Sensitivity of single organ versus multiorgan point-of-care ultrasound compared to computed tomography pulmonary angiography in detecting pulmonary embolism in adult patients

Background: Pulmonary embolism (PE) is a serious and potentially life-threatening complication of venous thromboembolism and its diagnosis remains a challenge. The current gold standard to confirm diagnosis of PE is multi-row computed tomography pulmonary angiography (CTPA) but has limitations and alternative imaging modalities are being investigated. Point-of-care ultrasound (POCUS) has been applied in the diagnostic process in PE but whether it can safely replace the gold standard is of question. Methods: A literature review was conducted to evaluate the sensitivity of single versus multiorgan point-of-care ultrasound (POCUS) compared to CTPA in detecting PE in adult patients. Discussion: Several prospective observational studies exist investigating the use of single and multiorgan POCUS but are inconsistent in the selection of subjects, diagnostic reference tests used for comparison, criteria for PE diagnosis on POCUS and combinations of multiorgan POCUS used. A limited number of studies exist for each of the combinations of multiorgan POCUS investigated. Conclusion: Both single organ and multiorgan POCUS have shown inferior sensitivity to CTPA and cannot replace this diagnostic gold standard for PE. Triple multiorgan POCUS (lung, cardiac, and vascular) has shown the most promise thus far (sensitivity of 90%, specificity of 86%) and is recommended for patients that cannot receive CTPA and an adjunct to help provide alternative cardiopulmonary diagnoses, potentially reducing unnecessary radiographic imaging and may help to improve the prediction rules in stratifying risk for patients clinical suspicion of PE. More consistent research is needed to clarify the role and validity of POCUS in PE

Comparison of MRI and VQ-SPECT as a screening test for patients with suspected CTEPH: CHANGE-MRI study design and rationale

The diagnostic strategy for chronic thromboembolic pulmonary hypertension (CTEPH) is composed of two components required for a diagnosis of CTEPH: the presence of chronic pulmonary embolism and an elevated pulmonary artery pressure. The current guidelines require that ventilation–perfusion single-photon emission computed tomography (VQ-SPECT) is used for the first step diagnosis of chronic pulmonary embolism. However, VQ-SPECT exposes patients to ionizing radiation in a radiation sensitive population. The prospective, multicenter, comparative phase III diagnostic trial CTEPH diagnosis Europe - MRI (CHANGE-MRI, ClinicalTrials.gov identifier NCT02791282) aims to demonstrate whether functional lung MRI can serve as an equal rights alternative to VQ-SPECT in a diagnostic strategy for patients with suspected CTEPH. Positive findings are verified with catheter pulmonary angiography or computed tomography pulmonary angiography (gold standard). For comparing the imaging methods, a co-primary endpoint is used. (i) the proportion of patients with positive MRI in the group of patients who have a positive SPECT and gold standard diagnosis for chronic pulmonary embolism and (ii) the proportion of patients with positive MRI in the group of patients with negative SPECT and gold standard. The CHANGE-MRI trial will also investigate the performance of functional lung MRI without i.v. contrast agent as an index test and identify cardiac, hemodynamic, and pulmonary MRI-derived parameters to estimate pulmonary artery pressures and predict 6–12 month survival. Ultimately, this study will provide the necessary evidence for the discussion about changes in the recommendations on the diagnostic approach to CTEPH

Current diagnostic aspects on acute and chronic pulmonary embolism : MRI in acute pulmonary embolism, CT in chronic thromboembolic pulmonary hypertension and what the radiologists actually know

Background: Acute pulmonary embolism (APE) is a potentially severe medical condition with blood clots obstructing the pulmonary arterial vasculature. In most cases the APE resolves without any sequelae after anticoagulation therapy. In some patients, however, the emboli do not resolve upon treatment and the remnants cause increased vascular resistance, a condition known as chronic thromboembolic pulmonary hypertension (CTEPH). Both APE and CTEPH have a non-specific clinical presentation and imaging is an important part of the diagnosis. In APE computed tomography pulmonary angiography (CTPA) is the diagnostic gold standard, although the method is not suitable for all patients. CTPA has a high specificity for CTEPH, but the sensitivity remains under debate. At present CTPA is not recommended as a first line test among patients with a clinical suspicion of CTEPH. Purpose: To investigate unestablished imaging modalities in the diagnosis of APE (Study I) and CTEPH (Study III) including learning aspects (Study II) and knowledge (Study IV) of theses among radiologists. Regarding APE we studied magnetic resonance imaging (MRI) and in CTEPH we studied CTPA. Material and methods: Studies I-II were based on a prospective collection of 70 unenhanced MRI exams with CTPA as the gold standard. In Studies III-IV we used a retrospective material based on 43 CTPA exams from patients with confirmed CTEPH referred for presurgical assessment at a specialist centre, with a matched control with suspected APE. Results: All MRI exams were of diagnostic quality. Specificity was 100% for both readers and sensitivity 90% and 93% respectively with a nearly perfect inter-reader agreement (kappa 0.97) (Study I). Residents interpreting the MRI exams within the training program reached a clinically acceptable level after approximately 50 examinations and review time was halved during the training program (Study II). The sensitivity for CTEPH on CTPA reviewed by two experts was 100% and the specificity 100% (Study III), while the sensitivity based on the original reports from the same cases was 26% (Study IV). Conclusions: Unenhanced MRI has a high sensitivity and specificity for APE (Study I) and residents can learn to interpret such exams by using a self-directed training program (Study II). Enhanced CTPA has a high sensitivity when reviewed by experienced radiologists (Study III), but among radiologists in general the sensitivity is low (Study IV)

