Antonio J. Salazar

Comparison Between Differently Priced Devices for Digital Capture of X-Ray Films Using Computed Tomography as a Gold Standard: A Multireader-Multicase Receiver Operating Characteristic Curve Study

OBJECTIVE Film digitizers are a specialized technology that is available for scanning X-ray radiographs; however, their cost makes them unaffordable for developing countries. Thus, less expensive alternatives are used. The purpose of this study was to compare three devices for digital capture of X-ray films: a film digitizer (US

DICOM Gray-Scale Standard Display Function: Clinical Diagnostic Accuracy of Chest Radiography in Medical-Grade Gray-Scale and Consumer-Grade Color Displays

15,000), a flatbed scanner (US

Evaluation of Three Pneumothorax Size Quantification Methods on Digitized Chest X-ray Films Using Medical-Grade Grayscale and Consumer-Grade Color Displays

1800), and a 10-megapixel digital camera (US

Agreement and reading time for differently-priced devices for the digital capture of X-ray films.

450), in terms of diagnostic accuracy, defined as the area under the receiver operating characteristic curves and computed tomography as the gold standard. MATERIALS AND METHODS The sample included 136 chest X-ray cases with computed tomography confirmation of the presence or absence of pneumothorax, interstitial opacities, or nodules. The readers were six radiologists who made observations of eight variables for each digital capture of the X-ray films: three main variables to determine the accuracy in the detection of the above-mentioned pathologies, four secondary variables to categorize other pathological classifications, and one variable regarding digital image quality. RESULTS The receiver operating characteristic curves for each device and pathology were very similar. For the main variables, there was no significant statistical difference in diagnostic accuracy between the devices. For the secondary variables, >84% of cases were correctly classified, even those that were classified with the lowest image quality. High accuracy was determined for the three main variables (0.75 to 0.96), indicating good performance for all tested devices, despite their very different prices. CONCLUSIONS Choosing a device for a teleradiology service should involve additional factors, such as capture time, maintenance concerns, and training requirements.

Evaluation of Low-Cost Telemammography Screening Configurations: A Comparison with Film-Screen Readings in Vulnerable Areas

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.

Effects of the DICOM grayscale standard display function on the accuracy of medical-grade grayscale and consumer-grade color displays for telemammography screening

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.

Ruling Out Brain CT Contraindications prior to Intravenous Thrombolysis: Diagnostic Equivalence between a Primary Interpretation Workstation and a Mobile Tablet Computer

We assessed the reliability of three digital capture devices: a film digitizer (which cost US

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

15,000), a flat-bed scanner (US

Comparison between Different Cost Devices for Digital Capture of X-ray Films: An Image Characteristics Detection Approach

1800) and a digital camera (US

Diagnostic Accuracy of Digitized Chest X-Rays Using Consumer-Grade Color Displays for Low-Cost Teleradiology Services: A Multireader–Multicase Comparison

450). Reliability was measured as the agreement between six observers when reading images acquired from a single device and also in terms of the pair-device agreement. The images were 136 chest X-ray cases. The variables measured were the interstitial opacities distribution, interstitial patterns, nodule size and percentage pneumothorax size. The agreement between the six readers when reading images acquired from a single device was similar for the three devices. The pair-device agreements were moderate for all variables. There were significant differences in reading-time between devices: the mean reading-time for the film digitizer was 93 s, it was 59 s for the flat-bed scanner and 70 s for the digital camera. Despite the differences in their cost, there were no substantial differences in the performance of the three devices.