Katherine P. Andriole

Recurrent CT, Cumulative Radiation Exposure, and Associated Radiation-induced Cancer Risks from CT of Adults

PURPOSE To estimate cumulative radiation exposure and lifetime attributable risk (LAR) of radiation-induced cancer from computed tomographic (CT) scanning of adult patients at a tertiary care academic medical center. MATERIALS AND METHODS This HIPAA-compliant study was approved by the institutional review board with waiver of informed consent. The cohort comprised 31,462 patients who underwent diagnostic CT in 2007 and had undergone 190,712 CT examinations over the prior 22 years. Each patients cumulative CT radiation exposure was estimated by summing typical CT effective doses, and the Biological Effects of Ionizing Radiation (BEIR) VII methodology was used to estimate LAR on the basis of sex and age at each exposure. Billing ICD9 codes and electronic order entry information were used to stratify patients with LAR greater than 1%. RESULTS Thirty-three percent of patients underwent five or more lifetime CT examinations, and 5% underwent between 22 and 132 examinations. Fifteen percent received estimated cumulative effective doses of more than 100 mSv, and 4% received between 250 and 1375 mSv. Associated LAR had mean and maximum values of 0.3% and 12% for cancer incidence and 0.2% and 6.8% for cancer mortality, respectively. CT exposures were estimated to produce 0.7% of total expected baseline cancer incidence and 1% of total cancer mortality. Seven percent of the cohort had estimated LAR greater than 1%, of which 40% had either no malignancy history or a cancer history without evidence of residual disease. CONCLUSION Cumulative CT radiation exposure added incrementally to baseline cancer risk in the cohort. While most patients accrue low radiation-induced cancer risks, a subgroup is potentially at higher risk due to recurrent CT imaging.

Lung volumes and emphysema in smokers with interstitial lung abnormalities.

BACKGROUND Cigarette smoking is associated with emphysema and radiographic interstitial lung abnormalities. The degree to which interstitial lung abnormalities are associated with reduced total lung capacity and the extent of emphysema is not known. METHODS We looked for interstitial lung abnormalities in 2416 (96%) of 2508 high-resolution computed tomographic (HRCT) scans of the lung obtained from a cohort of smokers. We used linear and logistic regression to evaluate the associations between interstitial lung abnormalities and HRCT measurements of total lung capacity and emphysema. RESULTS Interstitial lung abnormalities were present in 194 (8%) of the 2416 HRCT scans evaluated. In statistical models adjusting for relevant covariates, interstitial lung abnormalities were associated with reduced total lung capacity (-0.444 liters; 95% confidence interval [CI], -0.596 to -0.292; P<0.001) and a lower percentage of emphysema defined by lung-attenuation thresholds of -950 Hounsfield units (-3%; 95% CI, -4 to -2; P<0.001) and -910 Hounsfield units (-10%; 95% CI, -12 to -8; P<0.001). As compared with participants without interstitial lung abnormalities, those with abnormalities were more likely to have a restrictive lung deficit (total lung capacity <80% of the predicted value; odds ratio, 2.3; 95% CI, 1.4 to 3.7; P<0.001) and were less likely to meet the diagnostic criteria for chronic obstructive pulmonary disease (COPD) (odds ratio, 0.53; 95% CI, 0.37 to 0.76; P<0.001). The effect of interstitial lung abnormalities on total lung capacity and emphysema was dependent on COPD status (P<0.02 for the interactions). Interstitial lung abnormalities were positively associated with both greater exposure to tobacco smoke and current smoking. CONCLUSIONS In smokers, interstitial lung abnormalities--which were present on about 1 of every 12 HRCT scans--were associated with reduced total lung capacity and a lesser amount of emphysema. (Funded by the National Institutes of Health and the Parker B. Francis Foundation; ClinicalTrials.gov number, NCT00608764.).

