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2.  Facial Recognition Software Success Rates for the Identification of 3D Surface Reconstructed Facial Images: Implications for Patient Privacy and Security 
Journal of Digital Imaging  2011;25(3):347-351.
Image de-identification has focused on the removal of textual protected health information (PHI). Surface reconstructions of the face have the potential to reveal a subject’s identity even when textual PHI is absent. This study assessed the ability of a computer application to match research subjects’ 3D facial reconstructions with conventional photographs of their face. In a prospective study, 29 subjects underwent CT scans of the head and had frontal digital photographs of their face taken. Facial reconstructions of each CT dataset were generated on a 3D workstation. In phase 1, photographs of the 29 subjects undergoing CT scans were added to a digital directory and tested for recognition using facial recognition software. In phases 2–4, additional photographs were added in groups of 50 to increase the pool of possible matches and the test for recognition was repeated. As an internal control, photographs of all subjects were tested for recognition against an identical photograph. Of 3D reconstructions, 27.5% were matched correctly to corresponding photographs (95% upper CL, 40.1%). All study subject photographs were matched correctly to identical photographs (95% lower CL, 88.6%). Of 3D reconstructions, 96.6% were recognized simply as a face by the software (95% lower CL, 83.5%). Facial recognition software has the potential to recognize features on 3D CT surface reconstructions and match these with photographs, with implications for PHI.
PMCID: PMC3348980  PMID: 22065158
Facial recognition; Privacy; 3D Reconstruction; 3D Imaging (imaging, three-dimensional); HIPPA
3.  Five Levels of PACS Modularity: Integrating 3D and Other Advanced Visualization Tools 
Journal of Digital Imaging  2011;24(6):1096-1102.
The current array of PACS products and 3D visualization tools presents a wide range of options for applying advanced visualization methods in clinical radiology. The emergence of server-based rendering techniques creates new opportunities for raising the level of clinical image review. However, best-of-breed implementations of core PACS technology, volumetric image navigation, and application-specific 3D packages will, in general, be supplied by different vendors. Integration issues should be carefully considered before deploying such systems. This work presents a classification scheme describing five tiers of PACS modularity and integration with advanced visualization tools, with the goals of characterizing current options for such integration, providing an approach for evaluating such systems, and discussing possible future architectures. These five levels of increasing PACS modularity begin with what was until recently the dominant model for integrating advanced visualization into the clinical radiologist's workflow, consisting of a dedicated stand-alone post-processing workstation in the reading room. Introduction of context-sharing, thin clients using server-based rendering, archive integration, and user-level application hosting at successive levels of the hierarchy lead to a modularized imaging architecture, which promotes user interface integration, resource efficiency, system performance, supportability, and flexibility. These technical factors and system metrics are discussed in the context of the proposed five-level classification scheme.
PMCID: PMC3222550  PMID: 21301923
PACS; 3D imaging (imaging, three-dimensional); Computer systems; Advanced visualization; Server-based rendering; Application hosting
4.  Computer Input Devices: Neutral Party or Source of Significant Error in Manual Lesion Segmentation? 
Journal of Digital Imaging  2010;24(1):135-141.
Lesion segmentation involves outlining the contour of an abnormality on an image to distinguish boundaries between normal and abnormal tissue and is essential to track malignant and benign disease in medical imaging for clinical, research, and treatment purposes. A laser optical mouse and a graphics tablet were used by radiologists to segment 12 simulated reference lesions per subject in two groups (one group comprised three lesion morphologies in two sizes, one for each input device for each device two sets of six, composed of three morphologies in two sizes each). Time for segmentation was recorded. Subjects completed an opinion survey following segmentation. Error in contour segmentation was calculated using root mean square error. Error in area of segmentation was calculated compared to the reference lesion. 11 radiologists segmented a total of 132 simulated lesions. Overall error in contour segmentation was less with the graphics tablet than with the mouse (P < 0.0001). Error in area of segmentation was not significantly different between the tablet and the mouse (P = 0.62). Time for segmentation was less with the tablet than the mouse (P = 0.011). All subjects preferred the graphics tablet for future segmentation (P = 0.011) and felt subjectively that the tablet was faster, easier, and more accurate (P = 0.0005). For purposes in which accuracy in contour of lesion segmentation is of the greater importance, the graphics tablet is superior to the mouse in accuracy with a small speed benefit. For purposes in which accuracy of area of lesion segmentation is of greater importance, the graphics tablet and mouse are equally accurate.
