Ancillary lung parenchymal findings at spiral CT scanning in pulmonary embolism. Relationship to chest sonography

Accuracy of transthoracic lung ultrasound for diagnosing pulmonary embolism: An updated systematic review and meta-analysis

BACKGROUND

Computed tomography pulmonary angiography (CTPA) simplifies the diagnosis of pulmonary embolism (PE) but is not suitable for all patients. Transthoracic lung ultrasound (LUS) is a potential alternative; this meta-analysis evaluates its accuracy for diagnosing PE.

METHODS

We systematically searched PubMed, Embase and Cochrane Library from the inception of each database up to April 2024 according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses of Diagnostic Test Accuracy Studies guidelines. Study quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 tool, and a bivariate random effects model was used to pool sensitivity and specificity.

RESULTS

A total of 18 studies with 2158 patients were analyzed. Lung ultrasound showed a sensitivity of 0.80 (95 %, confidence interval (CI): 0.71-0.86; I2 = 85.2 %) and specificity of 0.87 (95 %, CI: 0.81-0.92; I2 = 87.3 %). The diagnostic score was 3.27 (95 %, CI: 2.75-3.78; I2 = 61.9 %), and the diagnostic odds ratio was 26 (95 %, CI: 16-44; I2 = 100.0 %). The pooled positive likelihood ratio was 6.2 (95 %, CI: 4.2-9.1; I2 = 79.2 %), and the negative likelihood ratio was 0.24 (95 %, CI: 0.16-0.34; I2 = 83.7 %). The summary area under the curve was 0.91 (95 %, CI: 0.88-0.93). Significant heterogeneity was observed, which may impact the generalisability of the results, and no publication bias was detected.

CONCLUSION

Transthoracic LUS shows potential as an alternative to CTPA for PE diagnosis, but further research is needed to improve its accuracy and establish standardised diagnostic criteria. The observed heterogeneity highlights the need for a cautious interpretation of the results.

The Diagnostic Role of Lung Ultrasound and Contrast-Enhanced Ultrasound in Pulmonary Embolism

The diagnosis of pulmonary embolism (PE) relies essentially on a probabilistic approach that requires careful clinical assessments, targeted laboratory tests, and the use of appropriate imaging tools. Nowadays, the diagnostic gold standard is computed tomographic pulmonary angiography. Lung ultrasound (LUS) can play a role in the diagnosis of PE mainly by allowing the visualization of peripheral lung infarctions. Hypoechoic, pleural-based parenchymal consolidation is the most typical and common finding of pulmonary infarction. More than 85% of infarct lesions are wedge-shaped, extending to the pleural surface and are localized to where the patient complains of pleuritic chest pain. Contrast-enhanced ultrasound can be performed in addition to basic ultrasound examination to ascertain nonvascularization of the consolidation, thus confirming that the lesion is an infarct. The aim of this narrative review is to summarize the latest evidence on the application of LUS to the diagnosis of PE, focusing purely on thoracic/lung signs.

Incidence and Prognostic Role of Pleural Effusion in Patients with Pulmonary Embolism: A Systematic Review and Meta-Analysis

Background: Pleural effusion is a common pulmonary embolism (PE) complication, which has been documented to increase the risk of death in PE and relate to disease progression. However, the incidence of pleural effusion varies among studies and its association with PE outcome is still unclear. This study sought to determine the pooled incidence and prognostic value of pleural effusion events in patients with PE. Methods: We systematically searched the PubMed, EMBASE, SCOPE, Web of Science, Cochrane, LILACS, CINAHL, EBSCO, AMED, and OVID databases from the inception of each database to 7 September 2022 with a restriction on human studies, to identify studies assessing the association between pleural effusion and PE including all prospective and retrospective clinical studies. An exploratory meta-analysis was performed using a random-effects model. We evaluated the heterogeneity and performed subgroup analyses. Results: The final meta-analysis included 29 studies involving 13,430 PE patients. The pooled incidence of pleural effusion in PE patients was 41.2% (95% CI: 35.7–46.6%), which tended to be unilateral (pooled incidence: 60.8%, 95% CI: 45.7–75.8%) and small (pooled incidence: 85.9%, 95% CI: 82.6–89.1%). Pooled analysis using a random-effects model (I2 = 53.2%) showed that pleural effusion was associated with an increased risk of 30-day mortality (RR 2.19, 95% CI: 1.53–3.15, p < 0.001, I2 = 67.1%) and in-hospital mortality (RR 2.39, 95% CI: 1.85–3.09, p < 0.001, I2 = 37.1%) in patients with PE. Conclusions: Our meta-analysis found that PE patients had a high incidence of pleural effusion, which was usually unilateral and small. Pleural effusion generally increases 30-day and in-hospital mortality in patients with PE, and it is recommended that physicians be aware of the risk of death from PE, especially when patients have pleural effusion. Further investigations focusing on PE with pleural effusion are warranted.