Addressing the Coming Radiology Crisis—The Society for Computer Applications in Radiology Transforming the Radiological Interpretation Process (TRIP™) Initiative

The Society for Computer Applications in Radiology (SCAR) Transforming the Radiological Interpretation Process (TRIP™) Initiative aims to spearhead research, education, and discovery of innovative solutions to address the problem of information and image data overload. The initiative will foster interdisciplinary research on technological, environmental and human factors to better manage and exploit the massive amounts of data. TRIP™ will focus on the following basic objectives: improving the efficiency of interpretation of large data sets, improving the timeliness and effectiveness of communication, and decreasing medical errors. The ultimate goal of the initiative is to improve the quality and safety of patient care. Interdisciplinary research into several broad areas will be necessary to make progress in managing the ever-increasing volume of data. The six concepts involved are human perception, image processing and computer-aided detection (CAD), visualization, navigation and usability, databases and integration, and evaluation and validation of methods and performance. The result of this transformation will affect several key processes in radiology, including image interpretation; communication of imaging results; workflow and efficiency within the health care enterprise; diagnostic accuracy and a reduction in medical errors; and, ultimately, the overall quality of care.

Computers in imaging and health care: Now and in the future

Early picture archiving and communication systems (PACS) were characterized by the use of very expensive hardware devices, cumbersome display stations, duplication of database content, lack of interfaces to other clinical information systems, and immaturity in their understanding of the folder manager concepts and workflow reengineering. They were implemented historically at large academic medical centers by biomedical engineers and imaging informaticists. PACS were nonstandard, home-grown projects with mixed clinical acceptance. However, they clearly showed the great potential for PACS and filmless medical imaging. Filmless radiology is a reality today. The advent of efficient softcopy display of images provides a means for dealing with the ever-increasing number of studies and number of images per study. Computer power has increased, and archival storage cost has decreased to the extent that the economics of PACS is justifiable with respect to film. Network bandwidths have increased to allow large studies of many megabytes to arrive at display stations within seconds of examination completion. PACS vendors have recognized the need for efficient workflow and have built systems with intelligence in the mangement of patient data. Close integration with the hospital information system (HIS)-radiology information system (RIS) is critical for system functionality. Successful implementation of PACS requires integration or interoperation with hospital and radiology information systems. Besides the economic advantages, secure rapid access to all clinical information on patients, including imaging studies, anytime and anywhere, enhances the quality of patient care, although it is difficult to quantify. Medical image management systems are maturing, providing access outside of the radiology department to images and clinical information throughout the hospital or the enterprise via the Internet. Small and medium-sized community hospitals, private practices, and outpatient centers in rural areas will begin realizing the benefits of PACS already realized by the large tertiary care academic medical centers and research institutions. Hand-held devices and the Worldwide Web are going to change the way people communicate and do business. The impact on health care will be huge, including radiology. Computer-aided diagnosis, decision support tools, virtual imaging, and guidance systems will transform our practice as value-added applications utilizing the technologies pushed by PACS development efforts. Outcomes data and the electronic medical record (EMR) will drive our interactions with referring physicians and we expect the radiologist to become the informaticist, a new version of the medical management consultant.

ACR–AAPM–SIIM Technical Standard for Electronic Practice of Medical Imaging

This technical standard has been revised by the American College of Radiology (ACR), the American Association of Physicists in Medicine (AAPM), and the Society for Imaging Informatics in Medicine (SIIM). For the purpose of this technical standard, the images referred to are those that diagnostic radiologists would normally interpret, including transmission projection and cross-sectional X-ray images, ionizing radiation emission images, and images from ultrasound and magnetic resonance modalities. Research, nonhuman and visible light images (such as dermatologic, histopathologic, or endoscopic images) are out of scope, though many of the same principles are applicable. Increasingly, medical imaging and patient information are being managed using digital data during acquisition, transmission, storage, display, interpretation, and consultation. The management of these data during each of these operations may have an impact on the quality of patient care. This technical standard is applicable to any system of digital image data management, from a single-modality or single-use system to a complete picture archiving and communication system (PACS) to the electronic transmission of patient medical images from one location to another for the purposes of interpretation and/or consultation. It defines goals, qualifications of personnel, equipment guidelines, specifications of data manipulation and management, and quality control and quality improvement procedures for the use of digital image data that should result in high-quality radiological care. A glossary of commonly used terminology (Appendix A) and a reference list are included. In all cases for which an ACR practice guideline or technical standard exists for the modality being used or the specific examination being performed, that practice guideline or technical standard will continue to apply when digital image data management systems are used. Digital mammography is outside the scope of this document. For further information, see the ACR–AAPM–SIIM Practice Guideline for Determinants of Image Quality in Digital Mammography. The goals of the electronic practice of medical imaging include, but are not limited to: Initial acquisition or generation and recording of accurately labeled and identified image data. Transmission of data to an appropriate storage medium from which it can be retrieved for display for formal interpretation, review, and consultation. Retrieval of data from available prior imaging studies to be displayed for comparison with a current study. Transmission of data to remote sites for consultation, review, or formal interpretation. Appropriate compression of image data to facilitate transmission or storage, without loss of clinically significant information. Archiving of data to maintain accurate patient medical records in a form that: May be retrieved in a timely fashion Meets applicable facility, state, and federal regulations Maintains patient confidentiality Promoting efficiency and quality improvement. Providing interpreted images to referring providers. Supporting telemedicine by making medical image consultations available in medical facilities without on-site medical imaging support. Providing supervision of off-site imaging studies. Providing timely availability of medical images, image consultation, and image interpretation by: Facilitating medical image interpretations in on-call situations Providing subspecialty support as needed. Enhancing educational opportunities for practicing radiologists. Minimizing the occurrence of poor image quality. Appropriate database management procedures applicable to all of the above should be in place.

