| [Background and Objectives]With the development of picture archiving and communication system (PACS) and image post-processing and analysis technology, mainly computers and monitors to the "soft copy" reading mode, has been becoming increasingly popular, and gradually replace the "hard copy" reading mode. "Soft copy" means reading and greatly accelerated the diagnosis of image storage, transmission and diagnosis of the process of diagnostic imaging has become the development direction of the final section. However, the diagnosis of medical images used in professional displays of "soft copy" reading images, the diagnosis brought about by the impact of accuracy and reliability, the current assessment is still under study, but also a hot topic related fields.At present, Lots of research on using the Receiver Operating Characteristic (ROC) curve method to analysis digital images has been done abroad. There is also progress in the research of applying ROC curve domestically. Displaying and reading the minute structure in digital image, such as the small pulmonary nodules in chest image, is a key factor and a challenge in radiology research. Domestic and foreign scholars have been at different resolution displays for small lung nodules has made reading the impact of many useful and Research, has been generally accepted "soft reading" and "hard reading" with the same diagnostic performance, It's also believed that display with high resolution are much better than monitors with low resolution. Research on the basis of the above, the issue is the direction of the research diagnostic imaging①Through PACS workstation to application of different diagnostic imaging brands display (same resolution) on the chest Digital Radiography (DR) images on the accuracy of pulmonary nodule detection and the nature of nodules compared to evaluate the brand value between the display (diagnostic performance).②Studied at home and abroad, the display of the image diagnosis of pulmonary nodules based on the identification of all the different brands, different resolution, and a lot of comparative studies have been conducted in liquid crystal display (LCD) and cathode ray tube(CRT) display in comparison, the study to further standardize and monitor all the different brands of 3 million pixels (MP) of the LCD as a fundamental, based on the same platform, the reading of pulmonary nodules compared to compare their differences. And the application of ROC curves on display in 3MP diagnostic accuracy of pulmonary nodules on the preliminary study. The purpose is to further explore the different brands of medical diagnostic imaging and the need to monitor the feasibility of selection, to the medical unit of selection in the display to provide initial guidance to make rational use of hospital resources, with a reasonable display, to achieve a higher price.[Materials and Methods]1. The selected casesBy the two did not participate in this pilot study of senior-owned (> 15 years) doctors of diagnostic radiology from our search in March 2005-December 2008 in PACS database of the chest DR,and find or doubt nodules to CT screening examination, was found in a single CT diameter <30mm of nodules, and before two weeks to CT examination of chest examination was DR experts as positive; Also searched suspected chest nodules, and CT confirmed these nodules were not included in the negative group. According to nodule diameter,these cases were divided to 3 groups, 1～10mm group 24 cases and 10～30mm 40 cases; 26 cases of chest DR found but CT examining was not found as the negative group.2. Experimental equipment and methods Used three different brands of monitors ,Taiwan's CHILIN MDM2130-3NC (brand A), Japan EIZO RadiForce G31 (brand B), and the United States PLANAR Dome E3n (brand C), resolution of (1536×2048),they are all 20.8 inch monochrome screen erected Medical LCD; Five Diagnostic Radiology physicians at 3 brands of display separately on a second independent access to films, Each doctor can use the tools of the window width, level adjustment,enlarge and zoom access and the films room environmental control in the following 1201ux.3. Experimental oneThere are 90 cases of pulmonary nodules, using different brands 3MP monitors, diagnosed respectively by the five doctors (5 years 0.05, that brand A and C the difference was not between statistical significance. Thus, although the P value between brands vary, some with a significant difference, but in three separate brand names mean area under the curve can be drawn 0.891,0.901,0.892, are nearly equal to 0.9. So 3MP display s in the diagnosis diagnostic accuracy of pulmonary nodules is higher in general.3. The five doctors disscuss and unify the solitary pulmonary nodules of 10～30mm surrounding signs and symptoms, and the three brands with the display of two senior physician-owned diagnostic conclusions (as relative to gold standard) to carry out than the right. The results showed that the