PMCID: PMC3046792  PMID: 20049624
Image segmentation; user-computer interface; computer assisted detection; computer hardware; data collection; human computer interaction; evaluation research; segmentation
5.  Digital Radiography Reject Analysis: Data Collection Methodology, Results, and Recommendations from an In-depth Investigation at Two Hospitals 
Reject analysis was performed on 288,000 computed radiography (CR) image records collected from a university hospital (UH) and a large community hospital (CH). Each record contains image information, such as body part and view position, exposure level, technologist identifier, and—if the image was rejected—the reason for rejection. Extensive database filtering was required to ensure the integrity of the reject-rate calculations. The reject rate for CR across all departments and across all exam types was 4.4% at UH and 4.9% at CH. The most frequently occurring exam types with reject rates of 8% or greater were found to be common to both institutions (skull/facial bones, shoulder, hip, spines, in-department chest, pelvis). Positioning errors and anatomy cutoff were the most frequently occurring reasons for rejection, accounting for 45% of rejects at CH and 56% at UH. Improper exposure was the next most frequently occurring reject reason (14% of rejects at CH and 13% at UH), followed by patient motion (11% of rejects at CH and 7% at UH). Chest exams were the most frequently performed exam at both institutions (26% at UH and 45% at CH) with half captured in-department and half captured using portable x-ray equipment. A ninefold greater reject rate was found for in-department (9%) versus portable chest exams (1%). Problems identified with the integrity of the data used for reject analysis can be mitigated in the future by objectifying quality assurance (QA) procedures and by standardizing the nomenclature and definitions for QA deficiencies.
PMCID: PMC3043667  PMID: 18446413
Reject analysis; quality assurance; digital radiography
6.  Pay for Performance (P4P) in Medical Imaging: The Time Has (Finally) Come 
Journal of Digital Imaging  2006;19(4):289-294.
PMCID: PMC3045155  PMID: 17136488
7.  Defining the PACS Profession: An Initial Survey of Skills, Training, and Capabilities for PACS Administrators 
Journal of Digital Imaging  2005;18(4):252-259.
The need for specialized individuals to manage picture archiving and communications systems (PACS) has been recognized with the creation of a new professional title: PACS administrator. This position requires skill sets that bridge the current domains of radiology technologists (RTs), information systems analysts, and radiology administrators. Health care organizations, however, have reported difficfiulty in defining the functions that a PACS administrator should perform—a challenge compounded when the tries to combine this complex set of capabilities into one individual. As part of a larger effort to define the PACS professional, we developed an extensive but not exclusive consensus list of business, technical, and behavioral competencies desirable in the dedicated PACS professional. Through an on-line survey, radiologists, RTs, information technology specialists, corporate information officers, and radiology administrators rated the importance of these competencies. The results of this survey are presented, and the implications for implementation in training and certification efforts are discussed.
PMCID: PMC3046727  PMID: 16249838
PACS administrator; PACS; radiology management; information systems management
8.  Evolution of the Digital Revolution: A Radiologist Perspective 
Journal of Digital Imaging  2004;16(4):324-330.
The transformation from film-based to filmless operation has become more and more challenging, as imaging studies expand in size and complexity. To adapt to these changes, radiologists must proactively develop new workflow strategies to compensate for increasing work demands and the existing workforce shortage. This article addresses the evolutionary changes underway in the radiology interpretation process and reviews changes that have occurred in the past decade. These include a number of developments in soft-copy interpretation, which is migrating from a relatively static process, duplicating film-based interpretation, to a dynamic process, using multi-planar reconstructions, volumetric navigation, and electronic decision support tools. The result is optimization of the human–computer interface with improved productivity, diagnostic confidence, and interpretation accuracy.
PMCID: PMC3044070  PMID: 14747936
evolution of radiology practice; radiology interpretation; Transforming the Radiology Interpretation Process (TRIP)
10.  Work Flow Redesign: The Key to Success When Using PACS  
Journal of Digital Imaging  2003;16(1):164-168.
OBJECTIVE. Our objective is to emphasize the importance of work flow redesign, rather than filmless operation itself, to achieve cost reduction and improvement in productivity with picture archiving and communication systems (PACS). CONCLUSION. Our 8-year experience with PACS shows that the greatest benefit of the transition to a digital system has been the ability to use it as a tool to reengineer overall work flow, both in the imaging department and throughout the health care enterprise.
