The role of computed tomography in the diagnosis of acute and chronic pulmonary embolism

Investigation in image quality and immediate patient safety using pre-dual-flow injection for low-contrast dose spectral pulmonary artery CT angiography

Purpose

The patient safety of iodine contrast-enhanced pulmonary artery CT angiography (CTPA) is widely concerned. This study aimed to investigate the image quality and immediate patient safety of spectral CTPA using a lower-contrast dose pre-dual-flow injection method.

Methods

This retrospective study included 120 patients with suspected pulmonary embolisms who received spectral CTPA between February and December 2022. Patients were divided into normal contrast injection (Group A, n=60) and pre-dual-flow group (Group B, n=60). CT values of pulmonary arteries (PAs) at different levels, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR), arteriovenous separation performance, and beam hardening artifact (BHA) index of two sets of images were measured or calculated. The subjective image quality and immediate patient safety were also scored using the three-point method.

Results

Group B had a contrast dose reduction by 42.5 % (60 vs. 34.5 mL). Radiation exposure dose was not statistically different between the two groups (P>0.05). CT values of different-level PAs on group B images were higher than those on group A images (P<0.05). Group B images had higher SNR and CNR, better arteriovenous separation between PA trunk and pulmonary vein, and lower BHA index on soft tissue and PA (all P<0.05). For subjective evaluation of image quality, group B had a better score in beam hardening artifact (P<0.05). For immediate patient safety, the score in comfortability was statistically higher in group B, with P<0.05.

Conclusions

Comparing with the normal injection method, pre-dual-flow spectral CTPA with a lower contrast dose injected results in better image quality and shows potential in patient-safety promotion.

Chronic thromboembolic disease among patients undergoing surgical pulmonary embolectomy for acute pulmonary embolism

BACKGROUND

This study aimed to assess the prevalence of chronic thromboembolic lesions in the pulmonary arteries among patients undergoing pulmonary embolectomy for acute pulmonary embolism and their impact on treatment outcomes.

METHODS

We conducted a retrospective, single-center analysis of consecutive patients undergoing emergency pulmonary embolectomy for acute pulmonary embolism between 2013 and August 2021. According to European Society of Cardiology guidelines, the diagnosis was based on clinical presentation, imaging studies and laboratory tests. Surgery was selected as the optimal treatment modality within the Pulmonary Embolism Response Team. Based on the intraoperatively identified chronic lesions patients were divided into two groups: acute only and acute/chronic. The analysis comprised history, laboratory and imaging studies, early and long-term mortality, and postoperative complications. We determined predictive factors for chronic thromboembolic lesions and risk factors for death.

RESULTS

The analysis included 33 patients. Intraoperatively, 42% (14) of patients had chronic lesions. Predictive factors for these lesions are the duration of symptoms >1 week (OR=13.75), pulmonary artery dilatation >3.15 cm (OR=39.00) and right ventricle systolic pressure >52 mmHg (OR=29.33). No hospital deaths occurred in the acute only group and two in the acute/chronic group (0% vs. 14.3%; P=0.172). Risk factors for death are the duration of symptoms >3 weeks (HR=7.35) and postoperative use of extracorporeal membrane oxygenation (HR=7.04).

CONCLUSIONS

Acute thromboembolic disease overlapping chronic clots is relatively common among patients undergoing pulmonary artery embolectomy. A detailed evaluation of the patient's medical history and imaging studies can identify these patients, as they require special attention when making treatment decisions. Surgical treatment in a center of expertise in pulmonary endarterectomy seems reasonable.

Machine learning assisted feature identification and prediction of hemodynamic endpoints using computed tomography in patients with CTEPH

Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare but potentially curable cause of pulmonary hypertension (PH). Currently PH is diagnosed by right heart catheterisation. Computed tomography (CT) is used for ruling out other causes and operative planning. This study aims to evaluate importance of different quantitative/qualitative imaging features and develop a supervised machine learning (ML) model to predict hemodynamic risk groups. 127 Patients with diagnosed CTEPH who received preoperative right heart catheterization and thoracic CTA examinations (39 ECG-gated; 88 non-ECG gated) were included. 19 qualitative/quantitative imaging features and 3 hemodynamic parameters [mean pulmonary artery pressure, right atrial pressure (RAP), pulmonary artery oxygen saturation (PA SaO2)] were gathered. Diameter-based CT features were measured in axial and adjusted multiplane reconstructions (MPR). Univariate analysis was performed for qualitative and quantitative features. A random forest algorithm was trained on imaging features to predict hemodynamic risk groups. Feature importance was calculated for all models. Qualitative and quantitative parameters showed no significant differences between ECG and non-ECG gated CTs. Depending on reconstruction plane, five quantitative features were significantly different, but mean absolute difference between parameters (MPR vs. axial) was 0.3 mm with no difference in correlation with hemodynamic parameters. Univariate analysis showed moderate to strong correlation for multiple imaging features with hemodynamic parameters. The model achieved an AUC score of 0.82 for the mPAP based risk stratification and 0.74 for the PA SaO2 risk stratification. Contrast agent retention in hepatic vein, mosaic attenuation pattern and the ratio right atrium/left ventricle were the most important features among other parameters. Quantitative and qualitative imaging features of reconstructions correlate with hemodynamic parameters in preoperative CTEPH patients-regardless of MPR adaption. Machine learning based analysis of preoperative imaging features can be used for non-invasive risk stratification. Qualitative features seem to be more important than previously anticipated.

Computed tomography-based radiomics model to predict adverse clinical outcomes in acute pulmonary embolism

This preliminary study investigated the feasibility of a combined model constructed using radiomic features based on computed tomography (CT) and clinical features to predict adverse clinical outcomes in acute pulmonary embolism (APE). Currently, there is no widely recognized predictive model. Patients with confirmed APE who underwent CT pulmonary angiography were retrospectively categorized into good and poor prognosis groups. Seventy-four patients were randomized into a training (n = 51) or validation (n = 23) cohort. Feature extraction was performed using 3D-Slicer software. The least absolute shrinkage and selection operator regression was used to identify the optimal radiomics features and calculate the radiomics scores; subsequently, the radiomics model was developed. A combined predictive model was constructed based on radiomics scores and selected clinical features. The predictive efficacy of the three models (radiomics, clinical and combined) was assessed by plotting receiver operating characteristic curves. Furthermore, the calibration curves were graphed and the decision curve analysis was performed. Four radiomic features were screened to calculate the radiomic score. Right ventricular to left ventricular ratio (RV/LV) ≥ 1.0 and radiomics score were independent risk factors for adverse clinical outcomes. In the training and validation cohorts, the areas under the curve (AUCs) for the RV/LV ≥ 1.0 (clinical) and radiomics score prediction models were 0.778 and 0.833 and 0.907 and 0.817, respectively. The AUCs for the combined model of RV/LV ≥ 1.0 and radiomics score were 0.925 and 0.917, respectively. The combined and radiomics models had high clinical assessment efficacy for predicting adverse clinical outcomes in APE, demonstrating the clinical utility of both models. Calibration curves exhibited a strong level of consistency between the predictive and observed probabilities of poor and good prognoses in the combined model. The combined model of RV/LV ≥ 1.0 and radiomics score based on CT could accurately and non-invasively predict adverse clinical outcomes in patients with APE.

Improved image quality in CT pulmonary angiography using deep learning-based image reconstruction

We investigated the effect of deep learning-based image reconstruction (DLIR) compared to iterative reconstruction on image quality in CT pulmonary angiography (CTPA) for suspected pulmonary embolism (PE). For 220 patients with suspected PE, CTPA studies were reconstructed using filtered back projection (FBP), adaptive statistical iterative reconstruction (ASiR-V 30%, 60% and 90%) and DLIR (low, medium and high strength). Contrast-to-noise ratio (CNR) served as the primary parameter of objective image quality. Subgroup analyses were performed for normal weight, overweight and obese individuals. For patients with confirmed PE (n = 40), we further measured PE-specific CNR. Subjective image quality was assessed independently by two experienced radiologists. CNR was lowest for FBP and enhanced with increasing levels of ASiR-V and, even more with increasing strength of DLIR. High strength DLIR resulted in an additional improvement in CNR by 29-67% compared to ASiR-V 90% (p < 0.05). PE-specific CNR increased by 75% compared to ASiR-V 90% (p < 0.05). Subjective image quality was significantly higher for medium and high strength DLIR compared to all other image reconstructions (p < 0.05). In CT pulmonary angiography, DLIR significantly outperforms iterative reconstruction for increasing objective and subjective image quality. This may allow for further reductions in radiation exposure in suspected PE.

