Subsegmental pulmonary embolism: value of thoracic ultrasound for diagnosis and follow-up

The wedge sign: A possible lung ultrasound sign for pulmonary thromboembolism

OBJECTIVE

To describe the finding of the lung ultrasound (LUS) "wedge sign" in dogs with presumptive pulmonary thromboembolism (PTE).

CASE SERIES SUMMARY

This case series describes 2 dogs with predisposing risk factors of (1) right transvenous pacemaker terminating in its right ventricle, severe protein-losing nephropathy, and glucocorticoid therapy, and (2) caval syndrome, each having the LUS "wedge sign" in upper lung regions, a sign consistent with pulmonary infarction and peripheral PTE.

NEW OR UNIQUE INFORMATION PROVIDED

Historically, the diagnosis of canine PTE has been made through supportive findings because the gold standard test, computed tomography pulmonary angiography (CTPA), poses limitations. The use of LUS has shown promise in people for detecting PTE, with the advantages of availability, being radiation- and contrast medium-sparing, rapid (<90 s), point-of-care, real-time information. Our cases suggest a possible new first-line approach for suspecting canine PTE by using LUS and the finding of the "wedge sign" in nongravity-dependent caudodorsal and perihilar lung regions.

Acute pulmonary thromboembolism in emergency room: gray-scale versus color doppler ultrasound evaluation

BACKGROUND

Pulmonary thromboembolism (PTE) remains under-diagnosed fatal disease at emergency units suggesting the need for alternative, easy, and noninvasive bedside diagnostic approaches.

OBJECTIVES

To determine the diagnostic role of gray-scale and color Doppler transthoracic ultrasonography (TUS) in patients with PTE.

PATIENTS AND METHODS

Blinded to 64 multi-detectors CT pulmonary angiography (MDCTPA) examination as a gold standard, 60 patients with clinically suspected PTE underwent gray-scale and then color Doppler TUS examination. Results were compared and diagnostic accuracy of TUS was assessed.

RESULTS

Forty patients proved to have PTE by MDCTPA. TUS showed typical lesions in 33 patients with the mean of 2 lesions per patient. Most lesions were hypoechoic, wedge- shaped, and pleural- based and the majority (80%) was located in the lower lobes. Consolidation with little perfusion was detected by Color Doppler ultrasound in 97% of lesions. Isolated central PTE was significantly higher in TUS negative patients. For gray -scale TUS, sensitivity, specificity, positive and negative predictive values and accuracy were 82%, 90%, 94%, 72%, and 85%. Meanwhile the sensitivity, specificity, positive and negative predictive values and accuracy of color Doppler TUS were 80%, 95%, 97%, 70% and 87%, respectively.

CONCLUSION

TUS is a reliable diagnostic bedside test for PTE in critically ill and immobile patients. Adding color Doppler to gray-scale TUS increases the specificity and accuracy and consequently the confidence in the diagnosis of peripheral pulmonary infarctions and differentiates them from other pulmonary lesions that allow initiation of anticoagulants.

Diagnostic validity of ultrasonography in evaluation of pulmonary thromboembolism

Background:

Diagnosis of pulmonary embolism (PE) remains difficult due to its nonspecific symptoms and signs. Therefore, many patients die undiagnosed or untreated. We decided to study the sensitivity, specificity, and accuracy of ultrasonography in the diagnosis of pulmonary thromboembolism.

Materials and Methods:

In this prospective study, 77 patients with clinically suspected PE in the emergency department of Isfahan Al-Zahra Hospital were enrolled from September 2011 to September 2012. At first, they were evaluated by thoracic ultrasonography (TUS) and then divided into four groups based on their TUS findings. Multi-slice computed tomography (MSCT) was the reference method in this study performed within 24 h from admission. MSCT scans were interpreted by a radiologist who was unaware of the TUS results. Sensitivity, specificity, positive predictive value (PPV), and negative predictive values (NPVs) of thoracic ultrasonography were determined.

Results:

PE diagnosis was confirmed by MSCT in 25 patients and 54 hypoechoic lesions were detected by TUS with the average size of 16.4 mm × 11.1 mm. In our study, sensitivity, specificity, PPV, NPV, and accuracy of TUS for PE diagnosis were 84%, 94.2%, 87.5%, and 92.5%, respectively.

Conclusion:

TUS is an inexpensive, safe and easily available method for timely diagnosis and treatment of PE in emergency department and its NPV is high for cases with low scores for Wells criteria who had a normal or possible TUS findings. It is also specific in the diagnosis of PE in cases with high scores Wells criteria who have confirmed or probable TUS findings.

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.