Computed Tomography Pulmonary Angiography Research Articles

Pulmonary Arteriovenous Malformation in a Young Man

ABSTRACT A young man was diagnosed to have pulmonary arteriovenous malformation (PAVM) when he was admitted with COVID infection. He had no respiratory distress but his saturation at room air was 90%. Chest X-ray revealed non-homogenous opacity in left lower lobe (LLL). The heart was structurally normal on 2D echocardiography; the saline bubble study was however positive for extra-cardiac shunt. Computed tomography pulmonary angiography (CTPA) revealed PAVM with well-defined lobulated sac measuring 2.9 × 1.9 × 2.5 cm in lateral basal segment of LLL with segmental branch of left pulmonary artery as feeder vessel and it drained into left pulmonary vein. The patient was managed with percutaneous intervention using Amplatzer Vascular Plug II to occlude the feeder vessel. Post-intervention, patient’s saturation improved to 98% at room air and saline bubble study was negative for extra-cardiac shunt. CTPA at 06 weeks revealed complete thrombosis of the sac.

Pulmonary Embolism Risk Assessment in Acute Isolated Distal Deep Venous Thrombosis.

The clinical risk factors and risk of developing pulmonary embolism (PE) in patients with acute isolated distal deep venous thrombosis (IDDVT) were assessed using single complete-duplex ultrasound (CDUS) imaging to reduce over-testing and over-treatment. This observational study was conducted from January 2020 to December 2022. Retrospective analysis was performed on CT pulmonary angiography (CTPA), blood coagulation markers, myocardial injury markers, blood gas analysis, and CDUS imaging of the lower extremity blood vessels of 146 patients with newly diagnosed IDDVT. Binary logistic regression was used to evaluate the relationship between these indicators and PE. After stepwise regression analysis, the predictors included in the regression model were D-dimer (DD), the sum of the thrombus length, and the maximum value of the thrombus width, with odds ratios (ORs) of 1.307 (p <0.001), 1.018 (p = 0.005), and 1.613 (p = 0.018), respectively. The combined prediction model achieved an area under the receiver operating characteristic curve (AUC) of 0.832 [95% confidence interval (CI): 0.761, 0.902]. By balancing the sensitivity and specificity of DD, combined single CDUS improves the predictive value for PE in patients with IDDVT. Key Words: Venous thrombosis, Pulmonary embolism, Ultrasonography, D-dimer, Diagnosis.

Comparison of Qanadli score with conventional risk stratifiers in non-massive pulmonary emboli.

The management and risk stratification of non-massive pulmonary embolism (PE) remain unclear. However, early assessment of PE severity can aid physicians in establishing better treatment milestones. There has been no direct comparison of mortality rates in patients with non-massive PE, and existing data are sometimes contradictory. Therefore, we examined the relationship between the Qanadli index and conventional risk stratifiers in PE. We retrospectively analyzed 200 consecutively selected patients diagnosed with PE. The assessment included computed tomography pulmonary angiography, electrocardiography, echocardiography findings, outcomes, and a comparison with the Simplified Pulmonary Embolism Severity Index (SPESI) score. Descriptive, regression, and receiver operating characteristic analyses were performed. The mean Qanadli score was 13.5 ± 1.15. Pearson correlation analysis revealed significant associations between the total Qanadli score and several variables: right ventricular enlargement, follow-up ejection fraction, and SPESI score. Although the Qanadli score did not significantly predict mortality, the risk of death increased by 58.8% for each 1-unit increase in the SPESI score. Although the Qanadli index is valuable in assessing PE and guiding treatment strategies, its standalone predictive value for mortality may be insufficient. Therefore, incorporating scoring systems such as the SPESI and echocardiographic findings is recommended for more accurate mortality prediction.

Optimised CT Pulmonary angiography in pregnant women - first line or last resort?

Optimised CT Pulmonary angiography in pregnant women - first line or last resort?

