Richard Hanson

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.

Effect of Computerized Clinical Decision Support on the Use and Yield of CT Pulmonary Angiography in the Emergency Department

PURPOSE To determine the effect of evidence-based clinical decision support (CDS) on the use and yield of computed tomographic (CT) pulmonary angiography for acute pulmonary embolism (PE) in the emergency department (ED). MATERIALS AND METHODS Institutional review board approval was obtained for this HIPAA-compliant study, which was performed between October 1, 2003, and September 30, 2009, at a 793-bed quaternary care institution with 60,000 annual ED visits. Use (number of examinations per 1000 ED visits) and yield (percentage of examinations positive for acute PE) of CT pulmonary angiography were compared before and after CDS implementation in August 2007. The authors included all adult patients presenting to the ED and developed and validated a natural language processing tool to identify acute PE diagnoses. Linear trend analysis was used to assess for variation in CT pulmonary angiography use. Logistic regression was used to determine variation in yield after controlling for patient demographic and clinical characteristics. RESULTS Of 338,230 patients presenting to the ED, 6838 (2.0%) underwent CT pulmonary angiography. Quarterly CT pulmonary angiography use increased 82.1% before CDS implementation, from 14.5 to 26.4 examinations per 1000 patients (P<.0001) between October 10, 2003, and July 31, 2007. After CDS implementation, quarterly use decreased 20.1%, from 26.4 to 21.1 examinations per 1000 patients between August 1, 2007, and September 30, 2009 (P=.0379). Overall, 686 (10.0%) of the CT pulmonary angiographic examinations performed during the 6-year period were positive for PE; subsequent to CDS implementation, yield by quarter increased 69.0%, from 5.8% to 9.8% (P=.0323). CONCLUSION Implementation of evidence-based CDS in the ED was associated with a significant decrease in use, and increase in yield, of CT pulmonary angiography for the evaluation of acute PE.

Variation in Use of Head Computed Tomography by Emergency Physicians

OBJECTIVE Variation in emergency department head computed tomography (CT) use in patients with atraumatic headaches between hospitals is being measured nationwide. However, the magnitude of interphysician variation within a hospital is currently unknown. We hypothesized that there was significant variation in the rates of physician head CT use, both overall and for patients diagnosed with atraumatic headaches. METHODS This cross-sectional study was conducted in the emergency department of a large urban academic hospital, and institutional review board approval was obtained. All emergency department visits from 2009 were analyzed, and the primary outcome measure was whether or not head CT was performed. Logistic regression was used to control for patient, physician, and visit characteristics potentially associated with head CT ordering. The degree of interphysician variability was tested, both before and after controlling for these variables. RESULTS Of 55,286 emergency department patient encounters, 4919 (8.9%) involved head CT examinations. Unadjusted head CT ordering rates per physician ranged from 4.4% to 16.9% overall and from 15.2% to 61.7% in patients diagnosed with atraumatic headaches, with both rates varying significantly between physicians. Two-fold variation in head CT ordering overall (6.5%-13.5%) and approximately 3-fold variation in head CT ordering for atraumatic headaches (21.2%-60.1%) persisted even after controlling for pertinent variables. CONCLUSION Emergency physicians vary significantly in their use of head CT both overall and in patients with atraumatic headaches. Further studies are needed to identify strategies to reduce interphysician variation in head CT use.

