Diagnostic performance in differentiation of breast lesion on digital mammograms: comparison among hard-copy film, 3-megapixel LCD monitor, and 5-megapixel LCD monitor

We compared observer performance of digital mammography among hard-copy readings and soft-copy readings using 3-megapixel (3M) and 5-megapixel (5M) liquid crystal display (LCD) monitors. Five experienced radiologists assessed 80 mammograms of 40 cancers and 40 benign lesions. There were no significant differences among the average A_z of three modalities and among the κ values for intra- and interobserver agreement. The soft-copy reading using the 3M LCD monitor took a slightly longer time, although there were no significant differences.     

Comparison of observer performance on soft-copy reading of digital chest radiographs: high resolution liquid-crystal display monitors versus cathode-ray tube monitors

The purpose of this study is to compare observer performance for detection of abnormalities on chest radiographs with 5-megapixel resolution liquid-crystal displays (LCD) and 5-megapixel resolution cathode-ray tube (CRT) monitors under bright and subdued ambient light conditions. Six radiologists reviewed a total of 254 digital chest radiographs under four different conditions with a combination of two types of monitors (a 5-megapixel resolution LCD and a 5-megapixel resolution CRT monitor) and with two types of ambient light (460 and 50 lux). The abnormalities analyzed were nodules, pneumothorax and interstitial lung disease. For each reader, the detection performance using 5-megapixel LCD and 5-megapixel CRT monitors under bright and subdued ambient light conditions were compared using multi-case and multi-modality ROC analysis. For each type of ambient light, the average detection performance with the two types of monitors was also compared. For each reader, the observer performance of 5-megapixel LCD and 5-megapixel CRT monitors, under both bright and subdued ambient light conditions, showed no significant statistical differences for detecting nodules, pneumothorax and interstitial lung disease. In addition, there was no significant statistical difference in the average performance when the two monitor displays, under both bright and subdued ambient light conditions, were compared.     

Diagnostic performance of detecting breast cancer on computed radiographic (CR) mammograms: comparison of hard copy film, 3-megapixel liquid-crystal-display (LCD) monitor and 5-megapixel LCD monitor

The purpose was to compare observer performance in the detection of breast cancer using hard-copy film, and 3-megapixel (3-MP) and 5-megapixel (5-MP) liquid crystal display (LCD) monitors in a simulated screening setting. We amassed 100 sample sets, including 32 patients with surgically proven breast cancer (masses present, N = 12; microcalcifications, N = 10; other types, N = 10) and 68 normal controls. All the mammograms were obtained using computed radiography (CR; sampling pitch of 50 μm). Twelve mammographers independently assessed CR mammograms presented in random order for hard-copy and soft-copy reading at minimal 4-week intervals. Observers rated the images on seven-point (1 to 7) and continuous (0 to 100) malignancy scales. Receiver-operating-characteristics analysis was performed, and the average area under the curve (AUC) was calculated for each modality. The jackknife method with the Bonferroni correction was applied to multireader/multicase analysis. The average AUC values for the 3-MP LCD, 5-MP LCD, and hard-copy film were 0.954, 0.947, and 0.956 on the seven-point scale and 0.943, 0.923, and 0.944 on the continuous scale, respectively. There were no significant differences among the three modalities on either scale. Soft-copy reading using 3-MP and 5-MP LCDs is comparable to hard-copy reading for detecting breast cancer.     

The influence of liquid crystal display (LCD) monitors on observer performance for the detection of nodular lesions on chest radiographs

Purpose To access the influence of liquid crystal display (LCD) monitors on the detectability of nodular lesions depicted on chest radiographs by comparing them with a high-resolution cathode ray tube (CRT) monitor. Material and methods Ten radiologists interpreted 247 soft-copy images on LCD monitors with pixel arrays of 1,024×1,280, 1,200×1,600, 1,536×2,048 and 2,048×2,560, and a CRT monitor with a pixel array of 2,048×2,560, and were asked to indicate their individual confidence levels regarding the presence of a nodule. These images were chest radiographs with and without a lung nodule from the “Standard Digital Image Database” created by the Japanese Society of Radiological Technology. The luminance distributions of all monitors were adjusted to the same, and the ambient illumination was 200 lux. Observer performance was analyzed in terms of the receiver-operating characteristics. Results No significant statistical differences in nodule detection performance were found among the four LCD monitors and the CRT monitor. Conclusion The nodule detection performance on the LCD monitors with a spatial resolution higher than a matrix size of 1,024×1,280 was found to be equivalent to that on the high-resolution CRT monitor.     