Productivity and Cost Assessment of Computed Radiography, Digital Radiography, and Screen-Film for Outpatient Chest Examinations

An objective assessment and comparison of computed radiography (CR) versus digital radiography (DR) and screen-film for performing upright chest examinations on outpatients is presented in terms of workflow, productivity, speed of service, and potential cost justification. Perceived ease of use and workflow of each device is collected via a technologist opinion survey. Productivity is measured as the rate of patient throughput from normalized timing studies. The overall speed of service is calculated from the time of examination ordering as stamped in the radiology information system (RIS), to the time of image availability on the picture archiving and communication system (PACS), to the time of interpretation rendered (from the RIS). A cost comparison is discussed in terms of potential productivity gains and device expenditures. Comparative results of a screen-film (analog) dedicated chest unit versus a CR reader and a DR dedicated chest unit show a higher patient throughput for the digital systems. A mean of 8.2 patients were moved through the analog chest room per hour, versus 9.2 patients per hour using the CR system and 10.7 patients per hour with the DR system. This represents a 12% increase in patient throughput for CR over screen-film; a 30% increase in patient throughput for DR over screen-film, which is statistically significant; and a 16% increase in patient throughput for DR over CR, which is not statistically significant. Measured time to image availability for interpretation is much faster for both CR and DR versus screen-film, with the mean minutes to image availability calculated as 29.2 ± 14.3 min for screen-film, 6.7 ± 1.5 min for CR, and 5.7 ± 2.5 min for DR. This represents an improved time to image availability of 77% for CR over screen-film, 80% for DR over screen-film, and 15% for DR over CR. These results are statistically significant (P <.0001) for both CR over screen-film and DR over screen-film but not statistically significant for DR over CR. A comparison of the digital technology costs illustrates that the high cost of DR may not be justifiable unless a facility has a steady high patient volume to run the device at or near 100% productivity. Both CR and DR can improve workflow and productivity over analog screen-film in a PACS for delivery of projection radiography services in an outpatient environment. Cost justification for DR over CR appears to be tied predominantly to high patient volume and continuous rather than sporadic use patterns.

Incidence of pulmonary embolism in oncologic outpatients at a tertiary cancer center

Incidence of pulmonary embolism (PE) for different cancer types in oncology outpatients is unknown. The purposes of the current study is to determine the incidence of PE in oncology outpatients and to investigate whether the incidence for PE is higher in certain cancers.