display of signs associated with peripheral nodular read with the significant difference between the standards, careful observation of each brand of solitary pulmonary nodules with signs reading, and carefully recorded data, Using kappa analysis (multi-class analysis of multi-evaluators) conformance testing, if in line with the rate, the K value is more close to 1, consistency as possible, consistent with the higher rate. The K value of brand B exceeds 0.40, K value of brand A and C exceeds 0.40. Classification from eight kinds of comparison, 3MP display for calcification, pleural tail sign and the empty cavity in line with the rate reached more than 0.8, it can be said that these signs with a high reading DR capability; As for the edge density, leaf and burr levy, in line with the three displays was significantly reduced, reaching a minimum 0.575. In summary, 3MP display nodular surrounding signs and symptoms for the low reading performance, the institute involved in the display, brand B in line with the overall rate and the K value slightly higher than the other two monitors, on brand B in the isolated peripheral pulmonary nodules with signs reading a little in regard to the other two brands. 4. Solitary pulmonary nodules based on the size, shape and perimeter with signs reading, the 10～30mm of pulmonary nodules as a preliminary diagnosis, the results with CT and pathology compared using kappa analysis, we have the nature of the nodules determine the context, brand A, B and C were consistent with the 0.35,0.475,0.4. The results showed, DR of solitary pulmonary nodules consistent with the low rate of diagnosis can only be good for the lung nodules, malignant tumors or tumor-like lesions in a preliminary screening. If necessary, when combined with clinical data and the need for further examination , the final diagnosis by CT and pathological.[Conclusion]1.In this study, the same resolution (3MP) in three types of display, the areas under the ROC curve Az are different. After statistical testing, the P values are different, but the reading of the pulmonary nodules, Whether a micro-nodules of < 10mm or 10～30mm of small nodules, the area under the curve is close to 0.9, solitary pulmonary nodule diagnosis of high performance on the 3MP LCD. Therefore, the diagnosis of high-resolution image display diagnostic radiology physicians can improve diagnostic accuracy and reduce false positives arising due to misdiagnosis, and to some extent to reduce individual differences in physician diagnosis of the impact.2.10～30mm for the perimeter of the nodules with the comparative study of signs, with review of the literature reported that the results show that, 3MP display for calcification, pleural tail sign and the hollow cavity of the reading in line with the rate has reached more than 0.8, it can be said that DR have a higher reading ability of these signs. For the edge density, leaf and burr levy, in line with the three displays were significantly reduced, reaching a minimum 0.575. Therefore, DR for signs of pulmonary nodule and characterization of lesions without high accuracy. Even with high-resolution display, or only for pulmonary nodule characterization of a preliminary determination.3.LCD as a result of medical professionals with ordinary LCD, CRT display piece for the soft reading room illumination requirements are different, there are differences in diagnostic performance.It is recommended as far as possible the professional choice of high-resolution LCD. But the medical profession the high cost of LCD and high brightness, long-term use cause eyestrain. Can be put into actual use in accordance with the capacity of hospitals and various departments, all departments in various positions on the image quality of the actual demand for a reasonable configuration. Such as breast mammography 5MP or 5MP image above requirements, CR and DR chest requirements 3MP, and CT, MR, DSA, the number of gastrointestinal request 2MP, image processing requirements of the Technical Group 2MP, related to display and can use character recognition 1MP color display. Reasonable configurations of the display of different resolution, to ensure that diagnostic accuracy will be better under the premise of cost-effective.4. For general radiodiagnoses department, it is definitely to combine the diagnosis workstation system with commercially available and professional monitors completely, the professional displays used for image reading and the commercially available displays mainly for general indicator of RIS reports and information enquirying. As different brands of medical professionals monitor the prices vary greatly, it is recommended to display cost-effective low-cost diagnostic workstation system configuration to achieve high diagnostic performance, and give full play to the advantages of digital imaging and effectively reduce costs and promote wider application of PACS.
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