Pulmonary Aspects of COVID-19

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a respiratory virus that gains entry via angiotensin-converting enzyme 2 (ACE2) within airway epithelium. Patients exhibit a spectrum of respiratory symptoms from asymptomatic to respiratory failure. Patient factors including obesity, tobacco use, and black race are all associated with increased ACE2 expression and may contribute to increased complications. Consolidation and ground-glass opacities on chest imaging are typical but not specific for coronavirus disease 2019 (COVID-19). Venous thromboembolism occurs infrequently when prophylactic anticoagulation is provided. However, capillary microthrombosis is nearly ubiquitous, suggesting that it contributes to hypoxemia. Remdesivir and glucocorticoids may benefit some hospitalized patients. Many of those afflicted remain symptomatic two weeks following diagnosis and continue to require health care. Total lung capacity, diffusion capacity, and maximal oxygen consumption may be reduced for months in some survivors. Lung transplant offers chronically critically ill patients new hope, and this option may have increasing potential for outpatients with COVID-19-associated fibrosis.

Diagnostic accuracy of focused deep venous, lung, cardiac and multiorgan ultrasound in suspected pulmonary embolism: a systematic review and meta-analysis

OBJECTIVE

To determine the diagnostic accuracy of point-of-care ultrasound in suspected pulmonary embolism.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

MEDLINE, Embase, CINAHL and Cochrane library were searched on 2 July 2020 with no restrictions on the date of publication. Subject headings or subheadings combined with text words for the concepts of pulmonary embolism, ultrasound and diagnosis were used.

ELIGIBILITY CRITERIA AND DATA ANALYSIS

Eligible studies reported sensitivity and specificity of deep venous, lung, cardiac or multiorgan ultrasound in patients with suspected pulmonary embolism, using an adequate reference-test. Prospective, cross-sectional and retrospective studies were considered for eligibility. No restrictions were made on language. Studies were excluded if a control group consisted of healthy volunteers or if transesophageal or endobronchial ultrasound was used. Risk of bias was assessed using quality assessment of diagnostic accuracy studies-2. Meta-analysis of sensitivity and specificity was performed by construction of hierarchical summary receiver operator curves. I² was used to assess the study heterogeneity.

MAIN OUTCOME MEASURES

The primary outcome was overall sensitivity and specificity of reported ultrasound signs, stratified by organ approach (deep venous, lung, cardiac and multiorgan). Secondary outcomes were stratum-specific sensitivity and specificity within subgroups defined by pretest probability of pulmonary embolism.

RESULTS

6378 references were identified, and 70 studies included. The study population comprised 9664 patients with a prevalence of pulmonary embolism of 39.9% (3852/9664). Risk of bias in at least one domain was found in 98.6% (69/70) of included studies. Most frequently, 72.8% (51/70) of studies reported >24 hours between ultrasound examination and reference test or did not disclose time interval at all. Level of heterogeneity ranged from 0% to 100%. Most notable ultrasound signs were bilateral compression of femoral and popliteal veins (22 studies; 4708 patients; sensitivity 43.7% (36.3% to 51.4%); specificity 96.7% (95.4% to 97.6%)), presence of at least one hypoechoic pleural-based lesion (19 studies; 2134 patients; sensitivity 81.4% (73.2% to 87.5%); specificity 87.4% (80.9% to 91.9%)), D-sign (13 studies; 1579 patients; sensitivity 29.7% (24.6% to 35.4%); specificity 96.2% (93.1% to 98.0%)), visible right ventricular thrombus (5 studies; 995 patients; sensitivity 4.7% (2.7% to 8.1%); specificity 100% (99.0% to 100%)) and McConnell's sign (11 studies; 1480 patients; sensitivity 29.1% (20.0% to 40.1%); specificity 98.6% (96.7% to 99.4%)).

