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AJR 2003; 180:1243-1246
© American Roentgen Ray Society


Computers in Radiology

Web-Based Image Review and Data Acquisition for Multiinstitutional Research

C. Craig Blackmore1,2, Michael L. Richardson1, Ken F. Linnau1, Amber M. Schwed1, Friedrich M. Lomoschitz3, Eva M. Escobedo1, John C. Hunter1, Gregory J. Jurkovich2,4 and Peter Cummings2

1 Department of Radiology, Harborview Medical Center, Box 359728, 325 Ninth Ave., Seattle, WA 98104.
2 Harborview Injury Prevention and Research Center, Harborview Medical Center, Seattle, WA 98104.
3 Department of Radiology, University of Vienna, Waehringer Guertel 18-20, A-1090, Vienna, Austria.
4 Department of Surgery, Harborview Medical Center, University of Washington, Seattle, WA 98104.

Received August 22, 2002; accepted after revision September 19, 2002.

 
Selected to be presented at the annual meeting of the American Roentgen Ray Society, San Diego, May 2003.

Supported in part by the Agency for Healthcare Research and Quality (grant K08 HS11291).

Address correspondence to C. C. Blackmore.


Abstract
Top
Abstract
Introduction
The Research Project
Discussion
References
 
OBJECTIVE. In this article, we describe a user-friendly Web-based interface that allows review of images combined with integrated data collection and entry for use at multiple sites involved in a large multicenter research project.

CONCLUSION. The Web-based system that we present uses a commercially available Internet browser and Web platform and allows automated data entry that can be easily uploaded into standard data analysis programs. The system simplifies the complex logistics of using multiple sites and reviewers for radiology research and can preserve human subject confidentiality. We tested the system using a large-scale multicenter cohort study of pelvic fracture–related hemorrhage (the "Evaluating Pelvic Hemorrhage" study). Program testing revealed seamless remote image interpretation and data acquisition.


Introduction
Top
Abstract
Introduction
The Research Project
Discussion
References
 
Performance of multicenter radiology research may involve interpretation of images at multiple sites and from different institutions. The radiologists who interpret the images may be widely spaced physically and temporally. Traditional methods of hard-copy review on film alternators require the physical presence of the investigator and are logistically challenging. In addition, hard-copy images are expensive to create, heavy to move, and bulky to store.

The advent of PACS (picture archiving and communication system) has brought tremendous speed and flexibility to image display. With PACS, electronic review of images from geographically distant sites is possible. However, special interfaces may be required, and the inclusion of patient-specific data on PACS images may violate human subjects' confidentiality requirements. Furthermore, PACS contains no capability for integrated data collection. The use of a Web-based interface for simultaneous image review and data collection has the potential to avoid the limitations of these other systems.

In this article, we describe a user-friendly Web-based system for multisite image interpretation and automated data collection developed for an ongoing large-scale multicenter cohort study. This system is based on a commercially available Internet browser and Web platform and allows automated entry of data that can then be easily uploaded into standard data analysis programs. The system simplifies the complex logistics of using multiple sites and reviewers for radiology research and can satisfy the need to preserve patient confidentiality in research studies. This system has broad potential applications in radiology research.


The Research Project
Top
Abstract
Introduction
The Research Project
Discussion
References
 
Pelvic Hemorrhage Study
The "Evaluating Pelvic Hemorrhage" study is a federally funded multiinstitutional study of radiographic and clinical predictors of major hemorrhage resulting from pelvic fracture. More than 800 subjects are currently enrolled in the study. The study data include the review of pelvic radiographs of trauma patients. For more recent cases, radiographs were made available by directly downloading the data from a hospital PACS. Radiographs from less recent cases were digitized using a digital camera (CS3030; Olympus, Tokyo, Japan). Both the downloaded and digitized gray-scale image files were posted on the study Web site in the JPEG (Joint Photographic Experts Group) File Interchange Format using a compression ratio of approximately 1:10 (Photoshop [version 6.0]; Adobe Systems, San Jose, CA). Image contrast was optimized for computer display, and all patient information was removed from the images, which were subsequently identified by research study number only.

