Emerg Radiol DOI 10.1007/s10140-014-1265-6
Variation in the utilization and positivity rates of CT pulmonary angiography among emergency physicians at a tertiary academic emergency department Yingming Amy Chen & Bruce G. Gray & Glen Bandiera & David MacKinnon & Djeven P. Deva
Received: 10 July 2014 / Accepted: 27 August 2014 # American Society of Emergency Radiology 2014
Abstract We examined the patient and physician characteristics related to the use and yield of computed tomography pulmonary angiogram (CTPA) for the diagnosis of pulmonary embolism (PE) at a tertiary academic hospital emergency department (ED). A cross-sectional retrospective study was conducted on 835 consecutive ED patients with suspected PE who underwent CTPA. Radiology report data were extracted from our institution’s RIS PACS software (Syngo Imaging, Siemens) based on a targeted search of all CTPA reports from 2010 to 2012. Utilization and PE positivity rates of CTPA were calculated and correlated with patient characteristics including age and gender, as well as emergency physician (EP) characteristics including gender, years in practice, and training certification. Acute PE was diagnosed in 17.8 % of patients. A further 32.9 % of the scans were negative for PE but had other clinically significant findings. We found higher utilization rates in female and older patients (p0.15 with cut-offs at 5, 10, and 20 years post-residency), gender (p=0.59), or training certification (p=0.56 between EPs certified by the 5-year program of the Royal College of Physicians of Canada versus the 3year program of the College of Family Physicians of Canada). Y. A. Chen (*) : B. Gray : D. P. Deva Department of Medical Imaging, St. Michael’s Hospital, 30 Bond Street, 3rd Floor Cardinal Carter Wing, Toronto, Ontario, Canada M5B 1W8 e-mail: [email protected]
G. Bandiera : D. MacKinnon Department of Emergency Medicine, St. Michael’s Hospital, Toronto, Ontario, Canada
Our study demonstrated considerable inter-physician variability in the utilization and PE positivity rates of CTPA. These results suggest an opportunity for a more standardized approach to the use of CTPA among EPs at our institution. Keywords CT pulmonary angiogram . Pulmonary embolism . Test utilization . Inter-physician variation
Introduction Computed tomography CT pulmonary angiogram (CTPA) has become the imaging test of choice in emergency department patients suspected of pulmonary embolism (PE). Its use has dramatically increased in the last decade , due to the widespread availability of multidetector CT, combined with CTPA’s high sensitivity and accuracy compared to ventilationperfusion scintigraphy and conventional pulmonary angiography in the diagnosis of PE [2–5]. However, CTPA is not without its risks, including radiation exposure, contrast nephrotoxicity and allergy, as well as high cost to the health care system. Clinical guidelines have been developed in recent years to aid in deciding when to use CTPA . However, despite the implementation of such guidelines, both utilization and diagnostic yield rates vary considerably across published data, suggesting likely overuse in some settings and underuse in others [7, 8]. The patient and physician characteristics related to CTPA use have not been well explored. Although PE incidence rates among different genders and age cohorts undergoing CTPA have been previously reported and compared [9, 10], CTPA utilization rates in these cohorts remain unknown. Furthermore, only one previous study has examined the interphysician variability in the use of CTPA , with no specific data on the potential relationships between utilization and physician characteristics. Such relationships have been explored in many other types of test ordering .
Therefore, the purpose of our study is twofold. First, we sought to determine the utilization and PE diagnosis rate of CTPA among different patient age and gender groups in a tertiary academic emergency department (ED). Second, we sought to examine the inter-physician variation in CTPA use at our institution and correlate these metrics to physician characteristics including years in practice, gender, and training certification.
CT imaging technique The CTPA examinations were performed on a 64-slice GE LightSpeed VCT scanner. The PE protocol involved 0.625 mm collimation for a 10 to 15-s breath-hold from the thoracic inlet to the upper abdomen at 120 kV. Automatic real time tube current modulation varied the current milliampere (mA) according to the patient’s body habitus. Approximately 100 mL of Iodixanol contrast (GE Healthcare) was injected at 5 mL/s into an antecubital vein, with the scan initiated by manual triggering based on visual assessment of contrast arrival in the main pulmonary artery. Studies were interpreted on 1.25 mm reconstructions.
Study population Outcome measures Our ED is located in a tertiary academic hospital in a large metropolitan area and receives approximately 60,000 visits per year. All of our attending physicians are certified in Emergency Medicine (EM), either through the 3-year Canadian College of Family Physicians Certificate of Special Competence in Emergency Medicine (CCFP (EM)) or the 5-year Fellowship of the Royal College of Physicians (FRCP) in Emergency Medicine. All emergency physicians (EPs) working in the ED were initially considered for inclusion in the study. The number of patients seen by individual EPs over the 3-year study period was obtained to normalize the number of CTPA studies ordered by each EP. EPs who saw