Use Of Computed Tomographic Pulmonary Angiography Research Articles

Temporal Trends in the Use of Computed Tomographic Pulmonary Angiography for Suspected Pulmonary Embolism in the Emergency Department : A Retrospective Analysis.

Recently, validated clinical decision rules have been developed that avoid unnecessary use of computed tomographic pulmonary angiography (CTPA) in patients with suspected pulmonary embolism (PE) in the emergency department (ED). To measure any resulting change in CTPA use for suspected PE. Retrospective analysis. 26 European EDs in 6 countries. Patients with CTPA performed for suspected PE in the ED during the first 7 days of each odd month between January 2015 and December 2019. The primary end points were the CTPAs done for suspected PE in the ED and the number of PEs diagnosed in the ED each year adjusted to an annual census of 100 000 ED visits. Temporal trends were estimated using generalized linear mixed regression models. 8970 CTPAs were included (median age, 63 years; 56% female). Statistically significant temporal trends for more frequent use of CTPA (836 per 100000 ED visits in 2015 vs. 1112 in 2019; P<0.001), more diagnosed PEs (138 per 100000 in 2015 vs. 164 in 2019; P= 0.028), a higher proportion of low-risk PEs (annual percent change [APC], 13.8% [95% CI, 2.6% to 30.1%]) with more ambulatory management (APC, 19.3% [CI, 4.1% to 45.1%]), and a lower proportion of intensive care unit admissions (APC, -8.9% [CI, -17.1% to -0.3%]) were observed. Data were limited to 7 days every 2 months. Despite the recent validation of clinical decision rules to limit the use of CTPA, an increase in the CTPA rate along with more diagnosed PEs and especially low-risk PEs were instead observed. None specific for this study.

Discrepancies in the clinical and radiological profiles of COVID-19: A case-based discussion and review of literature.

The current gold standard for the diagnosis of coronavirus disease-19 (COVID-19) is a positive reverse transcriptase polymerase chain reaction (RT-PCR) test, on the background of clinical suspicion. However, RT-PCR has its limitations; this includes issues of low sensitivity, sampling errors and appropriate timing of specimen collection. As pulmonary involvement is the most common manifestation of severe COVID-19, early and appropriate lung imaging is important to aid diagnosis. However, gross discrepancies can occur between the clinical and imaging findings in patients with COVID-19, which can mislead clinicians in their decision making. Although chest X-ray (CXR) has a low sensitivity for the diagnosis of COVID-19 associated lung disease, especially in the earlier stages, a positive CXR increases the pre-test probability of COVID-19. CXR scoring systems have shown to be useful, such as the COVID-19 opacification rating score which helps to predict the need of tracheal intubation. Furthermore, artificial intelligence-based algorithms have also shown promise in differentiating COVID-19 pneumonia on CXR from other lung diseases. Although costlier than CXR, unenhanced computed tomographic (CT) chest scans have a higher sensitivity, but lesser specificity compared to RT-PCR for the diagnosis of COVID-19 pneumonia. A semi-quantitative CT scoring system has been shown to predict short-term mortality. The routine use of CT pulmonary angiography as a first-line imaging modality in patients with suspected COVID-19 is not justifiable due to the risk of contrast nephropathy. Scoring systems similar to those pioneered in CXR and CT can be used to effectively plan and manage hospital resources such as ventilators. Lung ultrasound is useful in the assessment of critically ill COVID-19 patients in the hands of an experienced operator. Moreover, it is a convenient tool to monitor disease progression, as it is cheap, non-invasive, easily accessible and easy to sterilise. Newer lung imaging modalities such as magnetic resonance imaging (MRI) for safe imaging among children, adolescents and pregnant women are rapidly evolving. Imaging modalities are also essential for evaluating the extra-pulmonary manifestations of COVID-19: these include cranial imaging with CT or MRI; cardiac imaging with ultrasonography (US), CT and MRI; and abdominal imaging with US or CT. This review critically analyses the utility of each imaging modality to empower clinicians to use them appropriately in the management of patients with COVID-19 infection.

