A pneumothorax is ruled out
Intercostal view – identifying structures
Costae
The costae are identified by the hypereechoic(white) surface and the anechoic (black) shadow below the costa.
Pleura
Pleura is seen as a hyperechogenic (white) structure between the costae.
Things are not always as they seem
OBSERVE: Image structures below the pleura line do not represent lung tissue – the air in the lungs absorbs the ultrasound waves and returns no echoes.
Structures seen in the image below the pleura line is not lung tissue but represent image artefacts from the echoes from the skin, muscle, costae and pleural line.
The linear ultrasound probe is placed on the skin surface over the sucutaneous fat layer, costae and intercostal muscles.
The lower part of the picture shows the ultrasound image of the tissue components of the chest wall.
Intercostal view – tips and tricks
Pleural line
If the pleural line and the lung signs cannot be clearly separated from the surrounding structures:
Posterolateral pleural view – identifying structures
In the posterolateral pleural view, the following structures can be seen:
Right side
Liver
Kidney (not seen in the image to the right)
Diaphragm
Spine
Left side
Spleen
Kidney
Diaphragm
Spine
B: Posterolateral pleural view on the left sideAL represents the area of the lung that is not visible because it is aerated.
Posterolateral pleural view – tips and tricks
Rotation
Generally, a slight rotation of the transducer, so the OM aims more towards the mattress, can improve image quality (counter-clockwise on right side, clockwise on left side).
Fluid follows gravity
Always make sure that the transducer is placed as posterior as possible – your hand needs to touch the mattress.
That hard left side
On the left side it is generally more difficult to obtain good images than on the right side – but the tips for optimising the image are the same:
The focused questions
At this point, you should feel confident about how to obtain the lung images.
If you do not feel confident, please review the slides.
If you do feel confident – now move on to answering the focused questions.
The focused questions in focused ultrasonography of the lungs are:
XX 1 – Learning objectives
Learning objectives for focused ultrasonography of the lungs
Obtain
– Anterior intercostal view (‘bat-sign’)
– Posterolateral pleural view
Answer the focused questions
– Can pneumothorax be confirmed or excluded?
– Are signs of pulmonary edema present or can pulmonary edema be excluded?
– Can pleural fluid be confirmed or excluded?
B: Anterior intercostal view with B-lines
C: Posterolateral pleural view with pleural fluid collection
The transducers for focused lung ultrasonography
A high frequency linear transducer or a curved (abdominal) transducer can be used for focused lung ultrasonography.
A linear high-frequency transducer is recommended if the purpose is only to visualise the pleural line (described later). The linear transducer has an optimal balance between resolution and depth for visualising superficial structures. It cannot be used for evaluating pleural fluid.
A lower-frequency transducer (abdominal or cardiac) permits the deep penetration that is needed for evaluation of pleural fluid (described later). The curved abdominal transducer also generates usable images for visualising the pleural line.
Tips
The ‘abdominal’ transducer can be used as an all-round transducer for focused lung ultrasonography.
Some cardiac transducers also allow fair imaging – but test your own equipment.
Right: Curved ‘abdominal’ transducer, optimal for evaluating pleural fluid but also works very well for visualising the pleural line.