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1.  Image Quality Assurance in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial Network of the National Lung Screening Trial 
Journal of Digital Imaging  2005;18(3):242-250.
The National Lung Screening Trial is evaluating the effectiveness of low-dose spiral CT and conventional chest X-ray as screening tests for persons who are at high risk for developing lung cancer. This multicenter trial requires quality assurance (QA) for the image quality and technical parameters of the scans. The electronic system described here helps manage the QA process. The system includes a workstation at each screening center that de-identifies the data, a DICOM storage service at the QA Coordinating Center, and Web-based systems for presenting images and QA evaluation forms to the QA radiologists. Quality assurance data are collated and analyzed by an independent statistical organization. We describe the design and implementation of this electronic QA system, emphasizing issues relating to data security and privacy, the various obstacles encountered in the installation of a common system at different participating screening centers, and the functional success of the system deployed.
PMCID: PMC3046711  PMID: 15924251
Clinical trial; quality assurance; VPN; NLST
4.  Perceived fidelity of compressed and reconstructed radiological images: A preliminary exploration of compression, luminance, and viewing distance 
Journal of Digital Imaging  1998;11(4):168-175.
The authors’ goal was to explore the impact of image compression algorithm and ratio, image luminance, and viewing distance on radiologists’ perception of reconstructed image fidelity. Five radiologists viewed 16 sets of four hard-copy chest radiographs prepared for secondary interpretation. Each set included one uncompressed, and three compressed and reconstruted images prepared using three different algorithms but the same compression ratio. The sets were prepared using two subjects, four compression ratios (10∶1, 20∶1, 30∶1, 40∶1), and two luminance levels (2,400 cd/m2, standard lightbox illumination, and 200 cd/m2, simulating a typical CRT display). Readers ranked image quality and evaluated obviousness and clinical importance of differences. Viewing distances for image screening, inspection, and comparison were recorded. At 10∶1 compression, the compressed and uncompressed images were nearly indistinguishable; the three algorithms were very similar, and differences were rated “not obvious” and “not important.” At higher compression, readers consistently preferred uncompressed images, with notable differences between algorithms. The obviousness and clinical importance of differences were rated higher at lightbox luminance. Viewing distances appeared to be idiosyncratic
PMCID: PMC3453155  PMID: 9848049
thorax; radiography; images; compression; fidelity

Results 1-4 (4)