Trends in Imaging for Suspected Pulmonary Embolism Across US Health Care Systems, 2004 to 2016

In response to calls to reduce unnecessary diagnostic testing with computed tomographic pulmonary angiography (CTPA) for suspected pulmonary embolism (PE), there have been growing efforts to create and implement decision rules for PE testing. It is unclear if the use of advanced imaging tests for PE has diminished over time. To assess the use of advanced imaging tests, including chest computed tomography (CT) (ie, all chest CT except for CTPA), CTPA, and ventilation-perfusion (V/Q) scan, for PE from 2004 to 2016. Cohort study of adults by age group (18-64 years and ≥65 years) enrolled in 7 US integrated and mixed-model health care systems. Joinpoint regression analysis was used to identify years with statistically significant changes in imaging rates and to calculate average annual percentage change (growth) from 2004 to 2007, 2008 to 2011, and 2012 to 2016. Analyses were conducted between June 11, 2019, and March 18, 2020. Rates of chest CT, CTPA, and V/Q scan by year and age, as well as annual change in rates over time. Overall, 3.6 to 4.8 million enrollees were included each year of the study, for a total of 52 343 517 person-years of follow-up data. Adults aged 18 to 64 years accounted for 42 223 712 person-years (80.7%) and those 65 years or older accounted for 10 119 805 person-years (19.3%). Female enrollees accounted for 27 712 571 person-years (52.9%). From 2004 and 2016, chest CT use increased by 66.3% (average annual growth, 4.4% per year), CTPA use increased by 450.0% (average annual growth, 16.3% per year), and V/Q scan use decreased by 47.1% (decreasing by 4.9% per year). The use of CTPA increased most rapidly from 2004 to 2006 (44.6% in those aged 18-64 years and 43.9% in those ≥65 years), with ongoing rapid growth from 2006 to 2010 (annual growth, 19.8% in those aged 18-64 years and 18.3% in those ≥65 years) and persistent but slower growth in the most recent years (annual growth, 4.3% in those aged 18-64 years and 3.0% in those ≥65 years from 2010 to 2016). The use of V/Q scanning decreased steadily since 2004. From 2004 to 2016, rates of chest CT and CTPA for suspected PE continued to increase among adults but at a slower pace in more contemporary years. Efforts to combat overuse have not been completely successful as reflected by ongoing growth, rather than decline, of chest CT use. Whether the observed imaging use was appropriate or was associated with improved patient outcomes is unknown.

Evaluating patients with pulmonarythromboembolism: a retrospective studyon the utilization of serum D-dimer assayand CT angiography

Background and objective: Serum D-dimer assay is an inexpensive laboratory test with a high negative predictive value, obviating the need for computed tomographic pulmonary angiography (CTPA) in patients with low clinical probability of thromboembolic disease. It has been recommended that CTPA may be performed only in patients with positive D-dimer assays and clinical suspicion of PTE (pulmonary thromboembolism), to curb unnecessary imaging and health care costs. We wanted to reassess the validity of this recommendation by looking into the D-dimer results in patients with positive PTE on CTPA. Methods: All patient records with positive PTE diagnosis on CTPA and having relevant laboratory data during one calendar year (January 01 to December 31, 2009) were selected. Serum D-dimer values of >500 ng/ml was considered abnormal. The D-dimer results among the patients who had the test performed were tabulated based on age and sex along with those without D-dimer assay in the same groups and correlated with their percentage distribution. Results: Out of a total of 98 positive PTE cases on CTPA, only 26 patients (26.5%) had a serum D-dimer assay done prior to CTPA. Of these, 20 (76.9%) had elevated values and 6 cases (23.1%) had a negative test. Negative D-dimer results varied with patient age, being highest in the 21-40 years age group. Conclusion: Overall, there seems to be more preferred use of CTPA and underutilization of serum D-dimer assay in clinical practice for suspected PTE. Secondly, negative D-dimer assay should not be used to triage patients with a high clinical index of suspicion for PTE.

Limited Hospital Variation in the Use and Yield of CT for Pulmonary Embolism in Patients Undergoing Total Hip or Total Knee Replacement Surgery.