CONCLUSION

Several ultrasound signs exhibit a high specificity for pulmonary embolism, suggesting that implementation of ultrasound in the initial assessment of patients with suspected pulmonary embolism may improve the selection of patients for radiation imaging.

PROSPERO REGISTRATION NUMBER

CRD42020184313.

European Respiratory Society statement on thoracic ultrasound

Thoracic ultrasound is increasingly considered to be an essential tool for the pulmonologist. It is used in diverse clinical scenarios, including as an adjunct to clinical decision making for diagnosis, a real-time guide to procedures and a predictor or measurement of treatment response. The aim of this European Respiratory Society task force was to produce a statement on thoracic ultrasound for pulmonologists using thoracic ultrasound within the field of respiratory medicine. The multidisciplinary panel performed a review of the literature, addressing major areas of thoracic ultrasound practice and application. The selected major areas include equipment and technique, assessment of the chest wall, parietal pleura, pleural effusion, pneumothorax, interstitial syndrome, lung consolidation, diaphragm assessment, intervention guidance, training and the patient perspective. Despite the growing evidence supporting the use of thoracic ultrasound, the published literature still contains a paucity of data in some important fields. Key research questions for each of the major areas were identified, which serve to facilitate future multicentre collaborations and research to further consolidate an evidence-based use of thoracic ultrasound, for the benefit of the many patients being exposed to clinicians using thoracic ultrasound.

Combining lung ultrasound and Wells score for diagnosing pulmonary embolism in critically ill COVID-19 patients

Subpleural consolidations have been found in lung ultrasound in patients with COVID-19, possibly deriving from pulmonary embolism (PE). The diagnostic utility of impact of lung ultrasound in critical-ill patients with COVID-19 for PE diagnostics however is unclear. We retrospectively evaluated all SARS-CoV2-associated ARDS patients admitted to our ICU between March 8th and May 31th 2020. They were enrolled in this study, when a lung ultrasound and a computed tomography pulmonary angiography (CTPA) were documented. In addition, wells score was calculated to estimate the probability of PE. The CTPA was used as the gold standard for the detection of PE. Twenty out of 25 patients met the inclusion criteria. In 12/20 patients (60%) (sub-) segmental PE were detected by CT-angiography. Lung ultrasound found subpleural consolidations in 90% of patients. PE-typical large supleural consolidations with a size ≥ 1 cm were detectable in 65% of patients and were significant more frequent in patients with PE compared to those without (p = 0.035). Large consolidations predicted PE with a sensitivity of 77% and a specificity of 71%. The Wells score was significantly higher in patients with PE compared to those without (2.7 ± 0.8 and 1.7 ± 0.5, respectively, p = 0.042) and predicted PE with an AUC of 0.81. When combining the two modalities, comparing patients with considered/probable PE using LUS plus a Wells score ≥ 2 to patients with possible/unlikely PE in LUS plus a Wells score < 2, PE could be predicted with a sensitivity of 100% and a specificity of 80%. Large consolidations detected in lung ultrasound were found frequently in COVID-19 ARDS patients with pulmonary embolism. In combination with a Wells score > 2, this might indicate a high-risk for PE in COVID-19.

Pleural effusion in acute pulmonary embolism in Bahrain: Radiological and pleural fluid characteristics

Background and Objectives

Pleural effusion is seen in around half of the cases of pulmonary embolism (PE). There are no data on the incidence of pleural effusion in cases of PE in the Kingdom of Bahrain. This study was done to determine the frequency and radiological features of pleural effusion in cases of acute PE and also to characterize the pleural fluid biochemistry and cell type in patients subjected to diagnostic thoracentesis.

Methods

This was a retrospective, observational single-center study. All the data of patients subjected to computed tomography pulmonary angiography (CTPA) in suspected cases of acute PE over a 4-year period were analyzed.

Results

A total of 1756 patients were subjected to CTPA from January 2013 to December 2016. A diagnosis of acute PE was made in 200 patients (11.4%). Pleural effusion was identified in 70 cases (35%). Majority of the effusions were small to moderate in size, bilateral, and associated with peripheral emboli. Consolidation, atelectasis, and ground glass attenuation were common associated findings on CTPA in these patients. Consolidation was more common in patients of PE associated with pleural effusion as compared to those with PE alone (62.85% and 33.8%, respectively, odds rato: 3.279 and 95% confidence interval: 1.798-6.091, P < 0.001). Diagnostic thoracentesis was done in 6 (8.6%) of the cases. All the patients had an exudative effusion with normal glucose values and neutrophil predominance.

