Image compression and chest radiograph interpretation: image perception comparison between uncompressed chest radiographs and chest radiographs stored using 10:1 JPEG compression.

We have assessed the effect of 10:1 lossy (JPEG) compression on six board-certified radiologists' ability to detect three commonly seen abnormalities on chest radiographs. The study radiographs included 150 chest radiographs with one of four diagnoses: normal (n = 101), pulmonary nodule (n = 19), interstitial lung disease (n = 19), and pneumothorax (n = 11). Before compression, these images were printed on laser film and interpreted in a blinded fashion by six radiologists. Following an 8-week interval, the images were reinterpreted on an image display workstation after undergoing 10:1 lossy compression. The results for the compressed images were compared with those of the uncompressed images using receiver operating characteristic (ROC) analyses. For five of six readers, the diagnostic accuracy was higher for the uncompressed images than for the compressed images, but the difference was not significant (P > .1111). Combined readings for the uncompressed images were also more accurate when compared with the compressed images, but this difference was also not significant (P = .1430). The sensitivity, specificity, and accuracy values were 81.5%, 89.2%, and 86.7% for the compressed images, respectively, as compared with 78.9%, 94.5%, and 89.3% for the uncompressed images. There was no correlation between the readers' accuracy and their experience with soft-copy interpretation; the extent of radiographic interpretation experience had no correlation with overall interpretation accuracy. In conclusion, five of six radiologists had a higher diagnostic accuracy when interpreting uncompressed chest radiographs versus the same images modified by 10:1 lossy compression, but this difference was not statistically significant.

Picture archiving and communication systems planning: a methodology.

This article presents the Picture Archiving and Communication Systems (PACS) planning methodology used by the Department of Defense's (DOD) Joint Imaging Technology Project Office (JITPO). This methodology evaluates four areas of PACS planning and implementation: strategic planning, clinical scenario planning, installation planning, and implementation planning. The first task is to develop a PACS team, from the local facility, that will execute the program. A written PACS plan is developed by the JITPO, with active input and final say from the site's PACS team. This plan includes the PACS goals and objectives, clinical requirements, facility requirements, and the status of the implementation. This methodology, when applied fully at a military clinical site, has resulted in the site obtaining best "value" in terms of cost and performance by requiring the DOD's contracted PACS vendors to propose a PACS package that meets or exceeds the site's unique requirements. The identification of the requirements and the matching of a known PACS configuration with them has reduced the number of unknowns within the vendors' proposals and created true competition in both initial cost and the cost to maintain PACS in the maintenance years. Although there are certain factors unique to planning a military PACS, such as preselected vendors, the planning methodology described in this article should provide a valuable strategy for any hospital planning a PACS.

Acceptance testing of integrated picture archiving and communications systems.

An integrated picture archiving and communication system (PACS) is a large investment in both money and resources. With all of the components and systems contained in the PACS, a methodical set of protocols and procedures must be developed to test all aspects of the PACS within the short time allocated for contract compliance. For the Department of Defense (DoD), acceptance testing (AT) sets the protocols and procedures. Broken down into modules and test procedures that group like components and systems, the AT protocol maximizes the efficiency and thoroughness of testing all aspects of an integrated PACS. A standardized and methodical protocol reduces the probability of functionality or performance limitations being overlooked. The AT protocol allows complete PACS testing within the 30 days allocated by the digital imaging network (DIN)-PACS contract. AT shortcomings identified during the testing phase properly allows for resolution before complete acceptance of the system. This presentation will describe the evolution of the process, the components of the DoD AT protocol, the benefits of the AT process, and its significance to the successful implementation of a PACS. This is a US government work. There are no restrictions on its use.

Benchmark testing the Digital Imaging Network-Picture Archiving and Communications System proposal of the Department of Defense.

The Department of Defense issued a Request for Proposal (RFP) for its next generation Picture Archiving and Communications System in January of 1997. The RFP was titled Digital Imaging Network-Picture Archiving and Communications System (DIN-PACS). Benchmark testing of the proposed vendors' systems occurred during the summer of 1997. This article highlights the methods for test material and test system organization, the major areas tested, and conduct of actual testing. Department of Defense and contract personnel wrote test procedures for benchmark testing based on the important features of the DIN-PACS Request for Proposal. Identical testing was performed with each vendor's system. The Digital Imaging and Communications in Medicine (DICOM) standard images used for the Benchmark Testing included all modalities. The images were verified as being DICOM standard compliant by the Mallinckrodt Institute of Radiology, Electronic Radiology Laboratory. The Johns Hopkins University Applied Physics Laboratory prepared the Unix-based server for the DICOM images and operated it during testing. The server was loaded with the images and shipped to each vendor's facility for on-site testing. The Defense Supply Center, Philadelphia (DSCP), the Department of Defense agency managing the DIN-PACS contract, provided representatives at each vendor site to ensure all tests were performed equitably and without bias. Each vendor's system was evaluated in the following nine major areas: DICOM Compliance; System Storage and Archive of Images; Network Performance; Workstation Performance; Radiology Information System Performance; Composite Health Care System/Health Level 7 communications standard Interface Performance; Teleradiology Performance; Quality Control; and Failover Functionality. These major sections were subdivided into workable test procedures and were then scored. A combined score for each section was compiled from this data. The names of the involved vendors and the scoring for each is contract sensitive and therefore can not be discussed. All of the vendors that underwent the benchmark testing did well. There was no one vendor that was markedly superior or inferior. There was a typical bell shaped curve of abilities. Each vendor had their own strong points and weaknesses. A standardized benchmark protocol and testing system for PACS architectures would be of great value to all agencies planning to purchase a PACS. This added information would assure the purchased system meets the needed functional requirements as outlined by the purchasers PACS Request for Proposal.

Sciatic neuropathy secondary to migration of trochanteric wire following total hip arthroplasty.

Delayed sciatic neuropathy secondary to migration of a free segment of trochanteric wire in an otherwise successful total hip arthroplasty seems not to have been reported previously. A 60-year-old woman with a total hip arthroplasty with a lateral transtrochanteric approach had the trochanter reattached with two 18-gauge Vitallium wires. The osteotomy healed uneventfully despite a break in the vertical wire ten days after surgery. Five years and ten months later, the patient began to have severe sciatic pain. Roentgenograms showed a free fragment of trochanteric wire posterior to the hip joint. On exploration, the 2-cm wire fragment was found to lie entirely within the epineurium of the sciatic nerve.