Comprehensive imaging in patients with suspected pulmonary arterial hypertension

Currently, several imaging techniques are being used for a comprehensive evaluation of patients with suspected pulmonary hypertension (PH), in order to provide information that may clarify the presence and identify the aetiology of this complex pathology. The current paper is focused on recent updates regarding the importance of comprehensive imaging techniques for patients with suspected PH. Transthoracic echocardiography that can mainly detect right ventricle pressure overload and dysfunction is the cornerstone of imaging evaluation, while right heart catheterisation remains the gold standard assessment method. Chest radiography that may exclude pleuroparenchymal lung diseases, CT, the primary imaging modality for the assessment of lung parenchyma and CT pulmonary angiography, that allows for the non-invasive assessment of the pulmonary arteries, are equally important. Imaging techniques like dual-energy CT, single photon emission CT and ventilation perfusion scan may provide accurate diagnostic information for patients with chronic thromboembolic PH. Cardiac MRI provides the most accurate three-dimensional characterisation of the right ventricle. Accurate use of diagnostic imaging algorithms allows early detection of the disease, with the constant goal of improved PH patients prognosis.

Predictive Value of Pulmonary Artery Distensibility for Short-Term Adverse Clinical Outcomes in Patients with Acute Pulmonary Embolism

We aimed to explore the relationship between pulmonary artery distensibility obtained from computed tomography pulmonary angiography (CTPA) and short-term adverse clinical outcomes in patients with acute pulmonary embolism (APE). We included patients who underwent retrospective electrocardiogram-gated CTPA and were subsequently diagnosed with APE. Patients were categorized into good and poor outcome groups based on short-term clinical outcomes. Pulmonary artery distensibility (AD), right ventricle/left ventricle (RV/LV) ratio, and pulmonary artery obstruction index (PAOI) were measured, and the receiver operating characteristic curves were constructed. Sixty-four patients with APE (good outcome, 46; poor outcome, 18) were enrolled. AD, RV/LV ratio, and PAOI differed significantly between groups (P < 0.05). Pulmonary artery AD in the good outcome group was greater than that in the poor outcome group (P < 0.001). The poor outcome group exhibited a higher RV/LV ratio and PAOI than the good outcome group (P < 0.05). AD and PAOI were independent predictors of adverse clinical outcomes. Areas under the curve for AD and PAOI were 0.860 (95% confidence interval [CI]: 0.750-0.934) and 0.675 (95%CI: 0.546-0.786), and the combined curve of the AD and RV/LV ratio was 0.906 (95%CI: 0.806-0.965). The calibration curve showed a combined curve superior to the other curves. The decision curve showed high clinical application value of the combined curve. Retrospective electrocardiogram-gated CTPA-derived AD could serve as an indicator for predicting short-term adverse clinical outcomes in APE. Combining AD and PAOI has a high predictive value for short-term adverse clinical outcomes.

Risk factors and treatment interventions associated with incomplete thrombus resolution and pulmonary hypertension after pulmonary embolism

BACKGROUND

Residual pulmonary vascular occlusion (RPVO) affects one half of patients after a pulmonary embolism (PE). The relationship between the risk factors and therapeutic interventions for the development of RPVO and chronic thromboembolic pulmonary hypertension is unknown.

METHODS

This retrospective review included PE patients within a 26-month period who had baseline and follow-up imaging studies (ie, computed tomography [CT], ventilation/perfusion scans, transthoracic echocardiography) available. We collected the incidence of RPVO, percentage of pulmonary artery occlusion (%PAO), baseline CT %PAO, most recent CT %PAO, and difference between the baseline and most recent %PAO on CT (Δ%PAO).

RESULTS

A total of 354 patients had imaging reports available; 197 with CT and 315 with transthoracic echocardiography. The median follow-up time was 144 days (interquartile range [IQR], 102-186 days). RPVO was present in 38.9% of the 354 patients. The median Δ%PAO was -10.0% (IQR, -32% to -1.2%). Fewer patients with a provoked PE developed RPVO (P ≤ .01), and the initial troponin level was lower in patients who developed RPVO (P = .03). The initial thrombus was larger in the patients who received advanced intervention vs anticoagulation (baseline CT %PAO: median, 61.2%; [IQR, 27.5%-75.0%] vs median, 12.5% [IQR, 2.5%-40.0%]; P ≤ .0001). Catheter-directed thrombolysis (CDT; median Δ%PAO, -47.5%; IQR, -63.7% to -8.7%) and surgical pulmonary embolectomy (SPE; median Δ%PAO, -42.5; IQR, -68.1% to -18.7%) had the largest thrombus reduction compared with anticoagulation (P = .01). Of the 354 patients, 76 developed pulmonary hypertension; however, only 14 received pulmonary hypertension medications and 12 underwent pulmonary thromboendarterectomy. Cancer (odds ratio [OR], 1.7) and planned prolonged anticoagulation (>1 year; OR, 2.20) increased the risk of RPVO. In contrast, the risk was lower for men (OR, 0.61), patients with recent surgery (OR, 0.33), and patients treated with SPE (OR, 0.42). A larger Δ%PAO was found in men (coefficient, -8.94), patients with a lower body mass index (coefficient, -0.66), patients treated with CDT (coefficient, -18.12), and patients treated with SPE (coefficient, -21.69). A lower Δ%PAO was found in African-American patients (coefficient, 7.31).

CONCLUSIONS

The use of CDT and SPE showed long-term benefit in thrombus reduction.

A Retrospective Study on the Incidence of Pulmonary Embolism in Immobilized Spinal Cord Injury Patients

Introduction The development of pulmonary embolism (PE) remains the main cause of morbidity and mortality in patients with spinal cord injuries. Multiple factors have been identified to predict the presence of PE in spinal cord injury patients, however, local data is scarce. The objective of this study is to evaluate the incidence of PE among spinal cord injury patients and analysis of predictive risk factors. Material and methods This is a retrospective study among spinal cord injury patients admitted to a tertiary hospital in Malaysia between January 2018 and December 2019. All spinal cord injury patients with symptoms suggestive of venous thromboembolism (VTE) such as tachycardia and shortness of breath were included in this study. Demographic data such as age, gender, types of VTE prophylaxis (mechanical or chemical), and radiological findings of computerized tomography pulmonary angiogram (CTPA) were analyzed. Results A total of 373 patients were included in the study. 301 of them have undergone spinal surgery. There were 251 males (75.75%) and 124 females (33.24%). The mean age of the subjects was 48.63 ± 17.45 years. The mean length of hospital stay is 42.74 ± 41.51 days. 151 (40.48%) patients received DVT prophylaxis while 222 (59.52%) patients did not. The incidence of PE among spinal cord injury patients with VTE symptoms is 25 patients (6.70%). Of that, 15 patients received medical treatment only, seven received mechanical and pharmacological prophylaxis and three did not receive any prophylaxis. In the variable analyses, none of the variables (age and types of prophylaxis) could significantly predict the occurrence of VTE. Conclusion PE is a frequent complication in immobilized spinal cord injury patients despite receiving thromboprophylaxis treatment. No strong predictors for PE were identified in the present study. However, patients who received any type of thromboprophylaxis was found to be statistically significant when compared to patients who did not receive any thromboprophylaxis in term of the presence of PE.

COVID-19 vaccine-induced immune thrombotic thrombocytopenia: a review

Rare but serious thrombotic incidents in relation to thrombocytopenia, termed vaccine-induced immune thrombotic thrombocytopenia (VITT), have been observed since the vaccine rollout, particularly among replication-defective adenoviral vector-based severe acute respiratory syndrome coronavirus 2 vaccine recipients. Herein, we comprehensively reviewed and summarized reported studies of VITT following the coronavirus disease 2019 (COVID-19) vaccination to determine its prevalence, clinical characteristics, as well as its management. A literature search up to October 1, 2021 using PubMed and SCOPUS identified a combined total of 720 articles. Following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guideline, after screening the titles and abstracts based on the eligibility criteria, the remaining 47 full-text articles were assessed for eligibility and 29 studies were included. Findings revealed that VITT cases are strongly related to viral vector-based vaccines, which are the AstraZeneca COVID-19 vaccine (95%) and the Janssen COVID-19 vaccine (4%), with much rarer reports involving messenger RNA-based vaccines such as the Moderna COVID-19 vaccine (0.2%) and the Pfizer COVID-19 vaccine (0.2%). The most severe manifestation of VITT is cerebral venous sinus thrombosis with 317 cases (70.4%) and the earliest primary symptom in the majority of cases is headache. Intravenous immunoglobulin and non-heparin anticoagulant are the main therapeutic options for managing immune responses and thrombosis, respectively. As there is emerging knowledge on and refinement of the published guidelines regarding VITT, this review may assist the medical communities in early VITT recognition, understanding the clinical presentations, diagnostic criteria as well as its management, offering a window of opportunity to VITT patients. Further larger sample size trials could further elucidate the link and safety profile.

