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1.  Imaging Informatics: Challenges in Multi-site Imaging Trials 
Journal of Digital Imaging  2010;24(1):151-159.
Multi-site imaging research has several specialized needs that are substantially different from what is commonly available in clinical imaging systems. An attempt to address these concerns is being led by several institutes including the National Institutes of Health and the National Cancer Institute. With the exception of results reporting (which has an infrastructure for standard reports, albeit with several competing lexicons), medical imaging has been largely standardized by the efforts of DICOM, HL7, and IHE. What are not well developed in this area are the tools required for multi-site imaging collaboration and data mining. The goal of this paper is to identify existing clinical interoperability methods that can be used to harmonize the research and clinical worlds, and identify gaps where they exist. To do so, we will detail the approaches of a specific multi-site trial, point out the current deficiencies and workarounds developed in that trial, and finally point to work that seeks to address multi-site imaging challenges.
PMCID: PMC3046789  PMID: 20306113
Clinical information systems; clinical trial; controlled vocabulary
2.  ROC Study of Four LCD Displays Under Typical Medical Center Lighting Conditions 
Journal of Digital Imaging  2006;19(1):30-40.
Nine observers reviewed a previously assembled library of 320 chest computed radiography (CR) images. Observers participated in four sessions, reading a different 1/4 of the sample on each of four liquid crystal displays: a 2-megapixel (MP) consumer color display, a 2-MP business color display, a 2-MP medical-grade gray display, and a 3-MP gray display. Each display was calibrated according to the DICOM Part 14 standard. The viewing application required observer login, then randomized the order of the subsample seen on the display, and timed the responses of the observer to render a 1–5 judgment on the absence or presence of ILD on chest CRs. Selections of 1–2 were considered negative, 3 was indeterminate, and 4–5 were positive. The order of viewing sessions was also randomized for each observer. The experiment was conducted under controlled lighting, temperature, and sound conditions to mimic conditions typically found in a patient examination room. Lighting was indirect, and illuminance at the display face was 195 ± 8% lux and was monitored over the course of the experiment. The average observer sensitivity for the 2 MP color consumer, 2 MP business color, 2 MP gray, and 3 MP gray displays were 83.7%, 84.1%, 85.5%, and 86.7%, respectively. The only pairwise significant difference was between the 2-MP consumer color and the 2-MP gray (P = 0.05). Effect of order within a session was not signitfficant (P = 0.21): period 1 (84.3%), period 2 (86.2%), period 3 (85.4%), period 4 (84.1%). Observer specificity for the various displays was not statistically significant (P = 0.21). Finally, a timing analysis showed no significant difference between the displays for the user group (P = 0.13), ranging from 5.3 s (2 MP color business) to 5.9 s (3 MP Gray). There was, however, a reduction in time over the study that was significant (P <<< 0.001) for all users; the group average decreased from 6.5 to 4.7 s per image. Physical measurements of the resolution, contrast, and noise properties of the displays were acquired. Most notably, the noise of the displays varied by 3.5× between the lowest and highest noise displays. Differences in display noise were indicative of observer performance. However, the large difference in the magnitude of the noise was not predictive of the small difference (3%) in the observer sensitivity for various displays. This is likely because detection of interstitial lung disease is limited by “““““anatomical noise””” rather than display or x-ray image noise.
PMCID: PMC3043952  PMID: 16249836
ROC; image quality; displays; interstitial lung disease
3.  SCAR R&D Symposium 2003: Comparing the Efficacy of 5-MP CRT Versus 3-MP LCD in the Evaluation of Interstitial Lung Disease  
Journal of Digital Imaging  2004;17(3):149-157.
The efficacy of two medical-grade, self-calibrating, gray scale displays were compared with regard to impact on sensitivity and specificity for the detection of interstitial lung disease (ILD) on computed radiographs (CR). The displays were a 5-megapixel (MP) cathode ray tube (CRT) device and a 3-MP liquid crystal display (LCD). A sample consisting of 230 anteroposterior (AP), posteroanterior (PA), and lateral views of the chest with CT-proven findings characteristic for ILD as well as 80 normal images were compared. This double-blinded trial produced a sample sufficient to detect if the sensitivity of the LCD was 10% or more reduced (one-sided) from the “gold standard” CRT display. Both displays were calibrated to the DICOM gray scale standard and the coefficient of variation of the luminance function varied less than 2% during the study. Five board-certified radiologists specializing in thoracic radiology interpreted the sample on both displays and the intraobserver Az (area under the ROC curve) showed no significant correlation to the display used. In addition, an interobserver kappa analysis showed that the relative disagreement between any observer pair remained relatively constant between displays, and thus was display invariant. This study demonstrated there is no significant change in observer performance sensitivity on 5-MP CRT versus 3-MP LCD displays for CR examinations demonstrating ILD of the chest.
PMCID: PMC3046602  PMID: 15534750
ROC; kappa; image quality; displays; interstitial lung disease; receiver operating characteristic

Results 1-3 (3)