Using Topological Data Analysis for diagnosis pulmonary embolism

Pulmonary Embolism (PE) is a common and potentially lethal condition. Most patients die within the first few hours from the event. Despite diagnostic advances, delays and underdiagnosis in PE are common.To increase the diagnostic performance in PE, current diagnostic work-up of patients with suspected acute pulmonary embolism usually starts with the assessment of clinical pretest probability using plasma d-Dimer measurement and clinical prediction rules. The most validated and widely used clinical decision rules are the Wells and Geneva Revised scores. We aimed to develop a new clinical prediction rule (CPR) for PE based on topological data analysis and artificial neural network. Filter or wrapper methods for features reduction cannot be applied to our dataset: the application of these algorithms can only be performed on datasets without missing data. Instead, we applied Topological data analysis (TDA) to overcome the hurdle of processing datasets with null values missing data. A topological network was developed using the Iris software (Ayasdi, Inc., Palo Alto). The PE patient topology identified two ares in the pathological group and hence two distinct clusters of PE patient populations. Additionally, the topological netowrk detected several sub-groups among healthy patients that likely are affected with non-PE diseases. TDA was further utilized to identify key features which are best associated as diagnostic factors for PE and used this information to define the input space for a back-propagation artificial neural network (BP-ANN). It is shown that the area under curve (AUC) of BP-ANN is greater than the AUCs of the scores (Wells and revised Geneva) used among physicians. The results demonstrate topological data analysis and the BP-ANN, when used in combination, can produce better predictive models than Wells or revised Geneva scores system for the analyzed cohortComment: 18 pages, 5 figures, 6 tables. arXiv admin note: text overlap with arXiv:cs/0308031 by other authors without attributio

CT pulmonary angiography appropriateness in a single emergency department: does the use of revised Geneva score matter?

Purpose: To assess the percentage of computed tomography pulmonary angiography (CTPA) procedures that could have been avoided by methodical application of the Revised Geneva Score (RGS) coupled with age-adjusted D-dimer cut-offs rather than only clinical judgment in Emergency Department patients with suspected pulmonary embolism (PE). Material and methods: Between November 2019 and May 2020, 437 patients with suspected PE based on symptoms and D-dimer test were included in this study. All patients underwent to CTPA. For each patient, we retrospectively calculated the age-adjusted D-dimer cut-offs and the RGS in the original version. Finally, CT images were retrospectively reviewed, and the presence of PE was recorded. Results: In total, 43 (9.84%) CTPA could have been avoided by use of RGS coupled with age-adjusted D-dimer cut-offs. Prevalence of PE was 14.87%. From the analysis of 43 inappropriate CTPA, 24 (55.81%) of patients did not show any thoracic signs, two (4.65%) of patients had PE, and the remaining patients had alternative thoracic findings. Conclusion: The study showed good prevalence of PE diagnoses in our department using only physician assessment, although 9.84% CTPA could have been avoided by methodical application of RGS coupled with age-adjusted D-dimer cut-offs

Baffle thrombosis in an adult with remote prior scimitar vein repair mimicking massive pulmonary embolism

A 58-year-old man with a history of Scimitar syndrome diagnosed and surgically repaired in early adulthood presented multiple times to the emergency department complaining dyspnea, chest pain, and hemoptysis. Asymmetric pulmonary arterial flow rates between left and right lungs resulted in an apparent filling defect on computed tomographic pulmonary arteriography, which was repeatedly misdiagnosed clinically and radiologically as a massive pulmonary embolus. This case highlights the importance of understanding the pathophysiology and post-surgical complications of repaired congenital cardiovascular disease. Delayed phase acquisitions are often necessary to characterize the physiology of repaired congenital cardiovascular disease with associated shunts

Multimodality cardiovascular imaging in pulmonary embolism

Acute pulmonary embolism (APE) is one of the leading causes of cardiovascular (CV) morbidity andmortality. To select appropriate therapeutic strategy and/or to minimize the mortality and morbidity,rapid and correct identification of life-threatening APE is very important. Also, right ventricular (RV)failure usually precedes acute hemodynamic compromise or death, and thus the identification of RVfailure is another important step in risk stratification or treatment of APE. With advances in diagnosisand treatment, the prognosis of APE has been dramatically improving in most cases, but inadequatetherapy or recurrent episodes of pulmonary embolism (PE) may result in negative outcomes or, so called,chronic thromboembolic pulmonary hypertension (CTEPH). CTEPH is a condition characterized byremaining chronic thromboembolic material in the pulmonary vasculature and subsequent chronicpulmonary hypertension.Various imaging modalities include chest computed tomography pulmonary angiography (CTPA),echocardiography, magnetic resonance imaging, and nuclear imaging and each are used for the assessmentof varying status of PE. Assessment of thromboembolic burden by chest CTPA is the first step inthe diagnosis of PE. Hemodynamic assessment can be achieved by echocardiography and also by chestCTPA. Nuclear imaging is useful in discriminating CTEPH from APE.Better perspectives on diagnosis, risk stratification and decision making in PE can be provided bycombining multimodality CV imaging. Here, the advantages or pitfalls of each imaging modality indiagnosis, risk stratification, or management of PE will be discussed