Role of pulmonary perfusion magnetic resonance imaging for the diagnosis of pulmonary hypertension: A review

Among five types of pulmonary hypertension, chronic thromboembolic pulmonary hypertension (CTEPH) is the only curable form, but prompt and accurate diagnosis can be challenging. Computed tomography and nuclear medicine-based techniques are standard imaging modalities to non-invasively diagnose CTEPH, however these are limited by radiation exposure, subjective qualitative bias, and lack of cardiac functional assessment. This review aims to assess the methodology, diagnostic accuracy of pulmonary perfusion imaging in the current literature and discuss its advantages, limitations and future research scope.

Catheter-directed mechanical thrombectomy in a patient with high-risk pulmonary embolism complicated by out-of-hospital cardiac arrest: a case report

Background

Pulmonary embolism (PE) is common, and it is the third leading cause of cardiovascular death. The management of patients with high-risk PE generally consists of systemic thrombolysis; however, surgical or catheter-directed treatment (CDT) can be considered in selected cases.

Case summary

A 78-year-old female patient presenting with acute severe dyspnoea develops out-of-hospital cardiac arrest (OHCA). She was admitted with return of spontaneous circulation and a critical haemodynamic state upon arrival to the catheterization laboratory with an estimated no-flow time of 1 min and low-flow time of 52 min. An acute pulmonary angiogram reveals massive PE. After a PE response team conference, the patient was not found eligible for extracorporeal membrane oxygenation, surgery, or thrombolysis. The patient was treated with catheter-directed mechanical thrombectomy 129 min after first medical contact. The patient recovered and was discharged without any neurological deficits.

Discussion

Catheter-directed mechanical thrombectomy was a successful treatment in a patient with OHCA secondary to high-risk PE, where thrombolysis and surgical interventions were considered contraindicated. This case underlines the future perspectives of CDT and also that a multidisciplinary team approach may benefit patients with high-risk PE.

Role of artificial intelligence in oncologic emergencies: a narrative review

Oncologic emergencies are a wide spectrum of oncologic conditions caused directly by malignancies or their treatment. Oncologic emergencies may be classified according to the underlying physiopathology in metabolic, hematologic, and structural conditions. In the latter, radiologists have a pivotal role, through an accurate diagnosis useful to provide optimal patient care. Structural conditions may involve the central nervous system, thorax, or abdomen, and emergency radiologists have to know the characteristics imaging findings of each one of them. The number of oncologic emergencies is growing due to the increased incidence of malignancies in the general population and also to the improved survival of these patients thanks to the advances in cancer treatment. Artificial intelligence (AI) could be a solution to assist emergency radiologists with this rapidly increasing workload. To our knowledge, AI applications in the setting of the oncologic emergency are mostly underexplored, probably due to the relatively low number of oncologic emergencies and the difficulty in training algorithms. However, cancer emergencies are defined by the cause and not by a specific pattern of radiological symptoms and signs. Therefore, it can be expected that AI algorithms developed for the detection of these emergencies in the non-oncological field can be transferred to the clinical setting of oncologic emergency. In this review, a craniocaudal approach was followed and central nervous system, thoracic, and abdominal oncologic emergencies have been addressed regarding the AI applications reported in literature. Among the central nervous system emergencies, AI applications have been reported for brain herniation and spinal cord compression. In the thoracic district the addressed emergencies were pulmonary embolism, cardiac tamponade and pneumothorax. Pneumothorax was the most frequently described application for AI, to improve sensibility and to reduce the time-to-diagnosis. Finally, regarding abdominal emergencies, AI applications for abdominal hemorrhage, intestinal obstruction, intestinal perforation, and intestinal intussusception have been described.

A machine learning model identifies patients in need of autoimmune disease testing using electronic health records

Systemic autoimmune rheumatic diseases (SARDs) can lead to irreversible damage if left untreated, yet these patients often endure long diagnostic journeys before being diagnosed and treated. Machine learning may help overcome the challenges of diagnosing SARDs and inform clinical decision-making. Here, we developed and tested a machine learning model to identify patients who should receive rheumatological evaluation for SARDs using longitudinal electronic health records of 161,584 individuals from two institutions. The model demonstrated high performance for predicting cases of autoantibody-tested individuals in a validation set, an external test set, and an independent cohort with a broader case definition. This approach identified more individuals for autoantibody testing compared with current clinical standards and a greater proportion of autoantibody carriers among those tested. Diagnoses of SARDs and other autoimmune conditions increased with higher model probabilities. The model detected a need for autoantibody testing and rheumatology encounters up to five years before the test date and assessment date, respectively. Altogether, these findings illustrate that the clinical manifestations of a diverse array of autoimmune conditions are detectable in electronic health records using machine learning, which may help systematize and accelerate autoimmune testing.

The many roles of urgent catheter interventions: from myocardial infarction to acute stroke and pulmonary embolism

INTRODUCTION

Cardiovascular diseases (CVDs) are the leading cause of cardiovascular mortality and a major contributor to disability worldwide. The prevalence of CVDs is continuously increasing, and from 1990 to 2019, it has doubled. Global cardiovascular mortality has increased from 12.1 million in 1990 to 18.6 million cases in 2019. The development of therapeutic options for these diseases is at the forefront of interest concerning the extensive socio-economic consequences. Modern endovascular transcatheter therapeutic options contribute to the reduction of cardiovascular morbidity and mortality.

AREAS COVERED

The article concentrates on the triad of the most common causes of acute cardiovascular mortality and morbidity - myocardial infarction, ischemic stroke, and pulmonary embolism. Current evidence-based indications, specific interventional techniques, and remaining unsolved issues are reviewed and compared. A personal perspective on the possible implications for the future is provided.

EXPERT OPINION

Primary angioplasty for ST-segment elevation myocardial infarction is a well-established therapeutic option with proven mortality benefits. We suppose that catheter-based interventions for acute stroke will spread quickly from centers of excellence to routine clinical practice. We believe that ongoing research will provide a basis for the expansion of interventional treatment of pulmonary embolism soon.

Perioperative Management of Incidental Pulmonary Embolisms on Trauma CT Scans: A Narrative Review

Unsuspected pulmonary embolism (PE) may be identified on an initial trauma computed tomography (CT) scan. The clinical importance of these incidental PEs remains to be elucidated. In patients who require surgery, careful management is needed. We sought to investigate the optimal perioperative management of such patients, including the use of pharmacological and mechanical thromboprophylaxis, possible thrombolytic therapy, and inferior vena cava (IVC) filters. A literature search was conducted, and all relevant articles were identified, investigated, and included. Medical guidelines were also consulted where appropriate. Pharmacological thromboprophylaxis is the mainstay of preoperative treatment, and low-molecular-weight heparins, fondaparinux, and unfractionated heparin may all be used. It has been suggested that prophylaxis should be administered as soon as possible after trauma. Such agents may be contraindicated in patients with significant bleeding, and mechanical prophylaxis and inferior vena cava filters may be favoured in these patients. Therapeutic anticoagulation and thrombolytic therapies may be considered but are associated with an increased risk of haemorrhage. Delaying surgery might help to minimise the risk of recurrent venous thromboembolism, and any interruption of prophylaxis must be strategically planned. Recommendations for postoperative care include a continuation of prophylaxis and therapeutic anticoagulation, with follow-up clinical evaluation within six months. Incidental PE is a common finding on trauma CT scans. Although the clinical significance is unknown, careful management of the balance between anticoagulation and bleeding is needed, especially in trauma patients and even more so in trauma patients requiring surgery.

Evolutionary changes in thrombus features on computed tomography: An effective approach for identifying subacute pulmonary embolism

OBJECTIVE

Thrombus features on computed tomography (CT) play a key role in distinguishing between acute and chronic pulmonary embolisms (PEs). However, the thrombus features of subacute PE are largely unknown.

METHODS

This retrospective study included 358 patients (age, 65 ± 16 years; percentage of men, 38%) diagnosed with PE from 2008 to 2019. The patients were divided into a study group and a verification group. Thrombus features that changed over time were determined in the study group according to the time of PE occurrence. Next, we determined the thrombus features of subacute PE and verified them in the verification group. Finally, we compared clinical deterioration and the 1-month mortality rate between the patients with acute and subacute PEs.

RESULTS

The main feature of eccentric thrombi that changed over time was the angle with the arterial wall, whereas those of centric thrombi were recanalization and heterogeneity. Taken together, the features of subacute PE were determined to be an obtuse angle with the arterial wall, recanalization, and heterogeneity. The accuracy of these features in identifying subacute PE was 94% during verification. Between the patients with acute and subacute PEs, there was no significant difference in clinical deterioration (19% vs 14%; P = .32) or the 1-month mortality rate (15% vs 8%; P = .11). With multivariate analysis, subacute events were also not associated with clinical deterioration (P = .8) or the 1-month mortality rate (P = .11).