PMCID: PMC3045140  PMID: 12945824
11.  SCAR Radiologic Technologist Survey: Analysis of the Impact of Digital Technologies on Productivity  
Journal of Digital Imaging  2002;15(3):132-140.
As medical reimbursements continue to decline, increasing financial pressures are placed upon medical imaging providers. This burden is exacerbated by the existing radiologic technologist (RT) crisis, which has caused RT salaries to trend upward. One strategy to address these trends is employing technology to improve technologist productivity. While industry-wide RT productivity benchmarks have been established for film-based operation, little to date has been published in the medical literature regarding similar productivity measures for filmless operation using PACS. This study was undertaken to document the complex relationship between technologist productivity and implementation of digital radiography and digital information technologies, including PACS and hospital/radiology information systems (HIS/RIS). A nationwide survey was conducted with 112 participating institutions, in varying degrees of digital technology implementation. Technologist productivity was defined as the number of annual exams performed per technologist full-time equivalent (FTE). Productivity analyses were performed among the different demographic and technology profile groups, with a focus on general radiography, which accounts for 65-70% of imaging department volumes. When evaluating the relationship between technologist productivity and digital technology implementation, improved productivity measures were observed for institutions implementing HIS/RIS, modality worklist, and PACS. The timing of PACS implementation was found to have a significant effect on technologist productivity measures, with an initial 10.8% drop in productivity during the first year of PACS implementation, followed by a 27.8% increase in productivity beyond year one. This suggests there is a "PACS learning curve" phenomenon, which should be considered when institutions are planning for PACS implementation.
PMCID: PMC3613256  PMID: 12481227
13.  Frequency and impact of high-resolution monitor failure in a filmless imaging department 
Journal of Digital Imaging  2000;13(3):114-118.
The purpose of this study was to assess the image quality and the rate of failure of the high-resolution (2,048×1536 pixel) monitors used for primary diagnosis in a filmless radiology department and to analyze the type of problems encountered as well as the action taken to repair the monitors. Data were collected from Picture Archival and Communication System (PACS) service logs to determine rates of monitor adjustment and replacement, the symptoms reported, and the action taken. Additionally, random surveys of the high-resolution monitors were performed using a standard test pattern to assess spatial and contrast resolution in the center and outer corners of the monitors. Analysis of monitor service records showed a high rate of monitor replacement (41% per year) resulting in a relatively short “life expectancy” (defined as average time required before replacement) of 2.4 years. Random surveys of monitor quality using a standard test pattern showed suboptimal image quality in approximately 54% of the monitors with moderate image quality degradation present in at least one region of 27% of the high-resolution monitors, despite our vendor’s quality control program. The results of this study support our subjective impression and those of other colleagues in the PACS community of an unacceptably high monitor failure rate and persistent image quality problems with 2,000 pixel monitors used for primary diagnosis. The relatively high incidence of suboptimal quality monitors suggests that more frequent quality control should be performed using a test pattern particularly given the fact that radiologists often are unable to discern degradation of monitor performance using clinical images. The high incidence of problems with image quality on high-resolution monitors indicates that vendors need to develop better quality control in monitor design and testing. Radiologists should review briefly a test pattern on each monitor at the beginning of each day. A computer program should be incorporated into the PACS, which asks radiologists to evaluate a test pattern and records the results in a central database, which is communicated to the service engineers. Further studies should be evaluated to determine the clinical impact of monitor image degradation, which is relatively easily seen using a test pattern but may be difficult to discern on clinical images. Requests for proposals (RFPs) for PACS and service contracts must specify carefully requirements for monitor image quality and conditions under which the vendor is required to replace these monitors.
PMCID: PMC3452968  PMID: 15359749
monitor; workstation; maintenance; reliability; PACS; soft-copy; filmless; Society of Motion Picture and Television Engineers; quality; repair; display; radiology
14.  Challenges associated with interfacing computed tomography to a picture archiving and communication system at the Baltimore Veterans Affairs Medical Center—A historical perspective 
Journal of Digital Imaging  2000;13(Suppl 1):83-87.