The influence of liquid crystal display monitors on observer performance for the detection of interstitial lung markings on both storage phosphor and flat-panel-detector chest radiography

Purpose

To compare observer performance with a flat-panel liquid crystal display (LCD) monitor and with a high-resolution gray-scale cathode ray tube (CRT) monitor in the detection of interstitial lung markings using a silicon flat-panel-detector direct radiography (DR) and storage phosphor computed radiography (CR) in a clinical setting.

Materials and methods

We displayed 39 sets of posteroanterior chest radiographs from the patients who were suspected of interstitial lung disease. Each sets consisted of DR, CR and thin-section CT as the reference standard. Image identities were masked, randomly sorted, and displayed on both five mega pixel (2048 × 2560 × 8 bits) LCD and CRT monitors. Ten radiologists independently rated their confidence in detection for the presence of linear opacities in the four fields of the lungs; right upper, left upper, right lower, and left lower quadrant. Performance of a total 6240 (39 sets × 2 detector systems × 2 monitor system × 4 fields × 10 observers) observations was analyzed by multi-reader multi-case receiver operating characteristic (ROC) analysis. Differences between monitor systems in combinations of detector systems were compared using ANOVA and paired-samples t-test.

Results

Area under curves (AUC) for the presence of linear opacities measured by ROC analysis was higher on the LCDs than CRTs without statistical significance (p = 0.082). AUC was significantly higher on the DR systems than CR systems (p = 0.006). AUC was significantly higher on the LCDs than CRTs for DR systems (p = 0.039) but not different for CR systems (p = 0.301).

Conclusion

In clinical conditions, performance of the LCD monitor appears to be better for detecting interstitial lung markings when interfaced with DR systems.     

Influence of liquid crystal display monitors on observer performance for detection of diffuse pulmonary disease on chest radiographs

Purpose The purpose of this study was to assess the influence of liquid crystal display (LCD) monitors on the detectability of diffuse pulmonary diseases depicted on chest radiographs by comparing them with a high-resolution cathode ray tube (CRT) monitor. Materials and methods A group of 17 radiologists interpreted 87 soft-copy images on LCD monitors with pixel arrays of 1024 × 1280, 1200 × 1600, 1536 × 2048, and 2048 × 2560 and on a CRT monitor with a pixel array of 2048 × 2560. They were asked to indicate their individual confidence levels regarding the presence of diffuse pulmonary diseases. The luminance distributions of all monitors were adjusted to the same distributions, and the ambient illumination was 200 lux. Observer performance was analyzed in terms of the receiver operating characteristics (ROC). Results The average ROC curves for the five monitor types were similar, and there were no statistically reliable effects of the five monitor types on the readers’ diagnostic performances (P = 0.7587). Conclusion The detectability of diffuse pulmonary disease on the LCD monitors with a spatial resolution equal to or higher than a matrix size of 1024 × 1280 was found to be equivalent to that on the high-resolution CRT monitor.     

Detection of masses and clustered microcalcifications on data compressed mammograms: an observer performance study

OBJECTIVE: To evaluate observers' ability to detect breast masses and clustered microcalcifications depicted on data compressed mammograms, an observer performance study was performed. MATERIALS AND METHODS: Eight observers assessed 60 mammographic images obtained in six modes, ranging from noncompressed to a maximum data compression level of 101:1. Observers were asked to rate the images on a scale of 0 to 100 for the likelihood of the presence of a mass and also independently for the likelihood of the presence of clustered microcalcifications. In addition, observers were asked to rate their subjective assessment of the quality of each image for the detection of a mass and separately for the detection of microcalcifications. Receiver operating characteristic analyses were performed. RESULTS: The average area under the receiver operating characteristic curve, A(z), for the detection of clustered microcalcifications decreases significantly at the highest data compression level when compared with the noncompressed and two lowest levels of data compression (p < 0.01), and a trend test of the average area under the receiver operating characteristic curve for all observers is statistically significant (p < 0.05). No statistically significant differences among or between any of the data compression level modes for the detection of masses were detected. CONCLUSION: At a high level of mammogram data compression, observer performance was degraded for the detection of clustered microcalcifications. Detection of masses was not affected by the data compression methods and levels used in this study.     

