Effects of Luminance and Resolution on Observer Performance with Chest Radiographs1

ArticleinRadiology 215(1):169-74 · April 2000with11 Reads
DOI: 10.1148/radiology.215.1.r00ap34169 · Source: PubMed
Abstract
To examine the combined effects of image resolution and display luminance on observer performance for detection of abnormalities depicted on posteroanterior chest radiographs. A total of 529 radiographs were displayed on a specially constructed view box at three luminance levels (770, 260, and 85 cd/m(2)) and three resolutions (100-microm, 200-microm, and 400-microm pixels). Each image was reviewed nine times by six radiologists who participated in this study. The abnormalities included nodule, pneumothorax, interstitial disease, alveolar infiltrates, and rib fracture. Negative (normal) radiographs were also included. Receiver operating characteristic curves indicated that the effect of image luminance was greater than that of resolution. The detection of pneumothorax, interstitial disease, and rib fracture showed statistically significant differences (P <. 05) due to luminance. The detection of pneumothorax was the only abnormality with a statistically significant difference due to resolution. There was no evidence that luminance was related to image resolution for any of the abnormalities. At a resolution of 400-microm pixels or higher across the field of view and a luminance of 260 cd/m(2) or more, primary diagnosis with posteroanterior chest radiographs is not likely to be affected by the quality of display.
    • "Imaging modalities require high-quality electronic display devices to convey precise and accurate information for diagnostic interpretation, clinical review, consultation or guidance during surgical procedures. Suboptimal or inconsistent performance of reading workstation monitors can prolong viewing times, increase reader fatigue, reduce detection of abnormalities and affect diagnostic performance12345. Good displays are of particular importance in the interpretation of mammograms where subtle malignancies demonstrate little grey level difference from normal breast tissues [6], and whilst much emphasis is placed on innovations that maximise pathology visualisation, the effectiveness of these developments rely on high-quality image presentation. "
    [Show abstract] [Hide abstract] ABSTRACT: This study measured reading workstation monitors and the viewing environment currently available within BreastScreen New South Wales (BSNSW) centres to determine levels of adherence to national and international guidelines. Thirteen workstations from four BSNSW service centres were assessed using the American Association of Physicists in Medicine Task Group 18 Quality Control test pattern. Reading workstation monitor performance and ambient light levels when interpreting screening mammographic images were assessed using spectroradiometer CS-2000 and chroma meter CL-200. Overall, radiologic monitors within BSNSW were operating at good acceptable levels. Some non-adherence to published guidelines included the percentage difference in maximum luminance between pairs of primary monitors at individual workstations (61.5 % or 30.8 % of workstations depending on specific guidelines), maximum luminance (23.1 % of workstations), luminance non-uniformity (11.5 % of workstations) and minimum luminance (3.8 % of workstations). A number of ambient light measurements did not comply with the only available evidence-based guideline relevant to the methodology used in this study. Larger ambient light variations across sites are shown when monitors were switched off, suggesting that differences in ambient lighting between sites can be masked when a standard mammogram is displayed for photometric measurements. Overall, BSNSW demonstrated good adherence to available guidelines, although some non-compliance has been shown. Recently updated United Kingdom and Australian guidelines should help reduce confusion generated by the plethora and sometimes dated nature of currently available recommendations.
    Full-text · Article · Jan 2013
    • "This might resulted in decreased discrimination of low contrast tissue such as mucosal shadows in the maxillary sinus. As the light stimuli from the low contrast mucosa is very faint to the human visual system, the decreased contrast sensitivity seems to cause deterioration in the radiological interpretation process.24 As Goo et al7 suggested that the observer performance was not affected under low ambient light, this study demonstrated that the detection performance might not be affected by an ambient light but was affected instead by a monitor luminance. "
    [Show abstract] [Hide abstract] ABSTRACT: The aim of this study was to evaluate the effect of liquid crystal display (LCD) monitor type and observer experience on the diagnostic performance in soft-copy interpretations of maxillary sinus inflammatory lesions on panoramic radiographs. Ninety maxillary sinuses on panoramic images were grouped into negative and positive groups according to the presence of inflammatory lesions, using CT for confirmation. Monochrome and color LCDs were used. Six observers participated and ROC analysis was performed to evaluate the diagnostic performance. The reading time, fatigue score, and inter-/intra-observer agreements were assessed. The interpretation of maxillary sinus inflammatory lesions was affected by the LCD monitor type used and by the experience of the observer. The reading time was not significantly different, however the fatigue score was significantly different between two LCD monitors. Inter-observer agreement was relatively good in experienced observers, while the intra-observer agreement for all observers was good with monochrome LCD but not with color LCD. The less experienced observers showed lowered diagnostic ability with a general color LCD.
    Full-text · Article · Mar 2011
    • "Although this study did not specifically address the influence of resolution, it may indicate that the resolution of a 2 megapixel monitor is adequate for primary diagnosis with posteroanterior chest images. This is in agreement with the studies of both Herron et al [7] and Otto et al [5], who observed that a resolution of 1 megapixel and a brightness of 260 cd m 22 should be sufficient for detecting nodules on chest images. Also Usami et al [9] found that an LCD monitor with a resolution higher than 1.3 megapixel can be sufficient for pulmonary nodule detection. "
    [Show abstract] [Hide abstract] ABSTRACT: The purpose of this study was to evaluate the influence of display quality on radiologists' performance in the detection of lung nodules. Display systems with various technical properties were considered based on their general availability in a radiology department. Their quality was assessed by physical tests. Multireader-multicase receiver operating characteristic (ROC) analysis was used to evaluate observer performance. The area under the curve (Az) was used as a metric for detectability of simulated lung nodules with diameters of 5 mm and 10 mm, and peak contrast values ranging from 0.1 (subtle) to 0.4 (evident) that were digitally superimposed on normal chest radiographs. Three experienced radiologists interpreted a batch of 60 radiographs on five different display systems; four monitors (two liquid crystal display (LCD) and two cathode ray tube (CRT) monitors) and one printed hardcopy. The physical tests showed superior performance of the two LCD monitors. ROC analysis resulted in the following Az scores: LCD-5MP Az = 0.78, hardcopy Az = 0.77, LCDc-2MP Az = 0.75, CRT-5MP Az = 0.72 and CRTc-1MP Az = 0.71. Difference in Az scores between the LCD-5MP monitor and both the CRT-5MP (p = 0.04) and CRTc-1MP (p = 0.01) monitors was significant. The primary class CRT-5MP monitor that showed reduced observer performance failed to comply with physical acceptance requirements. Luminance response was particularly observed to be insufficient. The results indicate that a quality assurance program has the potential to detect non-optimised display systems that could otherwise result in reduced observer performance.
    Full-text · Article · Oct 2007
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