração
13.
Invest Radiol ; 28(12): 1134-8, 1993 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-8307717

RESUMO

RATIONALE AND OBJECTIVES: Over- or underexposure often results in poor quality radiographs. Using receiver operating characteristic analysis, the authors investigated the potential utility of a system that corrects densities in such images to improve the accuracy of lung nodule detection. METHODS: Chest radiographs were digitized by a laser film digitizer. Simulated nodules were superimposed on 36 improperly exposed chest radiographs. All images, with and without nodules, were then processed by a nonlinear density-correction technique. Hard-copy images were produced by a laser film printer. Eight radiologists evaluated the corrected and uncorrected images for the presence or absence of lung nodules using a continuous (0-100) confidence-rating scale. RESULT: The detectability of lung nodules improved significantly in the retrocardiac/retrodiaphragmatic regions of underexposed images and in the peripheral lung region of overexposed images. CONCLUSIONS: This system may increase diagnostic accuracy in detection of lung nodules in improperly exposed images.


Assuntos
Intensificação de Imagem Radiográfica/instrumentação , Radiografia Torácica/instrumentação , Intervalos de Confiança , Estudos de Avaliação como Assunto , Reações Falso-Positivas , Humanos , Lasers , Neoplasias Pulmonares/diagnóstico por imagem , Neoplasias Pulmonares/epidemiologia , Modelos Estruturais , Variações Dependentes do Observador , Curva ROC , Radiografia Torácica/estatística & dados numéricos
14.
Invest Radiol ; 22(7): 581-9, 1987 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-3623862

RESUMO

We investigated the spatial resolution requirement and the effect of unsharp-mask filtering on the detectability of subtle microcalcifications in digital mammography. Digital images were obtained by digitizing conventional screen-film mammograms with a 0.1 X 0.1 mm2 pixel size, processed with unsharp masking, and then reconstituted on film with a Fuji image processing/simulation system (Fuji Photo Film Co., Tokyo, Japan). Twenty normal cases and 12 cases with subtle microcalcifications were included. Observer performance experiments were conducted to assess the detectability of subtle microcalcifications in the conventional, the unprocessed digital, and the unsharp-masked mammograms. The observer response data were evaluated using receiver operating characteristic (ROC) and LROC (ROC with localization) analyses. Our results indicate that digital mammograms obtained with 0.1 X 0.1 mm2 pixels provide lower detectability than the conventional screen-film mammograms. The detectability of microcalcifications in the digital mammograms is improved by unsharp-mask filtering; the processed mammograms still provide lower accuracy than the conventional mammograms, however, chiefly because of increased false-positive detection rates for the processed images at each subjective confidence level. Viewing unprocessed digital and unsharp-masked images in pairs resulted in approximately the same detectability as that obtained with the unsharp-masked images alone. However, this result may be influenced by the fact that the same limited viewing time was necessarily divided between the two images.


Assuntos
Neoplasias da Mama/diagnóstico por imagem , Calcinose/diagnóstico por imagem , Intensificação de Imagem Radiográfica , Reações Falso-Positivas , Feminino , Humanos , Mamografia/métodos , Estatística como Assunto
15.
Invest Radiol ; 27(6): 471-5, 1992 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-1607261

RESUMO

RATIONALE AND OBJECTIVE: To alert radiologists to possible nodule locations and subsequently to reduce the number of false-negative diagnoses, the authors are developing a computer-aided diagnostic (CAD) scheme for the detection of lung nodules in digital chest images. METHODS: A computer-vision scheme was applied to photofluorographic films obtained in a mass survey for detection of asymptomatic lung cancer in Japan. Ninety-five patients with abnormal test results who had primary and metastatic lung cancers and 103 patients with normal test results were included. RESULTS: The sensitivity of the computer output was comparable with that of physicians in this mass survey (62%). The computer detected approximately 40% of all nodules missed in the mass survey, but missed 17 true-positive results identified in the mass survey. The CAD scheme produced an average of 15 false-positive findings per image. CONCLUSION: If the number of false-positive results can be significantly reduced, computer-vision schemes such as this may have a role in lung cancer screening programs.


Assuntos
Radiografia Pulmonar de Massa , Interpretação de Imagem Radiográfica Assistida por Computador , Nódulo Pulmonar Solitário/prevenção & controle , Reações Falso-Positivas , Humanos , Japão/epidemiologia , Neoplasias Pulmonares/epidemiologia , Neoplasias Pulmonares/prevenção & controle , Intensificação de Imagem Radiográfica , Sensibilidade e Especificidade , Nódulo Pulmonar Solitário/epidemiologia
16.
Invest Radiol ; 27(2): 124-9, 1992 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-1601603

RESUMO

To aid radiologists in the detection of lung cancer, the authors are developing a computer-aided diagnosis system that locates areas suspicious for nodules in digital chest radiographs. The system involves a difference-image approach and various feature-extraction techniques. The authors describe nonlinear filters used in the difference-image approach. A morphological open operation and a ring-shaped median filter are applied in the difference-image step for signal enhancement and signal suppression, respectively. Using 60 clinical chest radiographs, the nonlinear filtering method detected approximately 63% of actual nodules with approximately 19 false-positive results per image. The locations of the false-positive detections, however, usually did not coincide with those from the linear filtering method. Thus, by using a combination of the detections from the two methods, the false-positive rate was reduced to two to three per image at a sensitivity of 60%.