Simultaneous high-pitch multi-energy CT pulmonary angiography using a dual-source photon-counting-detector CT: A phantom experiment.

A dual-source CT system can be operated in a high-pitch helical mode to provide a temporal resolution of 66ms, which reduces motion artifacts in CT pulmonary angiography (CTPA). It can also be operated in a multi-energy (ME) mode to provide iodine maps, beneficial in the evaluation of pulmonary embolism (PE). No energy-integrating detector (EID) CT can perform simultaneous ME and high-pitch acquisition. This phantom study aimed to evaluate the ability of a photon-counting-detector (PCD) CT to perform simultaneous high-pitch and ME imaging for CTPA. A motion phantom was used to mimic the respiratory motion. Two tubes filled with iodine with intravascular thrombus mimicked by injecting glue within the tubes were placed along with 5, 10, and 15mg/mL iodine samples, on a motion phantom at 20 and 30 revolutions per minute. Separate high-pitch and ME EID-CT scans and a single high-pitch ME PCD scan were acquired and virtual monoenergetic images and iodine maps reconstructed. Percent thrombus occlusion was measured and compared between static and moving images. When there was motion, EID-CT ME suffered from significant motion artifacts. The measured iodine concentrations with PCD-CT in high-pitch ME were more stable when there was a motion, with a lower standard deviation than EID-CT in ME mode. The estimated percent thrombus occlusion dropped significantly with applied motion on EID-CT, while PCD-CT high-pitch ME mode showed good agreement between measurements on static or moving images. PCD-CT with combined ME and high-pitch mode facilitates simultaneous accurate iodine quantification and assessment of intravascular occlusion.

Precision in Pulmonary Embolism Diagnosis: Leveraging D-dimer Levels With Computed Tomography Pulmonary Angiography (CTPA) Insights.

Introduction Pulmonary embolism (PE) remains a critical condition requiring timely diagnosis and treatment. The use of D-dimer, a fibrin degradation product, as a biomarker, combined with computed tomography pulmonary angiography (CTPA), is a common practice in diagnosing PE. Aim This study aims to increase diagnostic accuracy for PE by relating the D-dimer levels to the findings on CTPA. Specifically, it aimsto calculate the sensitivity and specificity of D-dimer levels against CTPA results and also establish the association of D-dimer levels with the location of the PE. Methods This retrospective analysis was conducted at a tertiary care hospital, including patients who underwent CTPA and had D-dimer levels recorded over a one-year period. The total sample size was 124. D-dimer levels were categorized into four groups based on CTPA findings: Category 0 (no PE), Category I (peripheral PE), Category II (PE in lobar arteries), and Category III (central embolisms in the pulmonary trunk or arteries). Statistical analyses were performed to evaluate the correlation between D-dimer levels and CTPA findings, including sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). Results The study found that Category 0 (no PE) had an average D-dimer of 3.6 mg/L, Category I (peripheral PE) had 4.3 mg/L, Category II (PE in lobar arteries) had 3.6 mg/L, and Category III (central embolisms) had 7.1 mg/L. The sensitivity of D-dimer in predicting PE was 1.0, and the specificity was 0.2. The PPVwas 0.3208, and the NPVwas 1.0. These findings indicate a significant correlation between elevated D-dimer levels and the presence of PE. Conclusion Integrating D-dimer levels with CTPA findings can improve diagnostic accuracy and efficiency for PE. Establishing reliable D-dimer cutoff values may help clinicians better stratify patient risk and make informed decisions about the need for imaging, thereby optimizing resource utilization and minimizing unnecessary CTPA scans. This study highlights the potential benefits of combining biomarker analysis with imaging results in the clinical management of PE.