Inpatient Radiology Utilization: Trends over the Past Decade

OBJECTIVE The objective of our study was to assess patterns of use of radiology services for inpatients at our institution between 1993 and 2002. MATERIALS AND METHODS We retrospectively reviewed the administrative data about adult inpatients for fiscal years 1993-2002 in a 721-bed tertiary care institution. Examinations were coded according to imaging technique: conventional (plain films and fluoroscopy), sonography, nuclear medicine, CT, or MRI. We assessed workload trends using relative value units (RVUs). Linear regression analysis was used to assess the significance of trends for the number of examinations and RVUs per case-mix-adjusted admission (CMAA). RESULTS There was a significant decrease in the total number of examinations per CMAA (p < 0.001). This was due to significant decreases in the use of conventional studies (p < 0.001) and sonograms (p < 0.001), despite significant increases in the number of nuclear medicine (p = 0.046), CT (p < 0.001), and MRI (p < 0.002) examinations per CMAA. The RVUs per CMAA increased significantly (p < 0.01) during the study period. CONCLUSION Newer imaging technologies (nuclear medicine, CT, and MRI) are replacing older ones in the evaluation of inpatients. Despite the significant decrease in the total number of imaging examinations per CMAA, we observed a significant increase in RVUs per CMAA during the 10-year study period. Understanding the impact of this change in practice on the quality of care would be useful in justifying the increasing use of these new technologies, and decreasing their inappropriate use should be a priority in efforts that focus on controlling imaging expenditures.

Business Intelligence Tools for Radiology: Creating a Prototype Model Using Open-Source Tools

Digital radiology departments could benefit from the ability to integrate and visualize data (e.g. information reflecting complex workflow states) from all of their imaging and information management systems in one composite presentation view. Leveraging data warehousing tools developed in the business world may be one way to achieve this capability. In total, the concept of managing the information available in this data repository is known as Business Intelligence or BI. This paper describes the concepts used in Business Intelligence, their importance to modern Radiology, and the steps used in the creation of a prototype model of a data warehouse for BI using open-source tools.

Abdominal imaging utilization in the emergency department: trends over two decades

BackgroundTo assess patterns of use of abdominal imaging in the emergency department (ED) from 1990 to 2009.MethodsWe retrospectively reviewed data on adult ED patients treated between 1990 and 2009 at our university-affiliated quaternary care institution. Examinations were coded by abdominal imaging modality: x-ray, sonography, CT, or MRI. Proportional costs for each imaging modality were evaluated using relative value units (RVUs). Chi-square tests were used to assess for significant trends.ResultsThe intensity of abdominal imaging per 1,000 ED visits increased 19.3% from 1990-2009 (p = 0.0050). The number of abdominal CT scans per 1,000 ED visits increased 17.5-fold (p < 0.0001). Similarly, the number of abdominal MRIs per 1,000 ED visits increased from 0 to 1.0 (p < 0.0001), and the number of abdominal sonographs per 1,000 ED visits increased 51.6% (p = 0.0198). However, the number of x-ray examinations per 1,000 ED visits decreased 81.6% (p < 0.0001). Abdominal imaging RVUs per 1,000 ED visits increased 2.7-fold (p < 0.0001), due primarily to CT imaging, which accounted for 14% of RVUs in 1990 and 76% of RVUs in 2009.ConclusionsThe intensity of abdominal imaging examinations per 1,000 ED visits and the number of abdominal imaging RVUs increased significantly over a 20-year period. CT replaced x-ray as the most common abdominal imaging modality for evaluation of ED patients. In light of these increasing costs as well as the increased radiation exposure of CT, clinical decision rules and computerized decision support may be needed to ensure appropriate utilization of abdominal CT in the ED.

Augmenting the Impact of Technology Adoption With Financial Incentive to Improve Radiology Report Signature Times

PURPOSE Radiology report signature time (ST) can be a substantial component of total report turnaround time. Poor turnaround time resulting from lengthy ST can adversely affect patient care. The combination of technology adoption with financial incentive was evaluated to determine if ST improvement can be augmented and sustained. METHODS This prospective study was performed at a 751-bed, urban, tertiary care adult teaching hospital. Test-site imaging volume approximated 48,000 examinations per month. The radiology department has 100 trainees and 124 attending radiologists serving multiple institutions. Over a study period of 4 years and 4 months, three interventions focused on radiologist signature performance were implemented: 1) a notification paging application that alerted radiologists when reports were ready for signature, 2) a picture archiving and communications systems (PACS)-integrated speech recognition report generation system, and 3) a departmental financial incentive to reward radiologists semiannually for ST performance. Signature time was compared before and after the interventions. Wilcoxon and linear regression statistical analyses were used to assess the significance of trends. RESULTS Technology adoption (paging plus speech recognition) reduced median ST from >5 to <1 hour (P < .001) and 80th-percentile ST from >24 to 15 to 18 hours (P < .001). Subsequent addition of a financial incentive further improved 80th-percentile ST to 4 to 8 hours (P < .001). The gains in median and 80th-percentile ST were sustained over the final 31 months of the study period. CONCLUSIONS Technology interventions coupled with financial incentive can result in synergistic and sustainable improvement in radiologist report-signing behavior. The addition of a financial incentive leads to better performance than that achievable through technology alone.

