Collecting 48,000 CT Exams for the Lung Screening Study of the National Lung Screening Trial
From 2002–2004, the Lung Screening Study (LSS) of the National Lung Screening Trial (NLST) enrolled 34,614 participants, aged 55–74 years, at increased risk for lung cancer due to heavy cigarette smoking. Participants, randomized to standard chest X-ray (CXR) or computed tomography (CT) arms at ten screening centers, received up to three imaging screens for lung cancer at annual intervals. Participant medical histories and radiologist-interpreted screening results were transmitted to the LSS coordinating center, while all images were retained at local screening centers. From 2005–2007, all CT exams were uniformly de-identified and delivered to a central repository, the CT Image Library (CTIL), on external hard drives (94%) or CD/DVD (5.9%), or over a secure Internet connection (0.1%). Of 48,723 CT screens performed, only 176 (0.3%) were unavailable (lost, corrupted, compressed) while 48,547 (99.7%) were delivered to the CTIL. Described here is the experience organizing, implementing, and adapting the clinical-trial workflow surrounding the image retrieval, de-identification, delivery, and archiving of available LSS–NLST CT exams for the CTIL, together with the quality assurance procedures associated with those collection tasks. This collection of CT exams, obtained in a specific, well-defined participant population under a common protocol at evenly spaced intervals, and its attending demographic and clinical information, are now available to lung-disease investigators and developers of computer-aided-diagnosis algorithms. The approach to large scale, multi-center trial CT image collection detailed here may serve as a useful model, while the experience reported should be valuable in the planning and execution of future equivalent endeavors.
Key wordsCancer detection chest CT clinical trial computed tomography de-identification lung diseases digital image management image database image libraries national lung screening trial lung screening study CT image library
This research was supported by contracts from the Division of Cancer Prevention, National Cancer Institute (NCI), NIH, DHHS. The authors thank Drs. Christine Berg, LSS-NLST Project Officer, and John Gohagan, former LSS-NLST Project Officer, Division of Cancer Prevention, National Cancer Institute; the Screening Center (Appendix A) investigators, coordinators, and staff of the National Lung Screening Trial (NLST); Mr. Tom Riley and staff, Information Management Services, Inc., and Ms. Brenda Brewer and staff, Westat, Inc, for their support and assistance. The Westat LSS component is supported by NCI Contract NO1-CN-25476. We thank Drs. Richard Fagerstrom and Timothy Church for their reviews of a preliminary version of the manuscript. We also thank our image viewers, without whom the CTIL would have been seriously delayed: Angelica Cosas, Patricia Rueweler, Rochelle Williams, Dr. Sooah Kim, Dr. Miyoung Kim, and Dr. Yuting Liang. The CTIL gratefully acknowledges Merge Healthcare’s generous contribution of the FUSION Server and its continued support under their research agreement with the Mallinckrodt Institute of Radiology. Most importantly, we acknowledge the LSS participants for their contributions to making this study possible.
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