Conclusion

PE was associated with pleural effusion in around one-third of the patients in Bahrain. The effusions were mainly small and bilateral. The emboli in cases associated with pleural effusion were mostly peripheral. Consolidation was the parenchymal abnormality detected on CTPA which was significantly associated with the presence of pleural effusion. Most of the pleural effusions were not suitable for thoracentesis. In patients subjected to fluid analysis, the effusions were exudative, neutrophilic predominant, and associated with normal glucose levels.

Detection of peripheral embolic consolidations using contrast-enhanced ultrasonography in patients with no evidence of pulmonary embolism on computed tomography: A pilot study

AIM

To investigate the value of B-mode imaging and contrast-enhanced ultrasonography (CEUS) in patients with clinically suspected pulmonary embolism (PE) but no evidence of central PE on CT.

METHODS

Between May 2004 and February 2015, we included in this retrospective study 19 patients with a risk profile for PE according to their Wells' score, sonographic patterns of peripheral embolic consolidations (EC) on B-mode-imaging and CEUS (ie, missing or inhomogeneous enhancement of the pleural lesions), and exclusion of central PE by CT within 1 week of CEUS.

RESULTS

On B-mode imaging, 19 pleural defects presented as hypoechoic. The shape of EC was round in 2, wedge-shaped in 12, polygonal in 3, and presented as atelectasis in 2 cases. On CEUS, 5 of the defects demonstrated, at the arterial and parenchymal phase, a lack of enhancement, and 14 showed an inhomogeneous (mixed) enhancement with wedge-shaped peripheral areas of no contrast enhancement. A second radiologic evaluation of the CT scans revealed PE in two patients and lesions suspicious for malignancy in two other patients.

CONCLUSIONS

Despite the lack of definite confirmation of peripheral and central PE on CT, peripheral pleural consolidations with no or inhomogeneous enhancement on CEUS, in combination with the risk profile for a PE, are highly suggestive of EC. If there is still some doubt, histologic confirmation is important to confirm EC and exclude malignancy. Thus, CEUS may close a potential diagnostic gap of small peripheral PE on CT. © 2017 Wiley Periodicals, Inc. J Clin Ultrasound 45:575-579, 2017.

Prognostic impact of pleural effusion in acute pulmonary embolism

Background Pulmonary embolism (PE) is a common and life-threatening condition associated with considerable morbidity and mortality. Pleural effusion occurs in about one in three cases; however, data on its prognostic value are scarce. Purpose To investigate the association between pleural effusion and both 30-day and long-term mortality in patients with acute PE. Material and Methods We retrospectively evaluated 463 patients diagnosed with acute PE using computed tomography pulmonary angiography (CTPA). Echocardiographic, demographic, and laboratory data were collected. The study population was divided into two groups: patients with and without pleural effusions. Pleural effusion detected on CT was graded as small, moderate, and large according to the amount of effusion. The predictors of 30-day and long-term total mortality were analyzed. Results Pleural effusions were found in 120 patients (25.9%). After the 30-day follow-up, all-cause mortality was higher in acute PE patients with pleural effusions than in those without (23% versus 9%, P < 0.001). Also, patients with pleural effusions had significantly higher incidence of long-term total mortality than those without pleural effusions (55% versus 23%, P < 0.001). In a multivariate analysis, pleural effusion was an independent predictor of 30-day and long-term mortality (odds ratio [OR], 2.154; 95% confidence interval [CI], 1.186-3.913; P = 0.012 and OR, 1.591; 95% CI, 1.129-2.243; P = 0.008, respectively). Conclusion Pleural effusion can be independently associated with both 30-day and long-term mortality in patients with acute PE.

Role of Transthoracic Lung Ultrasonography in the Diagnosis of Pulmonary Embolism: A Systematic Review and Meta-Analysis

Background

Pulmonary embolism (PE) is a potentially life-threatening condition. Although computed tomography pulmonary angiography (CTPA) is the reference standard for diagnosis, its early diagnosis remains a challenge, and the concerns about the radiation exposures further limit the general use of CTPA. The primary aim of this meta-analysis was to evaluate the overall diagnostic accuracy of transthoracic lung ultrasound (TLS) in the diagnosis of PE.

