Learning objectives
To review and illustrate thoracic ultrasound appearance of pneumothorax and learn a fast and easy method.
To describe the use of bedside sonography for excluding small pneumothorax in misdiagnose patients obtained with conventional radiography.
Background
Pneumothorax can quickly become a life threatening pathology,
and can be misdiagnose with the use of conventional chest films.
Supine AP chest radiograph used in critical ill patients,
pneumothorax misdiagnosis may occur up to 30% of all pneumothoraces.
Brook et all,
proved that eFAST exam shown 47 % of sensitivity to detect air within pleural space compared to a 16% of sensitivity in plain chest radiography.
Thoracic sonography also shown a 99% of specificity to discard pneumothorax with the use of convex probe.
Findings and procedure details
To help residents and young radiologist learn the use of thoracic ultrasound is necessary to know the basic ultrasound physics and the normal pulmonary signs.
Reverberation artifacts
The reverberation artifact is an horizontal or vertical image that occurs when ultrasound waves bounce between two interfaces with high acoustic impedance (pleura or interlobullar septae).
The waves moves up and down between these interfaces and the machine recognise them as parallel lines which have equal distances between them.
This artefact known as “A lines” represents multiple parallel...
Conclusion
Radiologist must learn the basic thoracic ultrasound examination to discard pneumothoraces in critical ill patients with an clinical suspicion or has recently performed a central venous catherization that the main complication is a pneumothorax.
Although ultrasound wave behaves very poorly within air,
in has shown that thoracic ultrasound is very sensitive and specific diagnostic test to detect small pneumothorax in a fast and easy way.
References
1.
Brook OR,
Beck-Razi N,
Abadi S,
et al.
Sonographic detection of pneumothorax by radiology residents as part of extended focused assessment with sonography for trauma.
J Ultrasound Med 2009; 28:749–755.
2.
Blaivas M,
Lyon M,
Duggal S.
A prospective comparison of supine chest radiography and bedside ultrasound for the diagnosis of traumatic pneumothorax.
Acad Emerg Med 2005; 12:844–849.
3.
Cunningham J,
Kirkpatrick AW,
Nicolaou S,
et al.
Enhanced recognition of “lung sliding” with power color Doppler imaging in the diagnosis of pneumothorax.
J Trauma...