Pulmonary embolism and lung scanning: cost-effectiveness and benefit:risk (original) (raw)
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Risk-Benefit Analysis of Pulmonary CT Angiography in Patients With Suspected Pulmonary Embolus
American Journal of Roentgenology, 2012
T examinations are the largest source of medical radiation exposure, accounting for 49% of collective effective medical radiation dose in 2006 [1]. In comparison with radiography, CT examinations are intrinsically high dose [2] and the increased x-ray power of MDCT scanners is associated with an increased average dose per examination [3], making it likely that an even higher radiation dose is currently delivered in centers with limited radiation dose awareness. CT dose reduction efforts have two components: The first is optimizing acquisition and reconstruction parameters to ensure that dose is as low as reasonably achievable and the second is ensuring that CT examinations are appropriately requested with adequate clinical justification. Clinical justification requires that the outcome
Ten years of imaging for pulmonary embolism: too many scans or the tip of an iceberg?
Clinical radiology, 2015
To examine the number and nature of investigations performed for suspected pulmonary embolism (PE) in a large teaching hospital and the change in incidence and severity of PE over a decade. In this retrospective study, all patients investigated for suspected PE using computed tomography pulmonary angiography (CTPA) or lung scintigraphy during 10 years to March 2012 were identified and their records reviewed. In the final year, all reportedly positive CTPA cases were reviewed and PE severity calculated, for comparison with similar historical data. From 2002 to 2012, total annual investigations for suspected acute PE increased by 163% (805 to 2121). CTPA increased by 325% (475 to 2019). Detection of PE increased by 121% (193 to 426 per annum), with stable distribution of severity scores. The positive scan rate decreased from 24% to 20%. The mean age of patients being investigated for PE increased from 56 to 63 years. Increased detection of PE is not due to disproportionate increase in...
Emergency Medicine Australasia, 2005
The aims of this study were to measure the: (i) effects of implementation of a new risk assessment strategy for patients with suspected pulmonary embolism (PE) on the use of imaging and D-dimer assay; (ii) negative predictive value for PE of a combination of low risk and negative D-dimer assay; and (iii) compliance of ED clinicians with the strategy. A non-randomized clinical trial was conducted in the ED of a 720-bed teaching hospital between November 2002 and August 2003. Study subjects with suspected PE were compared with 191 randomly selected historical controls. The risk assessment strategy of Kline et al. was disseminated and implemented. The negative predictive value for PE was 99% (95% confidence interval [CI] = 97-100%) in 114 patients with low risk and negative D-dimer. There was a 21% absolute reduction in the rate of imaging following the implementation of the risk assessment strategy (56% vs 77%, P < 0.001). Low risk combined with a negative D-dimer result may allow exclusion of PE without imaging.
Interventions to Reduce the Overuse of Imaging for Pulmonary Embolism: A Systematic Review
Journal of Hospital Medicine, 2018
Experimental and observational studies were included. The types of interventions, their efficacy and safety, the impact on healthcare costs, the facilitators, and barriers to their implementation were assessed. DATA SYNTHESIS: Seventeen studies were included assessing clinical decision support (CDS), educational interventions, performance and feedback reports (PFRs), and institutional policy. CDS impact was most comprehensively documented. It was associated with a reduction in imaging use, ranging from 8.3% to 25.4%, and an increase in diagnostic yield, ranging from 3.4% to 4.4%. The combined implementation of a CDS and PFR resulted in a modest but significant increase in the adherence to guidelines. Few studies appraised the safety of interventions. There was a lack of evidence concerning economic aspects, facilitators, and barriers. CONCLUSIONS: A combined implementation of an electronic CDS and PFRs is more effective than purely educational or policy interventions, although evidence is limited. Future studies of high-methodological quality would strengthen the evidence concerning their efficacy, safety, facilitators, and barriers.
Scanning Systems and Protocols Used During Imaging for Acute Pulmonary Embolism
Academic Radiology, 2006
Rationale and Objectives. The imaging systems and protocols used during ventilation-perfusion lung (V-P) scintigraphy and computed tomographic (CT) pulmonary angiography (CTPA) can affect diagnostic performance. We investigated the level of awareness of these factors among US clinicians who refer patients for imaging for suspected acute pulmonary embolism. Materials and Methods. Between September 2004 and February 2005, we conducted a mail survey of 855 physicians selected at random from three professional organizations. We asked participants how important the availability of state-ofthe-art equipment was in their imaging decisions, whether V-P scintigraphy was performed with planar or single-photon emission CT (SPECT) equipment in their communities, to identify the most advanced type of CT scanner used for CTPA, and whether CT venography (CTV) was performed routinely after CTPA. Results. We received completed surveys from 240 (29.8%) physicians practicing in 44 states. One hundred sixty-six respondents (70.9%) indicated that state-of-the-art equipment was an extremely or very important factor when they made imaging decisions. However, 191 clinicians (80.3%) did not know whether SPECT equipment was used for V-P scintigraphy, and 119 (50.6%) did not know the type of CT scanner used for CTPA in their communities. Of respondents, 39.2% reported access to multidetector row CT technology for CTPA, whereas 10.2% referred patients to facilities using singledetector CT. Only 9.3% of respondents indicated that CTV was performed routinely after CTPA. Conclusion. Although state-of-the-art equipment is important to them, clinicians practicing in the United States have limited knowledge of the equipment being used during CTPA and V-P scintigraphy scanning in their communities. Radiologists should intensify efforts to familiarize their clinical colleagues with the equipment they use.