The interfacing of digital image acquisition modalities to the picture archiving and communication system (PACS) plays a major part in the conversion from a traditional film-based radiology practice to one that relies almost entirely on soft-copy reading. The Baltimore Veterans Affairs Medical Center (VAMC) is one of the first filmless hospitals in the world. Since 1993, it has used computed tomography (CT) scanners connected to a commercial PACS to provide digitized patient images for filmless reading. Over the years, the evolution of Digital Imaging and Communications in Medicine (DICOM) standards, advances in networking technologies, and enhancements in PACS and hospital information system (HIS) software have greatly improved this system’s robustness and patient/study identification accuracy. The result has been a major increase in productivity.
PMCID: PMC3453294  PMID: 10847370
15.  Challenges associated with the incorporation of digital radiography into a picture archival and communication system 
Journal of Digital Imaging  1999;12(Suppl 1):6-8.
Digital radiography (DR) has recently emerged as an attractive alternative to computed radiography (CR) for the acquisition of general radiographic studies in a digital environment. It offers the possibility of improved spatial and contrast resoltuion, decreased radiation dose due to improved effieincy of detection of x-ray photons, and perhaps most improtantly, holds out the promise of increased technologist productivity. To achieve maximum efficiency, DR must be completely integrated into existing information systems, including the hospital and radiology information systems (HIS/RIS) and, when present, the picture archival and communication system (PACS). The early experience with the integration of DR at the Baltimore Veterans Affairs Medical Center (VAMC) has identified several challenges that exist to the successful integration of DR. DR has only recently been defined as a separate Digital Imaging and Communications in Medicine (DICOM) modality and images obtained will, at first, be listed under the category of CR. Matrix sizes with some DR products on the market exceed the current size limitations of some PACS. The patient throughput may be substantially greater with DR than with CR, and this in combination with the larger size of image files may result in greater demands for network and computer performance in the process of communication with the HIS/RIS and PACS. Additionally, in a hybrid department using both CR and DR, new rules must be defined for prefetching and display of general radiographic studies to permit these examinations to be retrieved and compared together. Advanced features that are planned for DR systems, such as dualenergy subtraction, tomosynthesis, and temporal subtraction, will likely require additional workstation tools beyond those currently available for CR.
PMCID: PMC3452875  PMID: 10342154
16.  Mammo web continuing medical education (CME): A web-based breast imaging CME program 
Journal of Digital Imaging  1999;12(Suppl 1):124-126.
The ubiquity of the world-wide web allows unique educational opportunities for continuing medical education (CME). We have designed a comprehensive breast imaging CME curriculum to permit individual physicians in their homes or offices to use personal computers to ease the burden of this process. Category 1 CME credits can be earned off-hours without having the physician travel out of town. In addition, since the course in computer-based, the overall costs to the participant are substantially reduced. The program can be updated on an ongoing basis to include new technology or to provide additional information requested by the users.
PMCID: PMC3452881  PMID: 10342188
17.  Economic and clinical impact of filmless operation in a multifacility environment 
Journal of Digital Imaging  1998;11(Suppl 2):42-47.
The transition from conventional film-based to filmless operation at the Baltimore Veterans Affairs (VA) Medical Center has resulted in a large number of clinical and economic benefits. The integration of the Department of VA hospitals in Maryland into the VA Maryland Health Care System has resulted in the opportunity to establish a “virtual” radiology and nuclear medicine department. This integrated department is based on a wide area network in which outlying medical centers use a central hospital information system/radiology information system (HIS/RIS) and a central commercial picture archiving and communication system (PACS), as well as a VA-developed image management and communication system. The creation of this virtual radiology/nuclear medicine department has resulted in additional savings and improvements in clinical care. The benefits of the PACS are made possible, to a large extent, by the high level of integration of the PACS and medical modalities with the hospital information and transcription systems. Our experience suggests that it is absolutely essential to integrate the PACS into the patient’s electronic medical record to maximize efficiency and clinical effectiveness of the system.
PMCID: PMC3453322  PMID: 9848061
18.  Impact of filmless imaging on the frequency of clinician review of radiology images 
Journal of Digital Imaging  1998;11(Suppl 1):149-150.