CONCLUSIONS

We determined the time trend of thrombus features on CT in patients with PE and found that these features can improve the identification of subacute events. Patients with acute and subacute PEs do not have different risks of clinical deterioration and 1-month mortality.

A Case of Chronic Pulmonary Embolism Resulting in Pulmonary Hypertension and Decompensated Right Heart Failure

Chronic thromboembolic pulmonary hypertension is a deadly condition that results from thrombus organization and formation of fibrous tissue in the large and/or middle-sized pulmonary artery; as a result, pulmonary vascular resistance increases resulting in pulmonary hypertension and right heart failure. Untreated chronic pulmonary embolism causes decompensated right heart failure. Early diagnosis and appropriate treatment are crucial for improving survival. Pulmonary endarterectomy (PEA) is the treatment of choice as it reduces pulmonary vascular resistance. For patients who are not a candidate for PEA, alternative treatment options improve quality of life.

Clinical outcomes and echocardiographic characteristics between African American and Caucasian patients with acute pulmonary embolism

Background

Despite socioeconomic disparities, no association between clinical presentation and poor outcomes explains a higher mortality in African Americans with pulmonary embolism (PE). The objective is to identify the co-morbidities and echocardiographic characteristics associated with increased mortality in African American patients.

Methods

This is a cross-sectional study of Caucasian or African American patients with PE diagnosed between October 2015 and December 2017 at University of Maryland Medical Center. The outcomes were in-hospital death, length of stay, and bleeding.

Results

There were 303 African Americans and 343 Caucasians. Caucasians were older ( p = 0.007), males ( p = 0.01) with history of coronary artery revascularization (CABG ( p = 0.001), coronary stents ( p = 0.001)), trauma ( p = 0.007), and/or recent surgeries ( p = 0.0001). African Americans exhibited higher rates of diabetes ( p = 0.01), chronic kidney disease ( p = 0.0005), and smoking ( p = 0.04). Severity of PE was similar between groups and there was no difference in clot burden size. African Americans had more right ventricular strain on Computer Tomography ( p = 0.001) and echocardiogram ( p = 0.004); also, underfilled left ventricles ( p = 0.02) and higher right ventricular systolic pressures ( p = 0.001). There was no difference in hospital mortality (7.1% vs. 7.9%, p = 0.71), length of stay (13.1 ± 16.7 vs 12.8 ± 14.9, p = 0.80) and bleeding (9.0% vs.8.3%. p = 0.72). Mortality was higher in African Americans who received advanced therapies (3.8% vs. 18.8%, p = 0.02). The risk of death increased with age (OR 1.04; 95%CI 1.020–1.073) and with advanced therapies (OR 2.43; 95%CI 1.029–5.769).

Conclusions

Differences in co-morbidities, radiologic findings, and echocardiographic characteristics that may contribute to higher mortality in African American patients, specifically those receiving advanced therapies.

Diagnosis, Diagnostic Tools, and Risk Stratification for Contemporary Treatment of Pulmonary Embolism

Pulmonary embolism (PE) is quite common and is associated with significant morbidity and mortality. It is estimated that it is the cause of approximately 100,000 annual deaths in the United States. With great variability in presenting symptoms of PE, poor recognition of PE can be fatal. As such, many risk scores have been created to identify the sickest patients. Choosing the appropriate imaging modality is also critical. Invasive pulmonary angiography was once the gold standard to establish the diagnosis. With the advent of nuclear imaging, V/Q scans, invasive angiography has been phased out for diagnosing acute PE. At present, the standard for diagnosis of acute PE is computed tomography pulmonary angiography. In select patient cohorts, nuclear studies remain the modality of choice. Once the diagnosis of acute PE is established, there is a broad spectrum of severity in outcome which has led to substantial focus and development of risk stratification prediction models. We will discuss making the proper diagnosis with contemporary diagnostic tools and risk stratifying patients with PE to receive the correct treatment.

Saddle versus non-saddle pulmonary embolism: differences in the clinical, echocardiographic, and outcome characteristics

The central location, the size, and instability of saddle pulmonary embolism (PE) have raised considerable concerns regarding its hemodynamic consequences and the optimal management approach. Sparse and conflicting reports have addressed these concerns in the past. We aimed to evaluate the clinical presentation, hemodynamic and echocardiographic effects, as well as the outcomes of saddle PE, and compare the results with those of non-saddle type. This was a retrospective study of 432 adult patients with saddle and non-saddle PE. Overall, 432 patients were diagnosed with PE by computed tomography pulmonary angiography (CTPA). Seventy-three (16.9%) had saddle PE, and 359 had non-saddle PE. Compared to those with non-saddle PE, patients with saddle PE presented more frequently with tachycardia (68.5% vs. 46.2%, P= .001), and tachypnea (58.9% vs. 42.1%, P= .009) on admission, required more frequent intensive care unit (ICU) admissions (45.8% vs. 26.6%, P= .001) and thrombolysis/thrombectomy use (19.1% vs. 6.7%, P= .001), and were at more risk of developing decompensation and cardiac arrest after their initial admission (15.3% vs. 5.9%, P= .006). On echocardiography, right ventricular (RV) enlargement (60% vs. 31.1%, P= .000), RV dysfunction (45.8% vs. 22%, P= .000), and RV systolic pressure (RVSP) of greater than 40 mmHg (61.5% vs. 39.2%, P= .003) were significantly more observed with saddle PE. The two groups did not differ concerning the rates of hypotension (17.8% vs. 18.7%, P= .864) and hypoxemia (41.1% vs. 34.3%, P= .336) on admission and mortality rates. A logistic regression model indicated that the use of oral contraceptive pills (OCP), RVSP > 40 mmHg, and development of hypotension and decompensation following admission were associated with an increased likelihood of having saddle embolus. Saddle PE accounts for a higher proportion among all PE cases than previously reported. Patients with saddle PE tend to present more frequently with adverse hemodynamic and echocardiographic changes and decompensate after their initial presentation. OCP use, development of hypotension, and decompensation following admission and RVSP > 40 mmHg are significant predictors of saddle PE. These characteristics should not be overlooked when managing patients with saddle PE.

Prevalence, Outcome, and Optimal Management of Free-Floating Right Heart Thrombi in the Context of Pulmonary Embolism, a Systematic Review and Meta-Analysis

Free-floating right-heart thrombus (FFRHT) in the context of a pulmonary embolism (PE) is a rare but serious encounter with no guidelines addressing its management. We performed a systematic review and meta-analysis addressing prevalence, clinical behavior, and outcomes of FFRHT associated with PE. Among the included 397 patients with FFRHT and PE, dyspnea was the main presenting symptom (73.3%). Obstructive shock was documented in 48.9% of cases. Treatment with thrombolytic therapy, surgical thrombectomy, and percutaneous thrombectomy was documented in 43.8%, 32.7%, and 6.5% of patients, respectively. The overall mortality rate was 20.4%. Syncope ( p: 0.027), chest pain ( p: 0.006), and obstructive shock ( p: 0.037) were significantly associated with mortality. Use of thrombolytic therapy was significantly associated with survival ( p: 0.008). A multivariate logistic regression model to determine mortality predictors revealed that syncope (OR: 1.97, 95% CI: 1.06–3.65, p: 0.03), and obstructive shock (OR: 2.23, 95% CI: 1.20–4.14, p: 0.01) were associated with increased death odds. Treatment with thrombolytic therapy (OR: 0.22, 95% CI: 0.086–0.57, p: 0.002) or surgical thrombectomy (OR: 0.35, 95% CI: 0.137–0.9, p: 0.03) were associated with reduced death odds. Meta-analysis of observational studies revealed a pooled prevalence of FFRHT among all PE cases of 8.1%, and overall mortality of 23%. Although uncommon, the presence of FFRHT in the context of PE is associated with high obstructive shock and mortality rates. Favorable survival odds are observed with thrombolytic therapy and surgical thrombectomy. Data are derived from case reports and observational studies. Clinical trials elucidating these findings are needed.

Pediatric Pulmonary Embolism: Imaging Guidelines and Recommendations

In contrast with the algorithms and screening criteria available for adults with suspected pulmonary embolism, there is a paucity of guidance on the diagnostic approach for children. The incidence of pulmonary embolism in the pediatric population and young adults is higher than thought, and there is an urgent need for updated guidelines for the imaging approach to diagnosis in the pediatric population. This article presents an up-to-date review of imaging techniques, characteristic radiologic findings, and an evidence-based algorithm for the detection of pediatric pulmonary embolism to improve the care of pediatric patients with suspected pulmonary embolism.