Methods

PubMed, Web of science, OvidSP, ProQuest, EBSCO, Cochrane Library and Clinicaltrial.gov were searched systematically. The quality of included studies was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 tool. The sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR) and hierarchical summary receiver operating characteristic (HSROC) curves were used to examine the TS performance. The Bayes analysis was used to calculate the post-test probability of PE. Publication bias was assessed with Deeks funnel plot.

Results

The results indicated that the sensitivity, specificity, PLR and NLR were 0.85 (95% confidence interval (CI), 0.78 to 0.90), and 0.83 (95% CI, 0.73 to 0.90). And the DOR and HSROC were 28.82 (95% CI, 17.60 to 47.21), 0.91(95% CI, 0.88, 0.93).

Conclusions

The present meta-analysis suggested that transthoracic lung ultrasonography is helpful in diagnosing pulmonary embolism. Although the application of transthoracic lung ultrasound may change some patients’ diagnostic processes, it is inappropriate to generally use transthoracic ultrasonography in diagnosing pulmonary embolism currently.

Ultrasonography for clinical decision-making and intervention in airway management: from the mouth to the lungs and pleurae

OBJECTIVES

To create a state-of-the-art overview of the new and expanding role of ultrasonography in clinical decision-making, intervention and management of the upper and lower airways, that is clinically relevant, up-to-date and practically useful for clinicians.

METHODS

This is a narrative review combined with a structured Medline literature search.

RESULTS

Ultrasonography can be utilised to predict airway difficulty during induction of anaesthesia, evaluate if the stomach is empty or possesses gastric content that poses an aspiration risk, localise the essential cricothyroid membrane prior to difficult airway management, perform nerve blocks for awake intubation, confirm tracheal or oesophageal intubation and facilitate localisation of tracheal rings for tracheostomy. Ultrasonography is an excellent diagnostic tool in intraoperative and emergency diagnosis of pneumothorax. It also enables diagnosis and treatment of interstitial syndrome, lung consolidation, atelectasis, pleural effusion and differentiates causes of acute breathlessness during pregnancy. Patient safety can be enhanced by performing procedures under ultrasound guidance, e.g. thoracocentesis, vascular line access and help guide timing of removal of chest tubes by quantification of residual pneumothorax size.

CONCLUSIONS

Ultrasonography used in conjunction with hands-on management of the upper and lower airways has multiple advantages. There is a rapidly growing body of evidence showing its benefits.

TEACHING POINTS

• Ultrasonography is becoming essential in management of the upper and lower airways. • The tracheal structures can be identified by ultrasonography, even when unidentifiable by palpation. • Ultrasonography is the primary diagnostic approach in suspicion of intraoperative pneumothorax. • Point-of-care ultrasonography of the airways has a steep learning curve. • Lung ultrasonography allows treatment of interstitial syndrome, consolidation, atelectasis and effusion.

Emergency ultrasound of the chest

Thoracic ultrasound is a noninvasive and portable diagnostic tool which is highly indicated for an initial workup of thoracic emergencies. The suspicion of a pneumothorax, pneumonia, pulmonary embolism or a lung contusion after trauma can be quickly assessed using ultrasound. Main advantages are its good availability and the steep learning curve. Another advantage of thoracic sonography is that this rapid, symptom-based examination has a high sensitivity and specificity. However, a disadvantage is that only pleura-affecting lesions or lesions visible through a sound window, e.g. an effusion or a subpleural consolidation, can be reached.

Diagnostic accuracy of lung ultrasound for pulmonary embolism: a systematic review and meta-analysis

BACKGROUND

Computed tomographic pulmonary angiography (CTPA) has simplified the diagnostic approach to patients with suspected pulmonary embolism (PE). However, PE diagnosis is still probabilistic and CTPA should be used with caution in some patient groups, such as patients with severe renal insufficiency and pregnant women. Among alternative imaging tests, lung ultrasound is the most promising technique. We aimed to systematically assess the diagnostic accuracy of lung ultrasound for PE diagnosis.