Purpose To evaluate the variation among U.S. hospitals in overall use and yield of in-hospital computed tomographic (CT) pulmonary angiography (PA) in patients undergoing total hip replacement (THR) or total knee replacement (TKR) surgery. Materials and Methods Patients in the Premier Research Database who underwent elective TKR or THR between 2007 and 2011 were enrolled in this HIPAA-compliant, institutional review board-approved retrospective observational study. The informed consent requirement was waived. Hospitals were categorized into low, medium, and high tertiles of CT PA use to compare baseline patient- and hospital-level characteristics and pulmonary embolism (PE) positivity rates. To further investigate between-hospital variation in CT PA use, a hierarchical logistic regression model that included hospital-specific random effects and fixed patient- and hospital-level effects was used. The intraclass correlation coefficient (ICC) was used to measure the amount of variability in CT PA use attributable to between-hospital variation. Results The cohort included 205 198 patients discharged from 178 hospitals (median of 734.5 patients discharged per hospital; interquartile range, 316-1461 patients) with 3647 CT PA studies (1.8%). The crude frequency of CT PA scans among the hospitals ranged from 0% to 6.2% (median, 1.6%); more than 90% of the hospitals performed CT PA in less than 3% of their patients. The mean hospital-level PE positivity rate was 12.3% (median, 9.1%); there was no significant difference in PE positivity rate across low through high CT PA use tertiles (11.3%, 11.9%, 12.9%, P = .37). After adjustment for hospital- and patient-level factors, the remaining amount of interhospital variation was relatively low (ICC, 9.0%). Conclusion Limited interhospital variation in use and yield of in-hospital CT PA was observed among patients undergoing TKR or THR in the United States. © RSNA, 2016 Online supplemental material is available for this article.

Effectiveness of prognosticating pulmonary embolism using the ESC algorithm and the Bova score.

The prognostic value of the European Society of Cardiology (ESC) 2014 algorithm and the Bova score has lacked adequate validation. According to the ESC 2014 guidelines and the Bova score, we retrospectively risk stratified normotensive patients with PE who were enrolled in the PROTECT study. This study used a complicated course (which consisted of death from any cause, haemodynamic collapse, or recurrent PE) as the primary endpoint, and follow-up occurred through 30 days after the PE diagnosis. Of 848 patients, 37 % had a sPESI of 0 and 5 (1.6 %; 95 % confidence interval [CI], 0.5-3.7 %) experienced a complicated course. Of 143 patients with a sPESI of 0 points and negative computed tomographic pulmonary angiography (CTPA) for right ventricle (RV) dysfunction, three (2.1 %; 95 % CI, 0.4-6.0 %) experienced a complicated course. Four hundred seventy-eight (56 %) patients with a sPESI ≥ 1 had echocardiographic evidence of RV dysfunction or elevated troponin level or none, and 48 (10 %, 95 % CI, 7.5-13.1 %) experienced a complicated course. Fifty-seven (6.7 %) patients with a sPESI ≥ 1 had echocardiographic RV dysfunction and elevated troponin level, and 10 (17.5 %; 95 % CI, 8.8-29.9 %) experienced a complicated course, compared to 21.6 % (8 of 37 patients, 21.6 %; 95 % CI, 9.8-38.2 %) in Bova risk class III. In conclusion, the ESC 2014 prognostic algorithm is effective in the risk stratification of normotensive patients with PE. Use of CTPA did not improve the ability for identification of low-risk PE. Bova risk scoring did not significantly improve identification of intermediate-high risk PE.

Children Suspected of Having Pulmonary Embolism: Multidetector CT Pulmonary Angiography—Thromboembolic Risk Factors and Implications for Appropriate Use