Identification of chronic thromboembolic pulmonary hypertension on CTPAs performed for diagnosing acute pulmonary embolism depending on level of expertise

BACKGROUND

Expert reading often reveals radiological signs of chronic thromboembolic pulmonary hypertension (CTEPH) or chronic PE on computed tomography pulmonary angiography (CTPA) performed at the time of acute pulmonary embolism (PE) presentation preceding CTEPH. Little is known about the accuracy and reproducibility of CTPA reading by radiologists in training in this setting.

OBJECTIVES

To evaluate 1) whether signs of CTEPH or chronic PE are routinely reported on CTPA for suspected PE; and 2) whether CTEPH-non-expert readers achieve comparable predictive accuracy to CTEPH-expert radiologists after dedicated instruction.

METHODS

Original reports of CTPAs demonstrating acute PE in 50 patients whom ultimately developed CTEPH, and those of 50 PE who did not, were screened for documented signs of CTEPH. All scans were re-assessed by three CTEPH-expert readers and two CTEPH-non-expert readers (blinded and independently) for predefined signs and overall presence of CTEPH.

RESULTS

Signs of chronic PE were mentioned in the original reports of 14/50 cases (28%), while CTEPH-expert radiologists had recognized 44/50 (88%). Using a standardized definition (≥3 predefined radiological signs), moderate-to-good agreement was reached between CTEPH-non-expert readers and the experts' consensus (k-statistics 0.46; 0.61) at slightly lower sensitivities. The CTEPH-non-expert readers had moderate agreement on the presence of CTEPH (κ-statistic 0.38), but both correctly identified most cases (80% and 88%, respectively).

CONCLUSIONS

Concomitant signs of CTEPH were poorly documented in daily practice, while most CTEPH patients were identified by CTEPH-non-expert readers after dedicated instruction. These findings underline the feasibility of achieving earlier CTEPH diagnosis by assessing CTPAs more attentively.

Diagnostic yield of CT pulmonary angiography for pulmonary embolism in clinically suspected patients

Pulmonary embolism (PE) is a common medical problem. Its diagnostic criteria must be reviewed to determine the need for confirmatory testing. Computed tomography pulmonary angiography (CTPA) is the current standard of care, which provides accurate diagnosis with rapid turnaround. This study aimed to estimate the diagnostic yield of CTPA in clinically suspected PE patients in a tertiary care hospital in Saudi Arabia.Radiology records of all patients with clinically suspected PE who underwent CTPA between January 1, 2012 and September 30, 2018 were reviewed retrospectively. A radiologist with 10 years of professional experience interpreted and reported all cases. The Wells score with 2 tiers (likely and unlikely) was used to raise the clinical suspicion of PE.Positive results for PE were reported in 177 out of 534 clinically suspected cases (33%). Among the positive PE cases, 143 were acute (81%) and 34 (19%) were chronic. Bilateral, right-sided, and left-sided PE were found in 115 (65%), 37 (21%), and 25 (14%) cases, respectively. Involvement of the segmental branches, subsegmental branches, and the pulmonary trunk were noted in 152 (86%), 70 (40%), and 9 cases (5%), respectively. Saddle PE was found in (4%) of the cases. The lower lobe branches (right 55%, left 53%) and the upper lobe branches (right 47%, left 41%) were the most common sites of involvement.CTPA had a higher positive detection rate for PE among clinically suspected cases than its published diagnostic yield. Adequate clinical evaluation when selecting patients for CTPA is emphasized to minimize unjustified exposure of the patients to radiation and intravenous contrast administration. It is crucial for radiologists to provide detailed reports commenting on all relevant findings, including pertinent negatives. A template for reporting radiological findings for CTPA can be recommended for this purpose.

YEARS Algorithm Versus Wells' Score: Predictive Accuracies in Pulmonary Embolism Based on the Gold Standard CT Pulmonary Angiography

OBJECTIVES

This study retrospectively applied Wells' score and YEARS algorithm to the same sample of patients to evaluate the predictive performance of each when compared with the gold standard CT pulmonary angiography.

DESIGN

Retrospective analytical study.

SETTING

A tertiary University Hospital in Ireland.

PATIENTS

Data from 794 patients who underwent CT pulmonary angiography to rule out pulmonary embolism.

INTERVENTIONS

Patients were analyzed using retrospective application of both Wells' score and YEARS algorithm. Sensitivity, specificity, and diagnostic odds ratio were calculated and compared.

MEASUREMENTS AND MAIN RESULTS

Of 794 scans, 78 (9.8%) were positive for pulmonary embolism. The YEARS algorithm was more sensitive than the Wells' score (97.44% vs 74.36%) but was less specific (13.97% vs 33.94%). Furthermore, the diagnostic odds ratio of YEARS was higher than Wells' score (6.27 vs 1.48). YEARS provides better negative predictive value (98% vs 92.4%), and both scores have poor positive predictive value (10.9%).

CONCLUSIONS

Both scores successfully exclude pulmonary embolism, although YEARS has a better negative predictive value. Both exhibit poor positive predictive value.

Time series analysis of the in-hospital diagnostic process in suspected pulmonary embolism evaluated by computed tomography: An explorative study

PURPOSE

This retrospective study aims to analyze the distribution of demand and the duration of the diagnostic workup of suspected pulmonary embolism (PE) using computed tomography pulmonary angiography (CTPA).

METHODS

Time data from physical examination to report creation were identified for each CTPA in 2013 and 2018 at a tertiary hospital. Multivariable multinomial logistic and linear regression models were used to evaluate differences between 3 time intervals (I1: 6am-2pm, I2: 2pm-10pm, I3: 10pm-6am). A cosinor model was applied to analyze the amount of CTPA per hour.

RESULTS

The relative demand for CTPA from the emergency room was lower in l1 compared to l2 and l3 (I1/I2: odds ratio (OR) 0.84, 95 % confidence interval (CI) 0.78-0.91; I1/I3: OR 0.80, 95 % CI 0.72-0.89; peak 4:23 pm). Requests for in-patients displayed a tendency towards I1 (I1/2: OR 1.15, 95 % CI 1.06-1.24; l1/l3: OR 1.19, 95 % CI 1.07-1.33; peak 1:54 pm). The time from CTPA request to study was shorter in I3 compared to I1 and I2 in 2013 (I1/I3: ratio 5.23, 95 % CI 3.38-8.10; I2/I3: ratio 3.50, 95 % CI 2.24-5.45) and 2018 (I1/I3: ratio 2.27, 95 % CI 1.60-3.22; I2/I3: ratio 2.11, 95 % CI 1.50-2.97). This applied similarly to fatal cases (I1/I3: ratio 2.91, 95 % CI 1.78-4.75; I2/I3: ratio 2.45, 95 % CI1.52-3.95).

CONCLUSIONS

The temporal distribution of demand for CTPA depends on the sector of patient care and the processing time differs substantially during the day. Time series analysis can reveal such coherences and may help to optimize workflows in radiology departments.

Clinical importance of the distribution of pulmonary artery embolism in acute pulmonary embolism

Objective

To explore the clinical importance of the distribution of pulmonary artery embolism in acute pulmonary embolism (APE).

Methods

Sixty-four patients with APE were classified into mixed-type and distal-type pulmonary embolism groups. Their right ventricular systolic pressure (RVSP) and disease duration were recorded, and the diameter of their right ventricles was measured by ultrasound. The computed tomography angiographic clot load was determined as a Mastora score.

Results

Patients with distal-type pulmonary embolisms had significantly lower RVSPs (44.92 ± 17.04 vs 55.69 ± 17.66 mmHg), and significantly smaller right ventricular diameters (21.08 ± 3.06 vs 23.37 ± 3.48 mm) than those with mixed-type pulmonary embolisms. Additionally, disease duration was significantly longer in patients with distal-type pulmonary embolisms (14.33 ± 11.57 vs 8.10 ± 7.10 days), and they had significantly lower Mastora scores (20.91% ± 18.92% vs 43.96% ± 18.30%) than patients with mixed-type pulmonary embolisms. After treatment, RVSPs decreased significantly in patients with both distal-type and mixed-type pulmonary embolisms. Right ventricle diameters also decreased significantly in patients with mixed-type pulmonary embolisms after treatment.

Conclusion

Patients with mixed-type pulmonary embolisms are significantly more susceptible to pulmonary hypertension, enlarged right ventricular diameters, and shorter durations of disease than those with distal-type pulmonary embolisms. The distribution of pulmonary artery embolism in APE can provide a clinical reference.