METHODS

Studies evaluating the diagnostic accuracy of lung ultrasound for the diagnosis of PE were systematically searched for in the MEDLINE and EMBASE databases (up to June 2012). The QUADAS-2 tool was used for the quality assessment of the primary studies. A bivariate random-effects regression approach was used for summary estimates of both sensitivity and specificity.

RESULTS

Ten studies, for a total of 887 patients, were included. A composite reference test was used in six studies, with single-row detector CTPA as the principal imaging test in four studies. Overall, seven studies used a proper reference test. Lung ultrasound bivariate weighted mean sensitivity was 87.0% (95% confidence interval [CI] 79.5, 92.0%), whereas bivariate weighted mean specificity was 81.8% (95% CI 71.0, 89.3%).

CONCLUSIONS

Our findings suggest that lung ultrasound may be a useful diagnostic tool in the management of patients with suspected PE. However, several methodological drawbacks of the primary studies limit any definite conclusion. Further well-designed accuracy studies are necessary before planning diagnostic management studies, in particular in those with a contraindication for CTPA.

The role of thoracic ultrasonography in the diagnosis of pulmonary embolism

OBJECTIVES:

The diagnosis of pulmonary embolism (PE) is still a problem especially at emergency units. The purpose of study was to determine the diagnostic accuracy of thoracic ultrasonography (TUS) in patients with PE.

METHODS:

In this prospective study, 50 patients with suspected PE were evaluated in Department of Pulmonary Diseases of a Training and Reasearch Hospital between January 2010 and July 2011. At the begining, TUS was performed by a chest physician, subsequently for definitive diagnosis computed tomography pulmonary angiography were performed in all cases as a reference method. Other diagnostic procedures were examination of serum d-dimer levels, echocardiography, and venous doppler ultrasonography of the legs. Both chest physician and radiologist were blinded to the results of other diagnostic method. Diagnosis of PE was suggested if at least one typical pleural-based/subpleural wedge-shaped or round hypoechoic lesion with or without pleural effusion was reported by TUS. Presence of pure pleural effusion or normal sonographic findings were accepted as negative TUS for PE.

RESULTS:

PE was diagnosed in 30 patients. It was shown that TUS was true positive in 27 patients and false positive in eight and true negative in 12 and false negative in three. Sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of TUS in diagnosis of PE for clinically suspected patients were 90%, 60%, 77.1%, 80%, and 78%, respectively.

CONCLUSIONS:

TUS with a high sensitivity and diagnostic accuracy, is a noninvasive, widely available, cost-effective method which can be rapidly performed. A negative TUS study cannot rule out PE with certainty, but positive TUS findings with moderate/high suspicion for PE may prove a valuable tool in diagnosis of PE at bedside especially at emergency setting, for critically ill and immobile patients, facilitating immediate treatment decision.

Thoracic ultrasound

Dyspnea and hypotension often present a diagnostic challenge to the emergency physician. With limitations on traditional methods of evaluating these patients, lung ultrasound has become an essential assessment tool. With the sensitivity of lung ultrasound approaching that of CT scan for many indications, it is quickly becoming a fundamental technique in assessing patients with thoracic emergencies. This article reviews the principles of thoracic ultrasound; describes the important evidence-based sonographic features found in pneumothorax, pleural effusion, pneumonia, and pulmonary edema; and provides a framework of how to use thoracic ultrasound to aid in assessing a patient with severe dyspnea.

Ancillary findings on CT pulmonary angiograms and abnormalities on chest radiographs in patients in whom pulmonary embolism was excluded

To determine whether chest radiographs identify some abnormalities not shown as ancillary findings on computed tomography(CT) pulmonary angiograms of patients in whom pulmonary embolism (PE) was excluded. This was a retrospective study of reports of negative 64-detector CT pulmonary angiograms and chest radiographs. Among 332 patients with no PE, pulmonary parenchymal disease was shown in 60 (18%) only on standard chest radiographs, and pleural or pericardial disease was shown in 17 (5%) only on chest radiographs. Skeletal abnormalities were reported more frequently on standard chest radiographs, lymph nodes more frequently on CT angiograms. Some abnormalities on chest radiographs of patients in whom PE is excluded may not be described as ancillary findings on CT pulmonary angiograms. This suggests a need for ancillary findings on CT pulmonary angiograms to be described systematically. At present, however, plain chest radiographs in some patients show ancillary findings not reported on CT angiograms. [corrected].