Image interpretation.—The pelvic radiographs for each study subject were analyzed by one or more of five investigators located at multiple sites in the United States and Europe. For each subject, a series of 14 determinations regarding the location and extent of bony injury were made from the radiographs by the investigators and entered into a database for analysis. Included were identification of any fractures of the iliac wing, the sacrum, the obturator ring, the acetabulum, and the sciatic notch. If a fracture was identified, the extent of displacement was characterized as 5 mm or smaller or as larger than 5 mm. Reviewers noted if the sacroiliac joints were normal, or if diastatic, whether they were less than 10 mm, 10–30 mm, or greater than 30 mm. From the radiographic findings, the radiologist reviewers also determined the suspected injury pattern (anteroposterior compression; lateral compression; vertical shear; combination; anterior pelvic ring injury only; unknown mechanism). The pelvic radiographs were interpreted, the questions answered, and the data automatically collected through the Evaluating Pelvic Hemorrhage study Web site.

Web site.—The Evaluating Pelvic Hemorrhage study Web site is based on a commercially available Web content management system (Manila; Userland Software, Burlingame, CA) and operates using an on-site server system (ProLiant 2500; Compaq Computer, Cupertino, CA). Access to the Web site is password-protected and limited to the investigators only. The home page contains an introduction explaining the purpose of the research study as well as a summary about how the Web site works.

Each of the radiologist reviewers has a home page on the study Web site with links to detailed instructions about the research questions. The pelvic radiographs are organized into modules of 10 cases each. Reviewers navigate through the modules by way of links with access to detailed instructions available on each page. Once a module has been completed, the research Webmaster removes the link to the module from the reviewer's work list. The investigators' Web sites also provide lists of modules completed, with links to new modules that have not yet been interpreted (Fig. 1). Each reviewer has a different set of modules, but to assess inter- and intrareviewer variability, we assigned some cases and modules to more than one reviewer. This joint assignment was performed simply by adding links from the image files to the investigator Web pages. Web site management and image loading are performed by a part-time undergraduate in the work–study program.



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Fig. 1. Screen image shows radiologist reviewer's home page displays work list. "Completed" indicates that assessment data of 10 cases included in this module have been successfully appended to central study database and that links to individual images have been removed. Clicking on underlined module (e.g., "Module 909") opens link to pelvic radiograph that has not been assessed. At all times during assessment process, reviewers can access "Help" pages for navigation through Web site by clicking on link to "Introduction" and can access guidelines for radiographic assessment by clicking on link to "Instructions."

 

The basic layout of a individual case overview is a quarter-screen image of the pelvic radiograph with adjacent questions to be answered (Fig. 2). Reviewers click on the image to open a full-screen image of the pelvic radiograph in a different window. The size of the full-screen image approximates the size of the digital images produced in hard-copy format for clinical use. The New window option allows reviewers to go back and forth between the questions and the actual-size image. Questions are answered by clinking on one of several radio buttons, each of which represents a different response. At the end of the question list, a series of indicators prompt the reviewers if any questions remain unanswered.



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Fig. 2. Screen image shows central components of individual case overview. Pelvic radiograph is displayed on right half of screen, and adjacent list of questions with radio buttons are shown on left. Once radiologist reviewer answers all questions by clicking on respective radio button, reviewer can activate link for submitting assessment data ("Submit" button). Questions left unanswered are highlighted by series of indicators that appear above Submit button. Alternatively, reviewer can erase given answers by clicking "Reset" button before data submission. From each case, reviewer may choose "Next Case" link to proceed to next case or link to return to work list for entire module (e.g., "Return to Module 901").

 

Data entry.—After each case has been completed, the reviewer clicks the "Submit" button, which sends the data to a CGI (Common Gateway Interface) program written in Perl (Practical Extraction and Report Language). This program performs several tasks, including validating the data, sending feedback to the reviewer who submitted the data, storing the data in a database, and sending the data to the study coordinators via e-mail.