Optimizing the diagnosis and assessment of chronic thromboembolic pulmonary hypertension with advancing imaging modalities

Imaging is key to nearly all aspects of chronic thromboembolic pulmonary hypertension including management for screening, assessing eligibility for pulmonary endarterectomy, and post-operative follow-up. While ventilation/perfusion scintigraphy, the gold standard technique for chronic thromboembolic pulmonary hypertension screening, can have excellent sensitivity, it can be confounded by other etiologies of pulmonary malperfusion, and does not provide structural information to guide operability assessment. Conventional computed tomography pulmonary angiography has high specificity, though findings of chronic thromboembolic pulmonary hypertension can be visually subtle and unrecognized. In addition, computed tomography pulmonary angiography can provide morphologic information to aid in pre-operative workup and assessment of other structural abnormalities. Advances in computed tomography imaging techniques, including dual-energy computed tomography and spectral-detector computed tomography, allow for improved sensitivity and specificity in detecting chronic thromboembolic pulmonary hypertension, comparable to that of ventilation/perfusion scans. Furthermore, these advanced computed tomography techniques, compared with conventional computed tomography, provide additional physiologic data from perfused blood volume maps and improved resolution to better visualize distal chronic thromboembolic pulmonary hypertension, an important consideration for balloon pulmonary angioplasty for inoperable patients. Electrocardiogram-synchronized techniques in electrocardiogram-gated computed tomography can also show further information regarding right ventricular function and structure. While the standard of care in the workup of chronic thromboembolic pulmonary hypertension includes a ventilation/perfusion scan, computed tomography pulmonary angiography, direct catheter angiography, echocardiogram, and coronary angiogram, in the future an electrocardiogram-gated dual-energy computed tomography angiography scan may enable a "one-stop" imaging study to guide diagnosis, operability assessment, and treatment decisions with less radiation exposure and cost than traditional chronic thromboembolic pulmonary hypertension imaging modalities.

Pulmonary embolism secondary to deep venous thrombosis: A retrospective and observational study for clinical characteristics and risk stratification

OBJECTIVE

To investigate the risk factors, predilection sites in pulmonary embolism (PE) patients caused by deep venous thrombosis (DVT) and explore the value of scoring systems in assessing the risk of PE in DVT patients.

METHODS

A total of 692 DVT patients were enrolled, and divided into no pulmonary embolism (NPE, 226, 32.66%), silent pulmonary embolism (SPE, 330, 47.67%) and featuring pulmonary embolism (FPE, 136, 19.65%) groups. For each group, the differences of clinical data and PE locations were compared, and the risk factors of PE secondary to DVT were analyzed. The predictive value of the scoring system for the diagnosis of PE and FPE was evaluated.

RESULTS

PE presented more in the bilateral pulmonary arteries (PAs) (249, 53.43%) and has no significant difference in PESI scores in different locations. Gender, DVT locations, and previous surgery were the independent risk factors of PE. DVT locations, previous history of COPD, and previous surgical interventions were the independent risk factors of FPE. The results for areas under the ROC curves were: AUC_(Wells) = 0.675, AUC _{(Revised Geneva)} = 0.601, AUC_(D-dimer) = 0.595 in the PE group; AUC_(Wells) = 0.722, AUC _{(Revised Geneva)} = 0.643, AUC_(D-dimer) = 0.557 in the FPE group.

CONCLUSIONS

PE secondary to DVT mostly occurs in the bilateral PAs. Male gender, DVT locations, and previous surgery increased the risk of PE. The Wells scoring system was more advantageous for evaluating the diagnosis of PE in patients with DVT.

Intelligent Platelet Morphometry

Technological advances in image-based platelet analysis or platelet morphometry are critical for a better understanding of the structure and function of platelets in biological research as well as for the development of better clinical strategies in medical practice. Recently, the advent of high-throughput optical imaging and deep learning has boosted platelet morphometry to the next level by providing a new set of capabilities beyond what is achievable with traditional platelet morphometry, shedding light on the unexplored domain of platelet analysis. This Opinion article introduces emerging opportunities in 'intelligent' platelet morphometry, which are expected to pave the way for a new class of diagnostics, pharmacometrics, and therapeutics.

High-risk pulmonary embolism with out-of-hospital cardiac arrest: Acute multidisciplinary approach leading to surgical embolectomy with good clinical outcome

Percutaneous pulmonary angiography may be used for early diagnosis of pulmonary embolism in the hemodynamic unstable patient. Pulmonary embolectomy is an effective treatment option in patients with acute high-risk pulmonary embolism.

Pulmonary Embolism Versus Mimics on Dual-energy Spectral Computed Tomography: An Algorithmic Approach

Pulmonary embolism is a commonly encountered diagnosis that is traditionally identified on conventional computed tomography angiography. Dual-energy computed tomography (DECT) is a new technology that may aid the initial identification and differential diagnosis of pulmonary embolism. In this review, we present an algorithmic approach for assessing pulmonary embolism on DECT, including acute versus chronic pulmonary embolism, relationship to conventional computed tomography angiography, surrogate for likelihood of hemodynamic significance, and alternative diagnoses for DECT perfusion defects.

Diagnostic yield of computed tomographic pulmonary angiography for suspected pulmonary embolism varies across settings within a community-based health system

PURPOSE

The diagnostic yield of computed tomographic pulmonary angiography (CTPA) for pulmonary embolism varies in the literature, and very little data is available regarding community-based systems. This study evaluates the yield of CTPA for pulmonary embolism across a variety of patient care settings in a community-based healthcare system, providing relevant benchmarks for potential quality improvement efforts.

METHODS

This retrospective study included data collected from three sites within a single community-based healthcare system, including a tertiary care level 1 trauma center, an urban community hospital, and a suburban free-standing emergency department. CTPAs were identified by Current Procedural Terminology codes, and diagnoses of pulmonary embolism were identified via International Classification of Diseases codes. A total of 7850 CTPA studies met criteria for inclusion between January 1, 2012, and October 8, 2014.

RESULTS

Pulmonary embolism was found in 884 (11.3%) of the studies performed. Outpatients had a lower yield of pulmonary embolism (3.8%, p < 0.001) compared with inpatients (14.1%) and emergency department patients (10.7%, p < 0.001). Patients with diagnoses of deep vein thrombosis or neoplasm had increased incidence of pulmonary embolism when compared with patients without these diagnoses (p < 0.001 for both).

CONCLUSION

The overall yield of CTPA for pulmonary embolism in this community-based system was similar to that at academic centers. The yield was significantly lower in the outpatient setting compared with studies originating in the emergency department or inpatient setting.

Efficacy of Computed Tomography Pulmonary Angiography as Non-invasive Imaging Biomarker for Risk Stratification of Acute Pulmonary Embolism

Objectives:

Massive and sub-massive pulmonary embolisms (PEs) are associated with high mortality and morbidity. The mainstay of treatment for PE is anticoagulation. However, high- and intermediate-risk patients may benefit from interventional thrombolytic therapy. Computed tomography pulmonary angiography (CTPA) is widely available, fast, and non-invasive technique, and it can identify pulmonary thrombus down to at least a segmental level. In this study, we attempt to evaluate the efficacy of CTPA as a non-invasive imaging biomarker for risk stratification of acute PE (APE) patients.

Material and Methods:

This is a prospective study conducted on 150 patients who proved to have APE by CTPA. The simplified PE severity index score was obtained. The pulmonary artery obstruction index (PAOI) using and right to left ventricular (RV/LV) diameter ratios were calculated.

Results:

The patients were divided into (1) high risk (shocked) and (2) non-high risk groups. There was a significant difference between the 1^st and 2^nd groups regarding PAOI. Hemodynamically stable patients were further subclassified according to the right ventricular dysfunction (RVD) into Group Ia (intermediate risk) and Group Ib (low risk). There was a significant difference between subgroups regarding PAOI (P < 0.0001, r = 0.385). Receiver operating characteristic curve analysis revealed PAOI >47% associated with RV/LV ratio >1.

Conclusion:

Our results support the use of CTPA as a surrogate imaging biomarker for both diagnosis and risk stratification of APE patients. CTPA allows assessment of clot burden through PAOI calculation and identification of intermediate-risk PE through the assessment of RVD.