Current role of emergency ultrasound of the chest

OBJECTIVE

Chest sonography has gained clinical significance in the diagnosis of various pulmonary, pleural, cardiac, and mediastinal emergency conditions. Therefore, the current role of emergency ultrasound are assessed.

DATA SOURCE

A systematic literature search of MEDLINE database was performed to identify all studies dealing with transthoracic sonography/chest ultrasound in combination with pulmonary embolism, pneumothorax, pneumonia, pleural effusion, pulmonary edema, and lung contusion. The relevant sonographic studies between 1988 and 2010 were evaluated.

CONCLUSIONS

The noninvasive ultrasound-based diagnosis is relatively portable permitting the technique to be performed at any time, in any place, and on any patient, an ideal method for emergency conditions. Sonography allows immediate diagnosis of pulmonary embolism, pneumothorax, pneumonia, pleural effusion as well as rib fracture, and it provides a basis for further diagnostic- and treatment-related decisions. The key sonographic features associated with these most common emergency chest diseases are illustrated herein.

Is It possible to recognize pulmonary infarction on multisection CT images?

PURPOSE

To retrospectively determine sensitivity and specificity of four findings for distinguishing pulmonary infarction from other causes of peripheral pulmonary consolidations on multidetector computed tomographic (CT) images, with other CT and clinical findings as reference.

MATERIALS AND METHODS

Institutional review board approved the study and waived informed consent. Three independent radiologists blindly analyzed selected multisection CT images of 50 pulmonary infarctions-not showing direct arterial signs of pulmonary embolism-and 100 peripheral consolidations of other origins. Readers analyzed four findings: triangular shape, vessel sign (defined as presence of an enlarged vessel at the apex of consolidation), central lucencies, and air bronchograms. Interobserver agreement; frequency on CT images with and without infarct; and sensitivity, specificity, and positive likelihood ratio (LR) for diagnosis of pulmonary infarction were assessed for each finding.

RESULTS

One hundred fifty peripheral consolidations were analyzed in 134 (75 men, 59 women) patients (mean age, 55.9 years+/-17.4 [standard deviation] vs 54.7+/-19.9; P=.71). Interobserver agreement was good for central lucencies and air bronchograms and poor to moderate for the other two findings (kappa<0.61). Compared with CT images without infarct, CT images with infarct had a higher frequency of vessel sign (32% [16 of 50] vs 11% [11 of 100], P=.029) and central lucencies (46% [23 of 50] vs 2% [two of 100], P<.001) and a lower frequency of air bronchograms (8% [four of 50] vs 40% [40 of 100], P=.003). Frequency of triangular shape was similar in both groups (52% [26 of 50] vs 40% [40 of 100], P=.17). Positive LR was 23.0 for central lucencies, 2.9 for vessel sign, 1.3 for triangular shape, and 0.2 for air bronchograms. Presence of central lucencies had 98% specificity and 46% sensitivity for pulmonary infarction. When the vessel sign and negative air bronchogram were combined with central lucencies, specificity increased to 99% but sensitivity decreased to 14%.

CONCLUSION

Central lucencies in peripheral consolidations are highly suggestive of pulmonary infarction.

Analysis of pleural effusions in acute pulmonary embolism: Radiological and pleural fluid data from 230 patients

BACKGROUND AND OBJECTIVE

The aims of this study were to describe the frequency and radiographical characteristics of pleural effusions in a large population of patients with acute pulmonary embolism (PE) and characterize the pleural fluid biochemistry in those patients who underwent diagnostic thoracentesis.

METHODS

This was a retrospective observational single-centre study. A total of 230 consecutive patients with a diagnosis of PE over a 9-year period were enrolled. Spiral CT pulmonary angiography (52%) and high-probability ventilation and perfusion scans (42%) were used as the main reference methods.

RESULTS

Pleural effusions were observed in 32% and 47% of patients by CXR and CT, respectively. Typically, pleural effusions were small (90% occupied less than one third of the hemithorax) and unilateral (85%), but occasionally they reached more than a half of the hemithorax. On CT, 21% of pleural effusions showed loculation. In patients with loculated pleural fluid the diagnosis of PE had been delayed for a mean of 12.2 days after symptoms developed. The presence of pleural fluid was not related to infarction. Twenty-six of 93 (28%) patients with effusions on imaging underwent thoracentesis. All the fluids met Light's criteria for exudate, 58% contained erythrocyte counts >10,000/microL and 46% showed neutrophilic predominance.