To evaluate thromboembolic risk factors for pulmonary embolism (PE) detected by using computed tomographic (CT) pulmonary angiography in children and to determine whether such information could be used for more appropriate use of CT pulmonary angiography in this patient population. The institutional review board approved this HIPAA-compliant retrospective study and waived the need for patient informed consent. Two hundred twenty-seven consecutive CT pulmonary angiography studies in 227 pediatric patients who underwent CT pulmonary angiography for clinically suspected PE at a single large pediatric referral hospital between July 2004 and March 2011 were evaluated. Age, sex, referral setting, and D-dimer result, as well as seven possible risk factors, were compared between patients with and those without PE. Multiple logistic regression modeling was used to identify the independent risk factors of PE. Receiver operating characteristic curve analysis was applied to determine the optimal cutoff number of risk factors for predicting a positive CT pulmonary angiography result for PE in children. Thirty-six (16%) of 227 CT pulmonary angiography studies were positive for PE. Five risk factors, including immobilization (P < .001), hypercoagulable state (P = .003), excess estrogen state (P = .002), indwelling central venous line (P < .001), and prior PE and/or deep venous thrombosis (P < .001), were found to be significant independent risk factors for PE. With use of two or more risk factors as the clinical threshold, the sensitivity of a positive PE result was 89% (32 of 36 patients), and the specificity was 94% (180 of 191 patients). It is unlikely for CT pulmonary angiography results to be positive for PE in children with no thromboembolic risk factors. The use of risk factor assessment as a first-line triage tool has the potential to guide more appropriate use of CT pulmonary angiography in children, with associated reductions in radiation exposure and costs.

Computerized tomographic pulmonary angiography versus ventilation perfusion lung scanning for the diagnosis of pulmonary embolism

The purpose of this review is to focus on recent research that has addressed the relative merits of computed tomographic pulmonary angiography (CTPA) and ventilation perfusion (V/Q) scanning for the diagnosis of pulmonary embolism. Computed tomographic pulmonary angiography is the most sensitive test for the diagnosis of pulmonary embolism and its use has been associated with a rising incidence of the condition. Diagnostic algorithms using either CTPA or V/Q scanning have proven to be comparably safe to exclude the diagnosis of pulmonary embolism. Negative multidetector CTPA study results essentially ruled out the diagnosis of pulmonary embolism without the need to routinely exclude the presence of deep vein thrombosis. Use of multidetector CTPA was associated with significant radiation exposure that potentially increases risk of secondary malignancies. This is particularly a concern for young women given the risk of breast cancer. Single photon emission tomography (SPECT) V/Q and modified diagnostic criteria for V/Q scan interpretation increased their diagnostic accuracy compared with V/Q scanning and offer nuclear medicine modalities that are alternatives to CTPA in at least some patients with suspected pulmonary embolism at a fraction of the risk of radiation exposure. Excluding low risk patients for pulmonary embolism as defined by clinical scoring systems and D-dimer testing would enhance the yield of diagnostic testing. Computed tomographic pulmonary angiography is the most reliable test for diagnosis of pulmonary embolism. However, diagnostic algorithms using V/Q scanning are safe and may be preferred in some patient populations.

Impact of reliance on CT pulmonary angiography on diagnosis of pulmonary embolism: A Bayesian analysis

Spiral computed tomographic pulmonary angiography (CTPA) has become the primary test used to investigate suspected pulmonary embolism (PE) at many institutions, despite uncertainty regarding its sensitivity and specificity. Although CTPA-based diagnostic algorithms focus on minimizing the false-negative rate, we hypothesized that increasing use of CTPA also might lead to false-positive diagnoses. Determine the frequency of possible false-positive diagnoses of PE when CTPA is the primary diagnostic test. Retrospective cohort study. Two academic teaching hospitals. 322 patients with suspected PE evaluated with CTPA. We used a validated prediction rule to determine the pretest probability of PE in each patient. We combined these pretest probabilities with published estimates of CTPA test characteristics to generate expected posttest probabilities of PE. We compared these posttest probabilities to actual treatment decisions to determine the rate of false-positive diagnoses of PE. Among 322 patients investigated for PE, 37 (12%) had high pretest probability, 101 (32%) moderate, and 184 (57%) low. CT scans were interpreted as positive for PE in 57 patients (17.8%). Regardless of the pretest probability of PE, 96.5% of patients with a positive CTPA were treated with anticoagulants. Even under an optimistic assumption of CTPA test characteristics, as many as 25.4% of these patients may have been treated unnecessarily as a result of a false-positive diagnosis. Most of these patients had a low pretest probability of PE. Failure to utilize Bayesian reasoning when interpreting CTPA may lead to false-positive diagnoses of pulmonary embolism in a substantial proportion of patients.