Deep Learning Versus Iterative Reconstruction for CT Pulmonary Angiography in the Emergency Setting: Improved Image Quality and Reduced Radiation Dose

To compare image quality and the radiation dose of computed tomography pulmonary angiography (CTPA) subjected to the first deep learning-based image reconstruction (DLR) (50%) algorithm, with images subjected to the hybrid-iterative reconstruction (IR) technique (50%). One hundred forty patients who underwent CTPA for suspected pulmonary embolism (PE) between 2018 and 2019 were retrospectively reviewed. Image quality was assessed quantitatively (image noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR)) and qualitatively (on a 5-point scale). Radiation dose parameters (CT dose index, CTDI_vol; and dose-length product, DLP) were also recorded. Ninety-three patients were finally analyzed, 48 with hybrid-IR and 45 with DLR images. The image noise was significantly lower and the SNR (24.4 ± 5.9 vs. 20.7 ± 6.1) and CNR (21.8 ± 5.8 vs. 18.6 ± 6.0) were significantly higher on DLR than hybrid-IR images (p < 0.01). DLR images received a significantly higher score than hybrid-IR images for image quality, with both soft (4.4 ± 0.7 vs. 3.8 ± 0.8) and lung (4.1 ± 0.7 vs. 3.6 ± 0.9) filters (p < 0.01). No difference in diagnostic confidence level for PE between both techniques was found. CTDI_vol (4.8 ± 1.4 vs. 4.0 ± 1.2 mGy) and DLP (157.9 ± 44.9 vs. 130.8 ± 41.2 mGy∙cm) were lower on DLR than hybrid-IR images. DLR both significantly improved the image quality and reduced the radiation dose of CTPA examinations as compared to the hybrid-IR technique.

Weight-Adjusted Contrast Administration in the Computed Tomography Evaluation of Pulmonary Embolism

INTRODUCTION

Computed tomography pulmonary angiogram (CTPA) is widely considered the gold standard for diagnosis of pulmonary embolism (PE) with previous studies demonstrating high sensitivity and specificity. Despite this, nondiagnostic and indeterminate CTPA rates of 5%-26% remain a concern. As part of a continuing quality assurance program, a new weight-adjusted contrast dose and increased administration rate CTPA protocol was studied with an aim to improve diagnostic accuracy of PE evaluation.

METHODS

A total of 2,398 CTPA examinations were reviewed to assess pulmonary arterial enhancement and PE yield in this retrospective study. Between 1 August 2014 and 1 August 2015, 1,133 patients received a fixed-volume (60 mL) contrast dose technique at 4 mL/s (protocol A). A new protocol was then implemented as part of a continuing quality assurance program. Between 15 September 2015 and 15 September 2016, 1,265 patients received a weight-adjusted contrast dose (1 mL/kg) and increased administration rate (5 mL/s) CTPA technique (protocol B). Studies were classed into categories based on quality of study; diagnostic: HU > 211, nondiagnostic: HU < 211 and PE yield; positive, negative, and indeterminate. These variables were compared with cross-sectional surface area to assess the relationship between patient habitus, CTPA diagnostic quality, and PE yield.

RESULTS

A weight-adjusted contrast dose and increased administration rate CTPA protocol (protocol B) resulted in a significant increase in mean PA enhancement (P < .0001), 55.23% decrease in nondiagnostic studies and 43.04% decrease in indeterminate studies. Protocol B demonstrated increased positive and negative CTPA rates with decreased indeterminate rates from 12.38% to 7.04%. Comparison with cross-sectional area demonstrated significant increase in proportion of diagnostic studies and reduction in nondiagnostic and indeterminate CTPAs using protocol B in obese patients.

CONCLUSIONS

A weight-adjusted contrast dose and increased administration rate CTPA protocol can significantly increase PA enhancement, especially in obese patients, resulting in greater high-quality and fewer nondiagnostic and indeterminate CTPA examinations. A CTPA protocol with a higher rate of conclusive examinations can provide greater confidence in PE evaluation for reporting radiologists and accurate clinical decision-making pathways for referring physicians.

Pulmonary thromboembolism with computed tomography defined chronic thrombus is associated with higher mortality

With the advancement of computed tomography pulmonary angiography, differentiating between acute and chronic thrombus in pulmonary embolism has become more feasible. However, whether pulmonary embolism with chronic thrombus contributes to a higher mortality than pulmonary embolism with acute thrombus remains undetermined. Additionally, the clinical features of patients with chronic thrombus are largely unknown. Herein, we aimed to investigate the incidence and outcomes of patients with pulmonary embolism and chronic thrombus. This retrospective study included patients with pulmonary embolism from 2008 to 2016 at National Cheng Kung University Hospital. After excluding patients with tumor emboli or other etiologies and a lack of computed tomography images, we identified 205 patients with acute thrombus and 58 patients with chronic thrombus. Patients with chronic thrombus initially presented mainly with dyspnea, and the etiology was not related to recent surgery. Patients with chronic thrombus had a significantly higher incidence of elevated right ventricular systolic pressure detected by echocardiography and a higher incidence of subsequent events due to residual pulmonary embolism. Despite no differences in clinically recurrent pulmonary embolism, patients with chronic thrombus presented with a higher risk of all-cause and pulmonary embolism-related mortality than patients with acute thrombus. Chronic thrombus (hazard ratio: 2.03, p = 0.03), simplified pulmonary embolism severity index, anticoagulant use, and body mass index were the independent factors for all-cause mortality. Our findings suggest that using computed tomography pulmonary angiography for identifying patients with pulmonary embolism and chronic thrombus, which was associated with a higher risk of mortality, is pivotal for early intervention in addition to anticoagulant use.

Patient-Level, Institutional, and Temporal Variations in Use of Imaging Modalities to Confirm Pulmonary Embolism

Background:

The choice of the imaging modality for diagnosis of pulmonary embolism (PE) could be influenced by provider, patient or hospital characteristics, or over time. However, little is known about the choice of the diagnostic modalities in practice. The aim of this study was to evaluate the variations in the use of imaging modalities for patients with acute PE.

Methods:

Using the data from Registro Informatizado Enfermedad TromboEmbolica (RIETE), a prospective international registry of patients with venous thromboembolism (March 2001–January 2019), we explored the imaging modalities used in patients with acute PE. The imaging modalities included computed tomography pulmonary angiography, ventilation/perfusion scanning, pulmonary angiography, a combination of these tests, or PE signs and symptoms plus imaging-confirmed proximal deep vein thrombosis but no chest imaging.

Results:

Among 38 025 patients with confirmed PE (53.1% female, age: 67.3±17 years), computed tomography pulmonary angiography was the dominant modality of diagnosis in all RIETE enrollees (78.2% [99% CI, 77.6–78.7]); including pregnant patients (58.9% [99% CI, 47.7%–69.4%]) and patients with severe renal insufficiency (62.5% [99% CI, 59.9–65.0]). A greater proportion of patients underwent ventilation/perfusion scanning in larger hospitals compared with smaller hospitals (13.1% versus 7.3%, P <0.001). The use of computed tomography pulmonary angiography varied between 13.3% and 98.3% across the countries, and its use increased over time (46.5% in 2002 to 91.7% in 2018, P <0.001).

Conclusions:

In a large multinational PE registry, variations were observed in the use of imaging modalities according to patient or institutional factors and over time. However, computed tomography pulmonary angiography was the dominant modality of diagnosis, even in pregnancy and severe renal insufficiency. The safety, costs, and downstream effects of these tests on PE-related and non-PE-related outcomes warrant further investigation.

Percutaneous Thrombectomy in Emergency Department Patients with Pulmonary Embolism: The FLARE ED Sub-study

BACKGROUND

The FlowTriever Pulmonary Embolectomy Clinical Study (FLARE) was a multicenter, single-arm trial that demonstrated effectiveness of the FlowTriever percutaneous pulmonary embolectomy system in reducing right ventricular/left ventricular (RV/LV) diameter ratio in patients with acute intermediate-risk pulmonary embolism (PE). Patients diagnosed in emergency departments (EDs) with acute PE may have a different presentation from those diagnosed in an in-hospital setting.

OBJECTIVES

The goal of this sub-study was to evaluate the safety and effectiveness of mechanical embolectomy in ED patients with acute intermediate-risk PE.

METHODS

ED patients with acute PE and RV/LV ratio ≥ 0.9 enrolled in the FLARE study were core laboratory analyzed. The primary efficacy endpoint was the change in RV/LV ratio from baseline to 48 h post procedure. The change in RV/LV ratio of patients with nonelevated cardiac troponin (cTn) and zero simplified PE Severity Index (sPESI) score (normal cTn-sPESI: intermediate-low risk) was also examined. Major adverse events (MAEs) included major bleeding, device-related death or clinical deterioration, and vascular or cardiac injury.

RESULTS

Seventy-six ED patients were included. Thirty-nine had a sPESI score of ≥ 1 and 32 had elevated cTn. The median preprocedure RV/LV ratio for all ED patients was 1.50 (0.88-2.52), with a change by -0.37 postprocedure (p < 0.001.) Three patients experienced MAEs. Seventeen patients (22.4%) presented with normal cTn-sPESI and had an RV/LV ratio reduced by 0.27 (p < 0.001) after embolectomy.

CONCLUSION

ED patients with intermediate-risk PE had significant improvement in their RV/LV ratio and low complication rates when treated with mechanical embolectomy, irrespective of their baseline cTn-sPESI risk score.