CONCLUSIONS

Small pleural effusions, mostly unsuitable for diagnostic thoracentesis, were present in about one third of patients with PE. All the pleural effusions due to PE were exudates. If PE diagnosis was delayed the pleural effusion tended to become loculated.

Thoracic ultrasound for diagnosing pulmonary embolism: a prospective multicenter study of 352 patients

BACKGROUND

Pulmonary embolism (PE) continues to be a major challenge in terms of diagnosis, as evidenced by the fact that many patients die undiagnosed and/or untreated. The aim of this multicenter study was to determine the accuracy of thorax ultrasound (TUS) in the diagnosis of PE (TUSPE).

METHODS

From January 2002 through September 2003, 352 patients with suspected PE were examined in seven clinics. The patients were investigated prospectively by TUS according to the following criteria: (1) PE confirmed: two or more typical triangular or rounded pleural-based lesions; (2) PE probable: one typical lesion with pleural effusion; (3) PE possible: small (< 5 mm) subpleural lesions or a single pleural effusion alone; or (4) normal TUS findings. In all cases, CT pulmonary angiography (CTPA) was used as the reference method. In the event of discrepant findings, a combination of duplex sonography of the leg veins, echocardiography, ventilation/perfusion scintigraphy, and a quantitative enzyme-linked immunosorbent assay or latex d-dimer, or a biopsy/autopsy was performed.

FINDINGS

PE was diagnosed in 194 patients. On TUS, 144 patients had a total of 333 subpleural lesions (mean, 2.3 lesions per patient) averaging 15.5 x 12.4 mm in size. Additionally, a narrow pleural effusion was found in 49% of the patients. TUS yielded the following results under application of the strict criteria 1 and 2: PE true-positive, n = 144; PE false-positive, n = 8; PE true-negative, n = 150; and PE false-negative, n = 50. The sensitivity was 74%, specificity was 95%, positive predictive value was 95%, negative predictive was value 75%, and accuracy was 84%, at a prevalence of 55%. The sensitivity in patients with criterion 1 was 43% and a specificity of 99%.

INTERPRETATION

TUS is a noninvasive method to diagnose peripheral PE. In the absence of CTPA, TUS is a suitable tool to demonstrate a PE at the bedside and in the emergency setting.

CT Scan Findings in Chronic Thromboembolic Pulmonary Hypertension

STUDY OBJECTIVES

The aim was to correlate CT scan findings with hemodynamic measurements in patients who had undergone pulmonary thromboendarterectomy (PTE) and to evaluate whether CT scan findings can help to predict surgical outcome.

PATIENTS AND METHOD

Sixty patients who underwent PTE and preoperative helical CT scanning were included. Preoperative and postoperative hemodynamics were correlated with preoperative CT imaging features.

RESULTS

The diameter of the main pulmonary artery (PA) and the ratio of the PA and the diameter of the ascending aorta correlated with preoperative mean pulmonary artery pressure (PAP) [r = 0.42; p < 0.001; and r = 0.48; p < 0.0001, respectively]. There was a significant correlation of subpleural densities with preoperative pulmonary vascular resistance (PVR) [r = 0.44; p < 0.001] and of the number of abnormal perfused lobes with preoperative PAP (r = 0.66; p < 0.0001) and PVR (r = 0.76; p < 0.0001). Postoperative PVR correlated negatively with the presence and extent of central thrombi (r = -0.36; p = 0.007) and dilated bronchial arteries (p = 0.03) seen on preoperative CT scans. Sixty percent of patients (3 of 5 patients) without visible central thromboembolic material on CT scans had an inadequate hemodynamic improvement in contrast to 4% of patients (2 of 51 patients) with central thrombi (p = 0.003). Preoperative PVR (r = 0.31; p = 0.018) and the extent of abnormal lung perfusion (r = 0.37; p = 0.007) and of subpleural densities (r = 0.32; p = 0.017) were positively correlated with postoperative PVR.

CONCLUSIONS

In patients with thromboembolic pulmonary hypertension, CT scan findings can help to predict hemodynamic improvement after PTE. The absence of central thrombi is a significant risk factor for inadequate hemodynamic improvement.