Diagnostic management of acute pulmonary embolism

Straightforward, accurate diagnostic management in patients presenting with clinically suspected pulmonary embolism (PE) is essential, since starting anticoagulant treatment may give important adverse effects of bleeding, while false exclusion of the disease may lead to recurrent VTE, with associated morbidity and mortality. In the past three decades, considerable improvement in the diagnostic management of PE has been made. Computed tomography pulmonary angiography (CTPA) has largely replaced conventional pulmonary angiography and ventilation-perfusion lung scanning as the imaging methods of choice. Several diagnostic algorithms, all able to minimize the need for radiological imaging have been developed and validated. Lastly, within the diagnostic algorithms, varying D-dimer cut-off levels have successfully been introduced to further downsize the need for radiological imaging.

Cardiogenic shock secondary to immune checkpoint inhibitor associated myocarditis.

Immune checkpoint inhibitors have transformed the treatment for multiple cancers and are increasingly used in recent years, but they can cause potentially life-threatening cardiac toxicity. We report a case of a 64-year-old gentleman who presented to the Emergency Department with symptoms of fatigue and breathlessness whilst receiving treatment with an immune checkpoint inhibitor, pembrolizumab, for cholangiocarcinoma. He was found to be in cardiogenic shock with an abnormal electrocardiogram and elevated cardiac troponin at presentation. Echocardiogram demonstrated severely impaired right and left ventricular function. Computed tomography pulmonary angiography and invasive coronary angiography excluded pulmonary embolism and acute myocardial infarction, respectively, and he was diagnosed with immune checkpoint inhibitor associated myocarditis. He was treated with high-dose methylprednisolone and a dobutamine infusion. Within days, his troponin and C-reactive protein levels decreased, and his left ventricular function improved. He was established on heart failure therapies and discharged from hospital 12 days later.

Enhancing Pulmonary Embolism Detection in COVID-19 Patients Through Advanced Deep Learning Techniques.

The intersection of COVID-19 and pulmonary embolism (PE) has posed unprecedented challenges in medical diagnostics. The critical nature of PE and its increased incidence during the pandemic underline the need for improved detection methods. This study evaluates the effectiveness of advanced deep learning techniques in enhancing PE detection in post-COVID-19 patients through Computed Tomography Pulmonary Angiography (CTPA) scans. Using a dataset of 746 anonymized CTPA images from 25 patients, we fine-tuned the state-of-the-art Ultralytics YOLOv8 object detection model, which was trained on 676 images with 1,517 annotated bounding boxes and validated on 70 images with 108 bounding boxes. After 200 epochs of training, which lasted approximately 1.021 hours, the YOLOv8 model demonstrated significant diagnostic proficiency, achieving a mean Average Precision (mAP) of 0.683 at an IoU threshold of 0.50 and a mAP of 0.246 at the IoU range of 0.50:0.95 in the validation dataset. Notably, the model reached a maximum precision of 0.85949 and a maximum recall of 0.81481, though these metrics were observed in separate epochs. These findings emphasize the model's potential for high diagnostic accuracy and offer a promising direction for deploying AI tools in clinical settings, significantly contributing to healthcare innovation and patient care post-pandemic.

Improved Pulmonary Artery Evaluation Using High-Pitch Photon-Counting CT Compared to High-Pitch Conventional or Routine-Pitch Conventional Dual-Energy CT.