The purpose of this study was to determine the impact of filmless imaging on the frequency with which physicians access radiology images and to assess clinician perception of image accessibility using a hospital-wide Picture Archival and Communication System (PACS). Quantitative data were collected at the Baltimore VA Medical Center (BVAMC), prior to and after conversion to filmless imaging, to determine the frequency with which clinicians access radiology images. Survey data were also collected to assess physician preferences of image accessibility, time management, and overall patient care when comparing filmless and film-based modes of operation. In general, there was a significant increase in the average number of radiology images reviewed by clinicians throughout the hospital. However, the one area in the hospital where this trend was not observed was in the intensive care unit (ICU), where the frequency of image access was similar between film and filmless operations. Ninety-eight percent of clinicians surveyed reported improved accessibility of images in a filmless environment resulting in improved time management. The mean clinician estimate of time saved due to the use of PACS was 44 minutes. The study documented a combination of clinician perception of improved accessibility and substantial time savings with the use of a hospital-wide PACS, which was supported by objective measurements. The increased frequency of image review by clinicians and rapid image access should provide a further impetus to radiologists to decrease report turnaround time to provide “added value” for patient care.
PMCID: PMC3453391  PMID: 9735455
19.  Comparison of three display methods for evaluating CT angiography data for the vascular assessment of renal donors 
Journal of Digital Imaging  1998;11(Suppl 1):145-148.
In conclusion, CTA display methods are useful when evaluating renal vascular anatomy. Cinematic loop appears to be the most useful display method and is significantly more sensitive, specific, and accurate than the 3D-MIP or stack axial when identifying renal arterial anatomy.
PMCID: PMC3453416  PMID: 9735454
20.  Recommendations for image prefetch or film digitization strategy based on an analysis of an historic radiology image database 
Journal of Digital Imaging  1998;11(2):94-99.
Picture archiving and communications systems (PACS) utilize short- and long-term storage to provide both rapid retrieval and large storage capacity. Owing to the practical limitations imposed on the size of the much faster short-term storage, it is important to use an effective algorithm in the retrieval of comparison images from long to short-term storage. A strategy must be used to maximize the likelihood that the relevant historic images have been previously retrieved into short-term memory. Data were collected with a database consisting of 754 consecutive examinations and 7,723 associated historic studies. The most frequent number of previous examinations was zero (11% of patients). In 45% of cases, no previous matching examinations had been performed. Two basic strategies of image retrieval were evaluated. The first algorithm retrieved the lastn studies in chronological order. The second strategy tested was retrieval based on a defined interval of time. This strategy was found to be less efficient. By using the former strategy, a 91% success rate (defined as successful retrieval of the previous matching exam) was achieved with retrieval of only 30% of the prior exams. The second approach required retrieval of 70% of the prior exams to achieve a 90% success rate for the previous matching exam. However, the data from this latter strategy suggest that examinations are often ordered in clusters. Thus, there was found to be a 72% likelihood that a previous matching exam, if present, would available on a PACS after only 1 week of operation, and an 80% chance after only 1 month of operation. The data therefore suggest that digitization of film in a new PACS environment might not be necessary owing to the relatively short period of time required to populate the database with historical studies.
PMCID: PMC3452997  PMID: 9608932
digital; computer; radiology; imaging; algorithm; workstation; efficiency; archival; storage; database; digitization
21.  Patterns of utilization of computer workstations in a filmless environment and implications for current and future picture archiving and communication systems 
Journal of Digital Imaging  1997;10(Suppl 1):41-43.
A workstation monitoring program can be implemented, which automatically creates a log of workstation utilization that can be exported for analysis on a conventional spreadsheet or database analysis program. This methodology has several drawbacks as described, which make it a relatively crude tool in the prediction of peak and average network traffic and optimal workstation deployment. A large-scale PACS should include system administration tools that permit the creation of a utilization log and subsequent analysis of all image and database accesses for each workstation. This tool should not result in measurable degradation of system performance and should be run on an ongoing basis. Such an administrative tool could provide critical information to vendors for system design, to customers for system planning, and to users for system optimization and maintenance.
PMCID: PMC3452826  PMID: 9268836
22.  Experience with comparative picture archiving and communication system baseline data collection at four Veterans Affairs Medical Centers: Methodology, lessons learned, and suggestions for improvement 
Journal of Digital Imaging  1997;10(Suppl 1):161-164.
Careful planning of the study and full support of the radiology staff are essential for collection of such data. It important to obtain pilot data to identify potential problems and adequately train personnel. Such pilot data should be compared with data collected automatically from the HIS, RIS, or PACS to establish the reliability of various data sources. When data was collected without using a study form compliance was low. It is important to automate the data collection as much as possible in order to keep the forms simple and as short as possible. This will increase substantially the consistency at which accurate data are captured.
PMCID: PMC3452864  PMID: 9268868

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