Inpatient Imaging Utilization: Trends of the Past Decade

OBJECTIVE We have previously reported inpatient imaging utilization trends at our institution from fiscal year (FY) 1984 through FY 2002. In this study, we assessed the trends in imaging utilization for inpatients from FY 2003 through FY 2012. MATERIALS AND METHODS In this institutional review board-approved retrospective study performed at a 793-bed tertiary care academic institution, we reviewed imaging utilization in adult inpatients from October 1, 2002, through September 30, 2012 (FY 2003 through FY 2012), and recorded the gross number of imaging studies coded by modality (conventional [radiography and fluoroscopy], ultrasound, nuclear medicine, CT, and MRI) and associated relative value units (RVUs). We used linear regression to assess trends in number of imaging studies and RVUs per case-mix-adjusted admission (CMAA). RESULTS The total number of imaging studies, as well as the number of CT, nuclear medicine, and conventional studies adjusted for case mix, decreased (p=0.02, p=0.0006, p=0.0008, and p=0.001, respectively); CT per CMAA increased until FY 2009 and then decreased through FY 2012. Utilization of ultrasound and MRI did not change significantly (p=0.15 and p=0.22, respectively). Unadjusted global RVUs increased until FY 2009 and then showed a slight decrease through FY 2012 (p=0.04), whereas RVUs per CMAA did not change significantly (p=0.18). CONCLUSION After decades of continued rise, imaging utilization for inpatients significantly decreased by most measures between FY 2009 and FY 2012. Future studies to evaluate the contribution of various factors to this decline, including efforts to reduce inappropriate use of imaging and concerns about potential harms of radiation exposure, may be helpful in optimizing imaging utilization and resource planning.

Radiology scheduling: preferences of users of radiologic services and impact on referral base and extension.

RATIONALE AND OBJECTIVES To study end-user attitudes and preferences with respect to radiology scheduling systems and to assess implications for retention and extension of the referral base. A study of the institutions historical data indicated reduced satisfaction with the process of patient scheduling in recent years. METHODS Sixty physicians who referred patients to a single, large academic radiology department received the survey. The survey was designed to identify (A) the preferred vehicle for patient scheduling (on-line versus telephone scheduling) and (B) whether ease of scheduling was a factor in physicians referring patients to other providers. Referring physicians were asked to forward the survey to any appropriate office staff member in case the latter scheduled appointments for patients. Users were asked to provide comments and suggestions for improvement. The statistical method used was the analysis of proportions. RESULTS Thirty-three responses were received, corresponding to a return rate of 55%. Twenty-six of the 33 respondents (78.8%, P < .01) stated they were willing to try an online scheduling system; 16 of which tried the system. Twelve of the 16 (75%, P < .05) preferred the on-line application to the telephone system, stating logistical simplification as the primary reason for preference. Three (18.75%) did not consider online scheduling to be more convenient than traditional telephone scheduling. One respondent did not indicate any preference. Eleven of 33 users (33.33%, P < .001) stated that they would change radiology service providers if expectations of scheduling ease are not met. CONCLUSION On-line scheduling applications are becoming the preferred scheduling vehicle. Augmenting their capabilities and availability can simplify the scheduling process, improve referring physician satisfaction, and provide a competitive advantage. Referrers are willing to change providers if scheduling expectations are not met.