Pulmonary CT angiography (CTA) to detect pulmonary emboli can be performed using conventional dual-source CT with single-energy acquisition at high-pitch (high-pitch conventional CT), which minimizes motion artifacts, or routine-pitch, dual-energy acquisitions (routine-pitch conventional DECT), which maximize iodine signal. We compared iodine signal, radiation dose, and motion artifacts of pulmonary CTA between these conventional CT modalities and dual-source photon-counting detector CT with high-pitch, multienergy acquisitions (high-pitch photon-counting CT). Consecutive clinically indicated pulmonary CTA exams were collected. CT number/noise was measured from the main to right lower lobe segmental pulmonary arteries using 120 kV threshold low, 120 kV, and mixed kV (0.6 linear blend) images. Three radiologists reviewed anonymized, randomized exams, rating them using a 4- or 5-point Likert scale (1 = worst, and 4/5 = best) for contrast enhancement in pulmonary arteries, motion artifacts in aortic root to subsegmental pulmonary arteries, lung image quality; pulmonary blood volume (PBV) map image quality (for multienergy or dual-energy exams), and contribution to reader confidence. One hundred fifty patients underwent high-pitch photon-counting CT (n = 50), high-pitch conventional CT (n = 50), and routine-pitch conventional DECT (n = 50). High-pitch photon-counting CT had lower radiation dose (CTDIvol: 8.1 ± 2.5 vs 9.6 ± 6.8 and 16.2 ± 8.5 mGy, respectively; P < 0.001), and routine-pitch conventional DECT had significantly less contrast (P < 0.009). CT number and CNR measurements were significantly greater at high-pitch photon-counting CT (P < 0.001). Across readers, high-pitch photon-counting CT demonstrated significantly higher subjective contrast enhancement in the pulmonary arteries compared to the other modalities (4.7 ± 0.6 vs 4.4 ± 0.7 vs 4.3 ± 0.7; P = 0.011) and lung image quality (3.4 ± 0.5 vs 3.1 ± 0.5 vs 3.1 ± 0.5; P = 0.013). High-pitch photon-counting CT and high-pitch conventional CT had fewer motion artifacts at all levels compared to DECT (P < 0.001). High-pitch photon-counting CT PBV maps had superior image quality (P < 0.001) and contribution to reader confidence (P < 0.001) compared to routine-pitch conventional DECT. High-pitch photon-counting pulmonary CTA demonstrated higher contrast in pulmonary arteries at lower radiation doses with improved lung image quality and fewer motion artifacts compared to high-pitch conventional CT and routine-pitch conventional dual-energy CT.

T Wave Inversion: A Screening Tool for Rapidly Differentiating Acute Coronary Syndrome and Pulmonary Embolism.

Introduction Acute coronary syndrome (ACS) and acute pulmonary embolism (PE) are life-threatening conditions with similar clinical presentations. As current diagnostic tools, such as computed tomography pulmonary angiography, for distinguishing between these two conditions are time-consuming and may not be available in all settings, we tried in this study to devise a diagnostic tool based on electrocardiography to distinguish between ACS and acute PE based on T wave features. Methods Medical records of patients with diagnoses of ACS and acute PE, who were referred to three hospitals affiliated with Shiraz University of Medical Sciences, Shiraz, Iran, from March 2019 to March 2021, were evaluated. One expert cardiologist read patients' electrocardiograms (ECGs). All ECGs were recorded at the standard 25 mm/s and 10 mm/mV. The sum of T wave inversion or TWI (mV) in consecutive leads, including anterior leads (V1, V2, V3, and V4), inferior leads (II, III, aVF), and lateral leads (I, aVL, V5, and V6) were calculated to estimate the cut-off points used to differentiate ACS versus acute PE. The receiver operating characteristic (ROC) curve was used to estimate the diagnostic accuracy of T wave changes. The Youden index was used to calculate the optimum cut-offs for sensitivity and specificity. Results Of 151 patients with a mean age of 55.44±12.88 years, 74 were in the acute PEand 77 were in the ACS groups. The results showed that the TWI sum in anterior leads >1.2 mV (P<0.001), in lateral leads >0.9 mV (P<0.001), in anterior-to-inferior leads ratio >12 (P<0.001), and V4/V1 leads ratio >4 (P<0.001) rules out acute PE. Anterior-to-lateral TWI ratio (AUC=0.807, sensitivity=70.3%, specificity=10%) was significantly distinctive among ACS and acute PE patients. Conclusion TWI sum in anterior leads >1.2 mV, in lateral leads >0.9 mV, in anterior-to-inferior leads ratio >12, and in V4/V1 leads ratio >4 rules out acute PE. The anterior-to-lateral TWI ratio obtained from patients' ECG was significantly distinctive among the patients and can be used as a screening tool.