European Journal of Nuclear Medicine and Molecular Imaging, 2003
Pulmonary embolism remains a challenging diagnostic problem. We developed a simple diagnostic strategy based on combination of assessment of the pretest probability with perfusion lung scan results to reduce the need for pulmonary angiography. We studied 390 consecutive patients (78% in-patients) with suspected pulmonary embolism. The pretest probability was rated low (<10%), intermediate (>10%, ≤50%), moderately high (>50%, ≤90%) or high (>90%) according to a structured clinical model. Perfusion lung scans were independently assigned to one of four categories: normal; nearnormal; abnormal, suggestive of pulmonary embolism (wedge-shaped perfusion defects); abnormal, not suggestive of pulmonary embolism (perfusion defects other than wedge shaped). Pulmonary embolism was diagnosed in patients with abnormal scans suggestive of pulmonary embolism and moderately high or high pretest probability. Patients with normal or near-normal scans and those with abnormal scans not suggestive of pulmonary embolism and low pretest probability were deemed not to have pulmonary embolism. All other patients were allocated to pulmonary angiography. Patients in whom pulmonary embolism was excluded were left untreated. All patients were followed up for 1 year. Pulmonary embolism was diagnosed non-invasively in 132 patients (34%), and excluded in 191 (49%). Pulmonary angiography was required in 67 patients (17%). The prevalence of pulmonary embolism was 41% (n=160). Patients in whom pulmonary embolism was excluded had a thrombo-embolic risk of 0.4% (95% confidence interval: 0.0%-2.8%). Our strategy permitted a non-invasive diagnosis or exclusion of pulmonary embolism in 83% of the cases (95% confidence interval: 79%-86%), and appeared to be safe.
Journal of Clinical Imaging Science, 2020
Objectives: Computed tomography pulmonary angiogram (CTPA) is one of the most commonly ordered and frequently overused tests. The purpose of this study was to evaluate the mean radiation dose to patients getting CTPA and to identify factors that are associated with higher dose. Material and Methods: This institutionally approved retrospective study included all patients who had a CTPA to rule out acute pulmonary embolism between 2016 and 2018 in a tertiary care center. Patient data (age, sex, body mass index [BMI], and patient location), CT scanner type, image reconstruction methodology, and radiation dose parameters (dose-length product [DLP]) were recorded. Effective dose estimates were obtained by multiplying DLP by conversion coefficient (0.014 mSv•mGy−1•cm−1). Multivariate logistic regression analysis was performed to determine the factors affecting the radiation dose. Results: There were 2342 patients (1099 men and 1243 women) with a mean age of 58.1 years (range 0.2–104.4 yea...
Journal of the American College of Radiology : JACR, 2018
To compare the proportion of emergency department (ED) patients who undergo subsequent chest CT or MR within 1 year of an initially negative scan for pulmonary embolism (PE). This single-center, retrospective, observational study examined the use of chest CT or MR for ED patients with MR angiography (MRA) negative for PE during April 2008 to March 2013. We compared the 1-year scan utilization for these cases to an age- and sex-matched cohort of patients who underwent CT angiography (CTA). We also calculated time to first follow-up scan and mean radiation dose in each arm. Trained data abstractors used a standardized protocol and electronic case report form to gather all outcomes of interest. Results are reported as means or proportions with their associated confidence intervals (CIs). In all, 717 ED patients (430 MRAs and 287 CTAs) were included. At 1 year, the proportion undergoing subsequent imaging (MRA 16.7%, CTA 15.3%; difference = 1.4%, 95% CI 4.05%-6.86%) and time to first fo...
Lung scanning in the diagnosis of pulmonary embolism: The emperor redressed
Seminars in Nuclear Medicine, 1991
Diagnosis and management of the patient with pulmonary embolism remains a vexing clinical problem. Emboli are often unsuspected clinically. Ventilationperfusion (VQ) scintigraphy is known to miss some emboli found on pulmonary angiography. Some physicians recommend diagnostic approaches in which the lung scan plays a relatively minor role, and angiography is required for many patients. Major prospective studies recently have made available objective data for formulation and evaluation of diagnostic and therapeutic strategies. These data suggest that the lung scan is a better predictor of patient outcome than has been previously appreciated. The goal of V/Q scanning is not detection of pulmonary emboli per se, but rather the identification of patients at a high or low risk for future embolic events if they are not anticoagulated.