Noninferiority and Equivalence Evaluation of Clinical Performance among Computed Radiography, Film, and Digitized Film for Telemammography Services.

Objective. The aim of this study was to evaluate and compare the clinical performance of different alternatives to implement low-cost screening telemammography. We compared computed radiography, film printed images, and digitized films produced with a specialized film digitizer and a digital camera. Material and Methods. The ethics committee of our institution approved this study. We assessed the equivalence of the clinical performance of observers for cancer detection. The factorial design included 70 screening patients, four technological alternatives, and cases interpreted by seven radiologists, for a total of 1,960 observations. The variables evaluated were the positive predictive value (PPV), accuracy, sensitivity, specificity, and the area under the receiver operating characteristic curves (AUC). Result. The mean values for the observed variables were as follows: accuracy ranged from 0.77 to 0.82, the PPV ranged from 0.67 to 0.68, sensitivity ranged from 0.64 to 0.74, specificity ranged from 0.87 to 0.90, and the AUC ranged from 0.87 to 0.90. At a difference of 0.1 to claim equivalence, all alternatives were equivalent for all variables. Conclusion. Our findings suggest that telemammography screening programs may be provided to underserved populations at a low cost, using a film digitizer or a digital camera.

DICOM gray-scale standard display function: clinical diagnostic accuracy of chest radiography in medical-grade gray-scale and consumer-grade color displays.

OBJECTIVE: The purpose of this study was to compare the diagnostic accuracy achieved with and without the calibration method established by the DICOM standard in both medical-grade gray-scale displays and consumer-grade color displays. MATERIALS AND METHODS: This study involved 76 cases, six radiologists, three displays, and two display calibrations for a total of 2736 observations in a multireader-multicase factorial design. The evaluated conditions were interstitial opacities, pneumothorax, and nodules. CT was adopted as the reference standard. One medical-grade gray-scale display and two consumer-grade color displays were evaluated. Analyses of ROC curves, diagnostic accuracy (measured as AUC), accuracy of condition classification, and false-positive and false-negative rate comparisons were performed. The degree of agreement between readers was also evaluated. RESULTS: No significant differences in image quality perception by the readers in the presence or absence of calibration were observed. Similar forms of the ROC curves were observed. No significant differences were detected in the observed variables (diagnostic accuracy, accuracy of condition classification, false-positive rates, false-negative rates, and image-quality perception). Strong agreement between readers was also determined for each display with and without calibration. CONCLUSION: For the chest conditions and selected observers included in this study, no significant differences were observed between the three evaluated displays with respect to accuracy performance with and without calibration.

Diagnostic accuracy of digitized chest X-rays using consumer-grade color displays for low-cost teleradiology services: a multireader-multicase comparison.

INTRODUCTION: In teleradiology services and in hospitals, the extensive use of visualization displays requires affordable devices. The purpose of this study was to compare three differently priced displays (a medical-grade grayscale display and two consumer-grade color displays) for image visualization of digitized chest X-rays. MATERIALS AND METHODS: The evaluated conditions were interstitial opacities, pneumothorax, and nodules using computed tomography as the gold standard. The comparison was accomplished in terms of receiver operating characteristic (ROC) curves, the diagnostic power measured as the area under ROC curves, accuracy in conditions classification, and main factors affecting accuracy, in a factorial study with 76 cases and six radiologists. RESULTS: The ROC curves for all of the displays and pathologies had similar shapes and no differences in diagnostic power. The proportion of cases correctly classified for each display was greater than 71.9%. The correctness proportions of the three displays were different (p<0.05) only for interstitial opacities. The evaluation of the main factors affecting these proportions revealed that the display factor was not significant for either nodule size or pneumothorax size (p>0.05). CONCLUSIONS: Although the image quality variables showed differences in the radiologists' perceptions of the image quality of the three displays, significant differences in the accuracy did not occur. The main effect on the variability of the proportions of correctly classified cases did not come from the display factor. This study confirms previous findings that medical-grade displays could be replaced by consumer-grade color displays with the same image quality.

Evaluation of three pneumothorax size quantification methods on digitized chest X-ray films using medical-grade grayscale and consumer-grade color displays.

This study focused on the effects of pneumothorax size quantification in digital radiology environments when a quantification method is selected according to the radiologist's criteria. The objective of this study was to assess the effects of factors, including the radiologist (with different experience), displays (medical-grade and consumer-grade displays), or display calibration, on the Rhea, Collins, and Light quantification methods. This study used a factorial design with 76 cases, including 16 pneumothorax cases observed by six radiologists on three displays with and without the DICOM standard calibration. The gold standard was established by two radiologists by using computed tomography. Analysis of variance (ANOVA) was performed on the pneumothorax sizes. For the three quantifications methods, none of the evaluated factors were significant. We conclude that radiologists, displays, and calibration do not significantly affect the quantification of pneumothorax size in different digital radiology environments.