Assessment of Acute Pulmonary Embolism by Computer-Aided Technique: A Reliability Study

Background

Acute pulmonary embolism is one of the most common cardiovascular diseases. Computer-aided technique is widely used in chest imaging, especially for assessing pulmonary embolism. The reliability and quantitative analyses of computer-aided technique are necessary. This study aimed to evaluate the reliability of geometry-based computer-aided detection and quantification for emboli morphology and severity of acute pulmonary embolism.

Material/Methods

Thirty patients suspected of acute pulmonary embolism were analyzed by both manual and computer-aided interpretation of vascular obstruction index and computer-aided measurements of emboli quantitative parameters. The reliability of Qanadli and Mastora scores was analyzed using computer-aided and manual interpretation.

Results

The time costs of manual and computer-aided interpretation were statistically different (374.90±150.16 versus 121.07±51.76, P<0.001). The difference between the computer-aided and manual interpretation of Qanadli score was 1.83±2.19, and 96.7% (29 out of 30) of the measurements were within 95% confidence interval (intraclass correlation coefficient, ICC=0.998). The difference between the computer-aided and manual interpretation of Mastora score was 1.46±1.62, and 96.7% (29 out of 30) of the measurements were within 95% confidence interval (ICC=0.997). The emboli quantitative parameters were moderately correlated with the Qanadli and Mastora scores (all P<0.001).

Conclusions

Computer-aided technique could reduce the time costs, improve the and reliability of vascular obstruction index and provided additional quantitative parameters for disease assessment.

Advances in the diagnosis of acute pulmonary embolism

Venous thromboembolism is a common disease which remains underdiagnosed because of nonspecific presentations which can range from asymptomatic incidental imaging findings to sudden death. Symptoms can overlap with comorbid cardiopulmonary disease, and risk factors that offer clues to the clinician are not always present. The diagnostic approach can vary depending on the specific clinical presentation, but ruling in the diagnosis nearly always depends on lung imaging. Overuse of diagnostic testing is another recognized problem; a cautious, evidence-based approach is required, although physician gestalt must be acknowledged. The following review offers an approach to the diagnosis of acute pulmonary embolism based on the assessment of symptoms, signs, risk factors, laboratory findings, and imaging studies.

Stress Hyperglycaemia Indicates Embolus Size and Localization in Patients with Acute Pulmonary Embolism

OBJECTIVE

Acute pulmonary embolism is a life-threatening form of venous thromboembolism often causing stress hyperglycaemia. The aim of this study was to determine the prognostic value of stress hyperglycaemia in acute pulmonary embolism, providing new insights into the presumed embolus size and localization, clinical parameters (Pulmonary Embolism Severity Index, PESI), and in-hospital mortality. Design and Methods. Among a total of 95,454 patients referred to the Emergency Department of the Sestre Milosrdnice University Hospital Centre between 2014 and 2016, all patients with acute pulmonary embolism were included into this observational cohort study. The study group consisted of 190 patients aged 25-96. Relevant patient history, clinical data, and laboratory findings were collected during the entire hospitalization period. Data were analyzed for the entire group of patients, as well as separately for patients without diabetes, using the Fisher exact test and logistic regression.

RESULTS

Analysis of embolus localization as an indirect parameter of embolus size showed that patients with stress hyperglycaemia more often had emboli located in proximal parts of the pulmonary circulation (i.e., main artery or lobar branches) (p < 0.05). Furthermore, stress hyperglycaemia correlated with PESI score and diabetes (p < 0.05) in the entire patient group. Stress hyperglycaemia showed independent association with in-hospital mortality in patients (p < 0.05).

CONCLUSION

Stress hyperglycaemia in patients with acute pulmonary embolism is associated with embolus localization in larger arteries of the pulmonary circulation and higher PESI score and therefore could serve as an independent in-hospital mortality predictor.

Fat embolism syndrome: Experience from an Australian trauma centre

BACKGROUND

Fat Embolism Syndrome (FES) is a rare condition where circulating fat emboli can lead to life threatening multisystem dysfunction. Diagnosis of FES occurs mainly by exclusion. The aim of this study was to describe the injury, event details, and factors associated with the diagnosis of FES following trauma presenting to a Level 1 Trauma Centre in Melbourne, Australia.

METHODS

Medical records of all patients with a complication of FES between 2006 and 2018 were retrospectively reviewed. Demographics, injury factors, hospital event details, radiological procedures and length of stay were collected.

RESULTS

Thirty six patients, with median age of 26 years (IQR 19, 42) and median Injury Severity Score (ISS) of 18.5 (IQR 10, 27) were diagnosed with FES. Other associated factors included male gender (86%) and having one or more long bone fractures (97%). Of the major FES diagnostic criteria, 94% of patients experienced hypoxia, 36% had mental status changes, whereas only 11% had petechiae. Computed Tomography Pulmonary Angiogram (CTPA) was performed on 19 patients (53%) with all being negative for pulmonary embolus. Most demonstrated ground glass opacity (58%), and FES was reported as the likely cause of patient presentation in 53% of cases.

CONCLUSION

FES following trauma was rare, with its diagnosis based on clinical factors including long bone fracture and hypoxia, and the exclusion of other respiratory diagnoses. CTPA was frequently used since 2008 and further research is warranted to determine if this radiological procedure can assist with more definitive diagnosis of FES.

The Results of Thrombolytic Treatment in Patients With High-risk Pulmonary Embolism

Background: Mortality rates due to massive pulmonary embolism (PE) are much higher than estimated. Although thrombolytic therapy is controversial, it can be a life-saving procedure and can be safely used in patients with massive PE.

Study aim: We aimed to share the results of thrombolytic treatment in patients with massive PE.

Material and methods: We retrospectively evaluated 72 patients with PE admitted between January 2010 and April 2018 to the Department of Pulmonary Medicine, VM Medicalpark Samsun Hospital, Samsun, Turkey. The data of patients who received thrombolytic treatment were retrospectively analyzed.

Results: The female to male ratio was 24/48, with a mean age of 62.7 ± 12.6 (minimum 27, maximum 88) years. The diagnosis of massive PE was established with echocardiography in all patients and was confirmed via pulmonary CT angiography in 45 patients (62.5%) who presented an appropriate clinical status for this imaging technique. The most common symptoms were dyspnea (90.3%), chest pain (83.3%), and syncope (40.2%). The S1Q3T3 electrocardiography pattern was noted in 82% of patients, who rapidly recovered after thrombolytic therapy. Cardiopulmonary arrest was seen in 25 patients (37.2%), and thrombolytic treatment was administered during cardiopulmonary resuscitation in 18% (n = 13) of patients. The survival rate was 30.7% (n = 4) in patients with cardiopulmonary arrest who received thrombolytic treatment in the emergency room. The complications of rt-PA treatment included minor hemorrhages in 6.4% (n = 5), major hemorrhages in 2.7% (n = 2), and allergic reactions in 1.3% (n = 1) of patients. None of the patients had deceased as a complication of thrombolytic treatment. The overall mortality rate was 26.2% (n = 19), and 12.5% (n = 9) of the patients have died in first 24 hours after thrombolysis.

Conclusions: We concluded that the risk factors, ECG, and echocardiography are key indicators for the suspicion of massive PE in patients with hemodynamic shock. Based on our experience, early thrombolytic therapy is a life-saving intervention in patients with diagnosed and/or suspected massive PE.

Early whole-body CT for treatment guidance in patients with return of spontaneous circulation after cardiac arrest

PURPOSE

Non-traumatic cardiac arrest (CA) and return of spontaneous circulation (ROSC) after cardiopulmonary resuscitation (CPR) are often associated with multiple pathologies. Expecting a high prevalence of important findings, a whole-body CT (WBCT) could be of relevance for therapy. The aim of this study is to investigate the feasibility and diagnostic yield of an early WBCT in this setting.

METHODS

This single-center retrospective study included 100 consecutive patients (27 female; 73 male; mean age 68.5± 12.57 years) with non-traumatic, in- and out-of-hospital CA and ROSC following CPR, who underwent a contrast-enhanced WBCT within 6 h after ROSC over 12 months. CT findings were determined corresponding to anatomical region.

RESULTS

Early WBCT was successfully carried out in 100% of the patients with CA and ROSC after CPR. Acute pathologies were found not only in the chest but also in the head (15%) and the abdomen (6%). Early global brain edema (n = 12), acute stroke (n = 3), pulmonary embolism (n = 10), pneumothorax (26%), acute abdominal pathologies (n = 6), iatrogenic bleeding (4%), and CPR-related injuries (93%) were detected by CT right from the beginning of the post-cardiac arrest care.

CONCLUSIONS

An early WBCT is feasible and provides added diagnostic value for patients with ROSC after non-traumatic CA.