If a reviewer attempts to submit data with unanswered questions, the Web server prompts the user to go back and enter any missing data. Once all the questions have been answered, clicking on the Submit button presents a screen to the reviewer echoing all the responses to the study questions. This feedback screen shows the reviewer that the information was received safely and was entered correctly into the database (Fig. 3). The reviewers are then prompted to start the next case. The assessment data received from reviewers are time- and date-stamped and appended automatically to the study database. As a backup, the program immediately sends the data to an e-mail account managed by study coordinators. These e-mails are filed and organized according to their case number. The data accumulating in the database are periodically harvested and uploaded to a standard database (Excel 2000, Microsoft, Redmond, WA; or Stata 6.0, Stata, College Station, TX) for management and analysis. The system is flexible and can be set to allow reviewers to return and change responses at a later date. The automated e-mail backup function corrects for multiple or erroneous data submission by the reviewers.



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Fig. 3. After reviewer has clicked "Submit" button, completion of individual case is indicated to reviewer via a feedback screen image that automatically pops up when Web server registers successful storage of data set. "Return to case" button sends reviewer back to completed case, from which reviewer may continue to review further cases or quit.

 

Protection of subject identities.—The posting of medical information on the World Wide Web presents potential risk of invasion of patient privacy due to public access to the Internet. We have made our Web site password-protected. To gain access to the Web site, reviewers must obtain an access code from the Web site study coordinator. More important, the images and case pages are all coded by study number only. No patient-identifying information is available anywhere on the Web site. These protections have met with the approval of our human subjects review committee and allow blinded review of study images.

Limitations
Setup of the CGI program requires advanced knowledge in Web server administration and Perl. The Perl script was created by one of the investigators and is not a part of the Web management content software. Composing the image cases requires some knowledge of HTML (Hypertext Markup Language) coding. However, in our system, coding is easily handled by a premedical undergraduate student who completed a 2-hr HTML training course. In addition, a reliable Web server must be available and maintained by technical staff. The server used in this study was also used for managing the departmental home page as well as Web-based electronic teaching files. A pitfall that we encountered was that the system could not be used during periods of scheduled and unscheduled server maintenance. We also encountered some sporadic variations in Web site layout between Macintosh and PC operating systems.

JPEG File Interchange Format was used for broad compatibility across various computer platforms and commercially available Web browsers. Loss of image information using the JPEG compression algorithm potentially limits diagnostic assessment of soft-copy radiographs. However, degradation of radiographic image quality due to JPEG compression is negligible at compression ratios up to 1:20 [1, 2]. Alternatively, image compression without data loss could be achieved using file formats such as JPEG-LS, PNG (Portable Network Graphics), or TIFF (tagged image file format) at the cost of larger image files.


Discussion
Top
Abstract
Introduction
The Research Project
Discussion
References
 
The use of the Internet for radiology research minimizes the burdens of performing multicenter research. The Evaluating Pelvic Hemorrhage study consists of radiographs of more than 800 subjects. Interpreting the images for the study would be impractical and substantially more expensive if image interpretation required physically moving and hanging the pelvic radiographs. Furthermore, the possibility of data loss and error is minimized by the automated and redundant data collection system.

Systems, such as the one described in this article, have the potential to enable large-scale multicenter trials of image interpretation and diagnostic accuracy. Studies need not be limited to a few investigators at a single institution, but investigators can take advantage of the widespread expertise and case experience of individuals at a virtually limitless number of institutions. This Web-based format also protects patient confidentiality and easily allows the study investigators to ensure the interpreting radiologist is unaware of patient information. Additional applications for this technology are also possible in continuing medical education and competency testing [3].


Acknowledgments
 
We thank Steve Breathour, Timothy Quagliaroli, and James Lyon-Hall for outstanding technical computer systems support.


References
Top
Abstract
Introduction
The Research Project
Discussion
References
 

  1. Erickson B, Manduca A, Palisson P, et al. Wavelet compression of medical images. Radiology 1998;206 : 599–607[Free Full Text]
  2. Ohgiya Y, Gokan T, Fujisawa H, Hamamizu K, Tanno K, Munechika H. Acute cerebral infarction: effect of JPEG compression on detection at CT. (abstr) Radiology 2001;221(S):155
  3. Richardson M, Norris T. On-line delivery of continuing medical education over the World-Wide Web: an on-line needs assessment. AJR 1997;168 :1161 –1164[Abstract/Free Full Text]

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This Article
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