Prevalence of pulmonary embolism among post COVID-19 patients underwent CT pulmonary angiography, in comparison to others

Prevalence of pulmonary embolism among post COVID-19 patients underwent CT pulmonary angiography, in comparison to others

CT Imaging Findings of Pulmonary Artery Stenosis: A Pictorial Review.

Pulmonary artery stenosis represents a group of disorders involving main, branch or peripheral pulmonary arteries with pain, dyspnea, hemoptysis or even no symptoms. Early diagnosis and timely intervention are crucial for reducing mortality, but timely diagnosis is challenging due to the non-specific symptoms. Computed tomography pulmonary angiography (CTPA) is useful in the diagnosis because it can provide more details about abnormal changes in the lumen, vessel wall and adjacent mediastinal structures. Congenital and acquired pulmonary artery anomalies have some characteristics on CTPA, which can be useful for differential diagnosis. Awareness of these conditions is important for radiologists. This pictorial review provides an overview of CTPA imaging features of pulmonary artery stenosis.

Unlocking the power of echocardiography: strategies in risk stratification of patients with PE using echocardiography

Objectives: Pulmonary embolism (PE) is challenging to diagnose due to nonspecific symptoms. While computed tomography pulmonary angiography (CTPA) is the gold standard, transthoracic echocardiography (TTE) is frequently used first. This study aimed to evaluate the accuracy of TTE findings in predicting the severity of CTPA-confirmed PE. Methods: This retrospective study in 2023, analyzed 124 patients who underwent CTPA for suspected PE at Seyed Al Shohada Hospital of Urmia, Iran. The Pulmonary Embolism Severity Index (PESI), as a risk stratification tool for pulmonary embolism, was measured in the first hours of hospitalization. TTE was performed 48 hours following hospital admission, with an emphasis on Key TTE parameters, including McConnell’s sign, D-shape septum sign, right ventricular (RV) dimensions, left ventricular dimensions, pulmonary artery (PA) diameter, tricuspid regurgitation gradient (TRG), Tricuspid annular plane systolic excursion (TAPSE) and PA acceleration time (PaACT). Sensitivity, specificity and predictive value were all calculated. Results: Most patients were women (53.23%) over 60 (38.71%). Several TTE measures showed promise for predicting PE: RV dilation (sensitivity 84%, specificity 77%), PA diameter (84% and 28%), TRG (66% and 58%), and PA acceleration time (92% and 62%). However, McConnell’s sign had low accuracy (area under ROC curve 0.62). Tricuspid annular plane systolic excursion (TAPSE) and PA acceleration time showed the best predictive performance (AUC 0.95-0.92) and can be used as screening tools for life-threatening massive PE.PESI index test, when compared to the gold standard CT scan (which shows lung involvement), does not provide additional valuable information and accurate predictions about the severity of PE. Conclusions: TAPSE and PaACT showed excellent predictive ability to CTPA-detected PE. RV dilation and PA diameter also showed good predictive capability. Findings support using some TTE indices to screen for PE severity and risk assessment before CTPA when access is limited.

Unsupervised physics-informed deep learning for assessing pulmonary artery hemodynamics

Deep learning advancements have significantly benefited medical applications. One such helpful application is noninvasive fractional flow reserve (FFR) evaluation along the pulmonary artery tree, which aids in planning optimal balloon pulmonary angioplasty. This study proposes a surrogate model that employs an unsupervised physics-informed neural network (UPNN) to predict FFR based on pulmonary CT angiography. To ensure the UPNN strictly follows the unique solution of the governing equations, we implemented a hard boundary conditions enforcement approach. Subsequently, a finite difference convolutional filter was developed to enhance connectivity among neighboring points. This allows the neural networks to propagate boundary conditions into the unseen vessel interior and perceive the geometric structure of the computational domain. We also introduced regularization constraints on the three components contributing to pressure drop within the artery tree. A total of 4500 synthetic pulmonary artery trees were used to train the UPNN with impedance outlet boundary conditions. We found that the limits of agreement of FFR trained by UPNN ranged from −0.05 to 0.04 with computational fluid dynamics (CFD) simulation results. The testing results showed that the correlation coefficient between FFR predicted by UPNN and CFD were 96.1% and 94.7% for synthetic and patient-specific data, respectively. Using invasive FFR as reference, the accuracy of FFR predicted by UPNN and CFD was 81.4% and 84.8%, respectively. These results demonstrate that our UPNN-based surrogate model’s performance in evaluating FFR aligns closely with CFD simulations.