Implementation of a large-scale picture archiving and communication system

This paper describes the implementation of a large-scale picture archiving and communication system (PACS) in a clinical environment. The system consists of a PACS infrastructure, composed of a PACS controller, a database management system, communication networks, and optical disk archive. It connects to three MR units, four CT scanners, three computed radiography systems, and two laser film digitizers. Seven display stations are on line 24 h/day, 7 days/wk in genitourinary radiology (2K), pediatric radiology in-patient (1K and 2K) and outpatient (2K), neuroradiology (2K), pediatric ICU (1K), coronary care unit (1K), and one laser film printing station. The PACS is integrated with the hospital information system and the radiology information system. The system has been in operation since February 1992. We have integrated this PACS as a clinical component in daily radiology practice. It archives an average of 2.0-gigabyte image data per workday. A 3-mo system performance of various components are tabulated. The deployment of this large-scale PACS signifies a milestone in our PACS research and development effort. Radiologists, fellows, residents, and clinicians use it for case review, conferences, and occasionally for primary diagnosis. With this large-scale PACS in place, it will allow us to investigate the two critical issues raised when PACS research first started 10 yrs ago: system performance and cost effectiveness between a digital-based and a film-based system.

Factors Associated With Radiologists' Adherence to Fleischner Society Guidelines for Management of Pulmonary Nodules

PURPOSE In 2005, the Fleischner Society guidelines (FSG) for managing pulmonary nodules detected on CT scans were published. The aim of this study was to evaluate adherence to the FSG, adjusting for demographic and clinical variables that may contribute to adherence. METHODS Radiology reports were randomly obtained for 1,100 chest and abdominal CT scans performed between January and June 2010 in a tertiary hospitals emergency department and outpatient clinics. An automated document retrieval system using natural language processing was used to identify patients with pulmonary nodules from the data set. Features relevant to evaluating variation in adherence to the FSG, including age, sex, race, nodule size, and scan site (eg, the emergency department) and type, were extracted by manual review from reports retrieved using natural language processing. All variables were entered into a logistic regression model. RESULTS Three hundred fifteen reports were identified to have pulmonary nodules, 75 of which were for patients with concurrent malignancies or aged < 35 years. Of the remaining 240 reports, 34% of recommendations for pulmonary nodules were adherent to the FSG. Nodule size demonstrated an association with guideline adherence, with adherence highest in the >4-mm to 6-mm nodule group (P = .04) and progressively diminishing for smaller and bigger nodules. CONCLUSIONS Pulmonary nodules are prevalent findings on chest and abdominal CT scans. Although most radiologists recommend follow-up imaging for these findings, recommendations for pulmonary nodules were consistent with the FSG in 34% of radiology reports. Nodule size demonstrated an association with guideline adherence, after adjusting for key variables.

Exposing Exposure: Automated Anatomy-specific CT Radiation Exposure Extraction for Quality Assurance and Radiation Monitoring

PURPOSE To develop and validate an informatics toolkit that extracts anatomy-specific computed tomography (CT) radiation exposure metrics (volume CT dose index and dose-length product) from existing digital image archives through optical character recognition of CT dose report screen captures (dose screens) combined with Digital Imaging and Communications in Medicine attributes. MATERIALS AND METHODS This institutional review board-approved HIPAA-compliant study was performed in a large urban health care delivery network. Data were drawn from a random sample of CT encounters that occurred between 2000 and 2010; images from these encounters were contained within the enterprise image archive, which encompassed images obtained at an adult academic tertiary referral hospital and its affiliated sites, including a cancer center, a community hospital, and outpatient imaging centers, as well as images imported from other facilities. Software was validated by using 150 randomly selected encounters for each major CT scanner manufacturer, with outcome measures of dose screen retrieval rate (proportion of correctly located dose screens) and anatomic assignment precision (proportion of extracted exposure data with correctly assigned anatomic region, such as head, chest, or abdomen and pelvis). The 95% binomial confidence intervals (CIs) were calculated for discrete proportions, and CIs were derived from the standard error of the mean for continuous variables. After validation, the informatics toolkit was used to populate an exposure repository from a cohort of 54 549 CT encounters; of which 29 948 had available dose screens. RESULTS Validation yielded a dose screen retrieval rate of 99% (597 of 605 CT encounters; 95% CI: 98%, 100%) and an anatomic assignment precision of 94% (summed DLP fraction correct 563 in 600 CT encounters; 95% CI: 92%, 96%). Patient safety applications of the resulting data repository include benchmarking between institutions, CT protocol quality control and optimization, and cumulative patient- and anatomy-specific radiation exposure monitoring. CONCLUSION Large-scale anatomy-specific radiation exposure data repositories can be created with high fidelity from existing digital image archives by using open-source informatics tools.