炎性乳癌和急性乳腺炎MR成像：对比研究

该研究目的是评估MR乳腺成像鉴别炎性乳癌和急性乳腺炎的潜力。该研究比较了2组经过选择的病人的MR乳腺成像检查：48例炎性乳癌和42例急性乳腺炎。2组之间在以下方面未显示显著性差异：肿块形态，非肿块样增强形态，乳腺增大，弥漫性皮肤增厚，异常乳头外形，凸出的血管，皮肤／皮下的、乳头旁和弥漫性水肿。     

Use of prior mammograms in the transition to digital mammography: a performance and cost analysis

Breast screening in Europe is gradually changing from film to digital imaging and reporting of cases. In the transition period prior mammograms (from the preceding screening round) are films thereby potentially causing difficulties in comparison to current digital mammograms. To examine this breast screening performance was measured at a digital mammography workstation with prior mammograms displayed in different formats, and the associated costs calculated. 160 selected difficult cases (41% malignant) were read by eight UK qualified mammography readers in three conditions: with film prior mammograms; with digitised prior mammograms; or without prior mammograms. Lesion location and probability of malignancy were recorded, alongside a decision of whether to recall each case for further tests. JAFROC analysis showed a difference between conditions (p=.006); performance with prior mammograms in either film or digitised formats was superior to that without prior mammograms (p<.05). There was no difference in the performance when the prior mammograms were presented in film or digitised form. The number of benign or normal cases recalled was 26% higher without prior mammograms than with digitised or film prior mammograms (p<.05). This would correspond to an increase in recall rate at the study hospital from 4.3% to 5.5% with no associated increase in cancer detection rate. The cost of this increase was estimated to be ￡11,581 (€13,666) per 10,000 women screened, which is higher than the cost of digitised (￡11,114/€13,115), or film display (￡6451/€7612) of the prior mammograms. It is recommended that, where available, prior mammograms are used in the transition to digital breast screening.     

Soft-copy reading in digital mammography of microcalcifications: diagnostic performance of a 5-megapixel cathode ray tube monitor versus a 3-megapixel liquid crystal display monitor in a clinical setting

BACKGROUND: A recent study using dedicated contrast-detail phantoms showed that the image quality of a 3-megapixel (M) monitor can approach that of a 5M monitor in digital mammography. PURPOSE: To compare a 5M cathode ray tube (CRT) monitor with a 3M liquid crystal display (LCD) monitor for soft-copy reading of digital mammography of microcalcifications in a clinical setting. MATERIAL AND METHODS: 100 screen-detected microcalcification lesions (34 malignant and 66 benign) without mass that had been evaluated with 11-gauge stereotactic vacuum-assisted breast biopsy or definitive surgery were recruited into the study. One radiologist analyzed the soft-copy mammograms on a 5M CRT monitor and a 3M LCD monitor with 5 months between interpretations and scored the likelihood of malignancy and calcification distribution on a five-point scale. Calcification morphology and breast density were scored on a four-point scale. Positive predictive value (PPV) and negative predictive value (NPV) were calculated on the basis of a Breast Imaging Reporting and Data System. The interpretation time was also measured. RESULTS: There was no significant difference in the likelihood of malignancy (P = 0.655), calcification morphology (P = 0.168), calcification distribution (P = 0.11), and breast density (P = 0.0608). The PPV and NPV of soft-copy reading on the 5M CRT monitor was 57% (30/53) and 91% (43/47), respectively, identical to the results using the 3M LCD monitor. The total interpretation time averaged 88 s for the 5M CRT monitor and 67 s for the 3M LCD monitor (P<0.0001). CONCLUSION: Soft-copy reading of a digital mammography of microcalcifications with a 3M LCD monitor was similar in diagnostic performance to a 5M CRT monitor in this study.     

Interobserver agreement and performance score comparison in quality control using a breast phantom: screen-film mammography vs computed radiography

Our objective was to evaluate interobserver agreement and to compare the performance score in quality control of screen-film mammography and computed radiography (CR) using a breast phantom. Eleven radiologists interpreted a breast phantom image (CIRS model X) by four viewing methods: (a) original screen-film; (b) soft-copy reading of the digitized film image; (c) hard-copy reading of CR using an imaging plate; and (d) soft-copy reading of CR. For the soft-copy reading, a 17-in. CRT monitor (1024x1536x8 bits) was used. The phantom image was evaluated using a scoring system outlined in the instruction manual, and observers judged each object using a three-point rating scale: (a) clearly seen; (b) barely seen; and (c) not seen. For statistical analysis, the kappa statistic was employed. For "mass" depiction, interobserver agreement using CR was significantly lower than when using screen-film ( p<0.05). There was no significant difference in the kappa value for detecting "microcalcification"; however, the performance score of "microcalcification" on CR hard-copy was significantly lower than on the other three viewing methods ( p<0.05). Viewing methods (film or CR, soft-copy or hard-copy) could affect how the phantom image is judged. Paying special attention to viewing conditions is recommended for quality control of CR mammograms.