Assuntos
Neoplasias Pulmonares/diagnóstico por imagem , Intensificação de Imagem Radiográfica/métodos , Tomografia Computadorizada por Raios X/métodos , Estudos de Avaliação como Assunto , Reações Falso-Positivas , Filtração/instrumentação , Filtração/métodos , Humanos , Pulmão/diagnóstico por imagem , Intensificação de Imagem Radiográfica/instrumentação , Tomografia Computadorizada por Raios X/instrumentação
17.
Invest Radiol ; 28(11): 987-93, 1993 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-8276583

RESUMO

RATIONALE AND OBJECTIVES: Computer-aided diagnosis (CAD) schemes for chest radiography are being developed with which to alert radiologists to possible lesions, and thus potentially improve diagnostic accuracy. However, CAD schemes have not been tested on a large number of clinical cases. The authors identify design parameters that would be required for development of an intelligent workstation. METHODS: Computer-aided diagnosis programs were applied for the automated detection of lung nodules, cardiomegaly, and interstitial infiltrates to 310 consecutive chest radiographs, and were analyzed for potential usefulness and limitations. Computer-aided diagnosis output was evaluated by radiologists and physicists for accuracy and technical problems, respectively. RESULTS: Approximately 70% of the results were judged to be potentially acceptable; however, the number of false-positive findings was relatively high. Technical problems included failure to detect subtle abnormalities and the occurrence of false-positive detections caused by normal anatomical structures. CONCLUSION: Computer-aided diagnosis has the potential to be a valuable aid to radiologists in clinical practice, if certain technical problems can be overcome and if optimal operating points can be defined for clinical use.


Assuntos
Interpretação de Imagem Radiográfica Assistida por Computador , Radiografia Torácica , Adulto , Cardiomegalia/diagnóstico por imagem , Erros de Diagnóstico , Humanos , Pneumopatias/diagnóstico por imagem
18.
Invest Radiol ; 22(4): 328-35, 1987 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-3583653

RESUMO

The basic imaging properties of a large (57 cm) image intensifier (I.I.)-TV digital imaging system were examined to determine the effects of various physical parameters on the quality of the digital chest images obtained, and also to explore the clinical usefulness of the system. The characteristic curve of the digital system, which relates the output pixel value to the input relative x-ray intensity, was measured with an aluminum stepwedge. MTFs were determined using slit images, and the veiling-glare fraction was measured with a lead-disk technique. Noise Wiener spectra were obtained from uniformly exposed images. The current limitations of the large II-TV digital chest system are its low spatial resolution, and the presence of large amounts of veiling glare and structure mottle. Advantages of this system over other digital chest imaging systems include the high speed of image data acquisition and the capability of "real-time" dynamic imaging of the chest at a radiation dose comparable to that in conventional radiography of the chest.


Assuntos
Intensificação de Imagem Radiográfica/instrumentação , Radiografia Torácica/instrumentação , Humanos
19.
Invest Radiol ; 27(8): 587-97, 1992 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-1428736

RESUMO

RATIONALE AND OBJECTIVES: To reduce the number of false-negative diagnoses by radiologists, the authors are developing a computer-aided diagnosis scheme for detection of lung nodules in digital chest images. In this study, the authors attempted to reduce the number of false-positive diagnoses obtained with a previous computer scheme by incorporating additional knowledge from experienced chest radiologists into the computer scheme. METHODS: The authors applied their previous computer scheme, using less-strict criteria, to 60 clinical chest radiographs; this yielded 735 candidate nodules (23 true nodules and 712 false-positive diagnoses). These candidates were analyzed using region-growing, trend-correction, and edge-gradient techniques to determine measures by which to quantify image features of candidate nodules. RESULTS: The 712 false-positive diagnoses represented various anatomic structures that were located throughout the chest image. From this analysis, we were able to decrease the number of false-positive errors from an average of 12 to approximately 5 per image without eliminating any true nodules. CONCLUSION: Our results show that incorporating knowledge from experienced chest radiologists into the computer algorithm will play an important role in the development of computerized schemes for the detection of pulmonary nodules.


Assuntos
Neoplasias Pulmonares/diagnóstico por imagem , Pulmão/diagnóstico por imagem , Interpretação de Imagem Radiográfica Assistida por Computador , Erros de Diagnóstico , Reações Falso-Positivas , Humanos , Pulmão/irrigação sanguínea , Intensificação de Imagem Radiográfica , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Costelas/diagnóstico por imagem
20.
Invest Radiol ; 25(10): 1102-10, 1990 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-2079409

RESUMO

Relatively simple, but important, detection tasks in radiology are nearing accessibility to computer-aided diagnostic (CAD) methods. The authors have studied one such task, the detection of clustered microcalcifications on mammograms, to determine whether CAD can improve radiologists' performance under controlled but generally realistic circumstances. The results of their receiver operating characteristic (ROC) study show that CAD, as implemented by their computer code in its present state of development, does significantly improve radiologists' accuracy in detecting clustered microcalcifications under conditions that simulate the rapid interpretation of screening mammograms. The results suggest also that a reduction in the computer's false-positive rate will further improve radiologists' diagnostic accuracy, although the improvement falls short of statistical significance in this study.


Assuntos
Calcinose/diagnóstico por imagem , Interpretação de Imagem Assistida por Computador , Mamografia/métodos , Feminino , Humanos , Mamografia/estatística & dados numéricos , Variações Dependentes do Observador , Curva ROC , Ecrans Intensificadores para Raios X
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