Uncommon threads: pneumopericardium complexity following liver catheter removal in pancreatic cancer

Pneumopericardium, the presence of air within the pericardial sac, is a rare but critical condition that can lead to severe complications such as tension pneumopericardium and cardiac tamponade, causing hemodynamic instability and necessitating immediate intervention. Various etiologies include congenital defects, post-surgical complications, infections, and trauma. Malignancies, such as advanced esophageal cancer or lung carcinoma, can also cause pneumopericardium via fistula formation. Multimodal imaging, including chest X-ray, echocardiography, and computed tomography (CT), is essential for diagnosis. This case report discusses a 65-year-old male with advanced pancreatic adenocarcinoma who developed pneumopericardium following the removal of a left lobe liver drainage catheter. Initial CT imaging revealed liver lesions suspicious for metastatic disease or abscess, leading to drainage procedures. Following the removal of the drainage tube, the patient experienced respiratory distress and hypotension, and computed tomography pulmonary angiogram (CTPA) revealed pneumopericardium, likely due to a fistula formed between the abscess and pericardium. Despite no echocardiographic signs of tamponade, the patient’s persistent hypotension warranted CT-guided pericardiocentesis, resulting in gradual blood pressure improvement. This case highlights the intricate interplay between malignancy, infection, and procedural complications in developing pneumopericardium. It emphasizes the need for a multidisciplinary approach and the importance of considering both the quantity and rate of air accumulation when assessing the risk of hemodynamic compromise. The patient’s hemodynamic instability and subsequent improvement following pericardiocentesis underscore the critical role of timely intervention in managing this condition.

The prevention, diagnosis and management of pregnancy-associated pulmonary embolism

Pregnancy-associated pulmonary embolism (PE) is a type of venous thromboembolism (VTE) that seriously threatens the lives of pregnant women and has gained more attention in clinical practice. Due to physiological and anatomical characteristics, the incidence of VTE during pregnancy and postpartum is significantly higher than that during non-pregnancy periods. Currently, guidelines widely acknowledge the exploration of appropriate risk assessment models to evaluate the risk of pregnancy-associated VTE and to take corresponding preventive measures from mechanical to medication methods according to different risk levels. For patients suspected of PE, initial assessments can be made based on whether they exhibit clinical manifestations of deep vein thrombosis, with options including vascular compression ultrasonography or chest X-ray examination. Confirmation relies on CT pulmonary angiography or V/Q imaging. For patients with shock, echocardiography can be quickly used for the diagnosis and differential diagnosis of PE. The management of pregnancy-associated pulmonary embolism PE depends on the patient's hemodynamic status, with options including reperfusion therapy or anticoagulation therapy. Extracorporeal membrane oxygenation may also be beneficial in high risk patients. The overall evidence level for the prevention and management of pregnancy-associated PE is low, and further exploration in clinical practice is still needed to promote the safety of pregnant women.

Incidence of fatal and non-fatal pulmonary thromboembolism after removal of tunnelled central venous haemodialysis catheters without ultrasound scan and anticoagulation.

Catheter related thrombosis is a common complication of tunnelled central venous catheter (TCVC) usage. There are concerns that TCVC removal could dislodge a thrombus to cause pulmonary thromboembolism (PE). The incidence of PE following TCVC removal is unclear and so the aim of this study was to investigate the incidence of PE and whether it is high enough to warrant screening with ultrasound with a view to systemic anticoagulation prior to TCVC removal. 1102 consecutive TCVC removals without ultrasound and systemic anticoagulation were included in this retrospective study. Data were extracted from electronic health records. Measures to identify PE events included: deaths, computed tomography pulmonary angiogram (CT-PA), isotope lung perfusion scans and D-dimers blood tests within 7 days of removal. Of the 1102 TCVC removals, the mean age of patients was 56.9 years and 57.3% were male. The primary renal diagnosis for 24.5% of patients was diabetic nephropathy. There were seven deaths following removal, none of which had PE as a contributing cause on review of their clinical history and death certificates. Five CT-PAs and one isotope lung perfusion scan were carried out in the 7 days after TCVC removal and none had a positive finding of PE. Three patient had D-dimers measured in blood within 7 days and none of these patients were subsequently diagnosed with PE. There was no evidence of fatal or non-fatal PE's occurring in the 7 days following TCVC removal. This would support the practice of removing TCVCs without the need for ultrasound screening and without a period of systemic anticoagulation.

An abysmal conundrum associated with a misplaced dialysis catheter.

A 25-year-old female patient with chronic glomerulonephritis, initiated on haemodialysis presented with high-grade fever, a dysfunctional catheter, low oxygen saturation and unstable blood pressure. Upon evaluation, the patient was febrile with elevated white blood cell counts. She was intubated, started on inotropes and transferred to the intensive care unit. Chest radiography showed that the tunnelled internal jugular dialysis catheter had migrated to the inferior vena cava. Echocardiography and transoesophageal echocardiography showed severe heart dysfunction with a large thrombus attached to the catheter, indicating catheter-related atrial thrombus (CRAT). CT pulmonary angiography revealed blockage of the segmental pulmonary arteries, suggesting pulmonary embolism. Blood and tracheal cultures revealed Methicillin-resistant Staphylococcus aureus (MRSA). The patient was administered appropriate antibiotics and anticoagulants and underwent surgical removal of the thrombus and the catheter. This case demonstrates the risks associated with improper placement of dialysis catheters and highlights the brief management of CRAT.

CT Pulmonary Angiogram Clinical Pretest Probability Tool: Impact on Emergency Department Utilization

ObjectiveCurrently, computed tomographic pulmonary angiogram (CTPA) for evaluating acute pulmonary embolism (PE) in Emergency Departments (EDs) is overused and with low yields. The goal of this study is to assess the impact of an evidence-based clinical decision support (CDS) tool, aimed at optimizing appropriate use of CTPA for evaluating PE. MethodsThe study was performed at EDs in a large healthcare system and included 9 academic and community hospitals. The primary outcome was the percent difference in utilization (number of CTPA performed/number of ED visits) and secondary outcome was yield (percentage of CTPA positive for acute PE), comparing 12 months before (6/1/2021-5/31/2022) vs. 12 months after (6/1/2022-5/31/2023) a system-wide implementation of the CDS. Univariate and multivariable analyses using logistic regression were performed to assess factors associated with diagnosis of acute PE. Statistical process control (SPC) charts were used to assess monthly trends in utilization and yield. ResultsAmong 931,677 visits to Emergency Departments, 28,101 CTPAs were performed on 24,675 patients. 14,825 CTPAs were performed among 455,038 visits (3.26%) pre-intervention; 13,276 among 476,639 visits (2.79%) post-intervention, a 14.51% relative decrease in CTPA utilization (chi-square, p<0.001). CTPA yield remained unchanged (1371/14825=9.25% pre- vs. 1184/13276=8.92% post-intervention; chi-square, p=0.34). Patients with COVID diagnosis prior to CTPA had higher probability of acute PE. SPC charts demonstrated seasonal variation in utilization (Friedman test, p=0.047). DiscussionImplementing a CDS based on validated decision rules was associated with a significant reduction in CTPA utilization. The change was immediate and sustained for 12 months post-intervention.