This is a Supine chest radiograph from the same patient. It was read as a possible small Pneumothorax on the lower left side of the plain film. However when viewed on CT Scan you can see that Pneumothorax is actually quite large. It is interior which is why it doesn't show up so well on the plain radiograph, but it is well visualized using sonography.
When we're looking at the Pleural line, we also want to look for artifacts. Here you can see some small tape ring Comet tail artifacts also known as Z lines and these are normal. However, when you look at the lung and you see these Comet tail artifacts which are long, hyperechoic or bright lines that go from the front of the probe face all the way to the back, these are known as B lines or Lung Rockets. And they're consistent with Alveolar interstitial syndrome which is typically congested heart failure in the acute setting which you may also see B lines with interstitial lung disease and other acute lung processes.
This clip shows the use of a linear probe also showing B lines with these hyperechoic lines going all the way from the Pleural line to the back of the screen.
If we're interested in looking for a Pleural effusion it's generally better to switch to the curvilinear probe, the penetrational view a little bit, the frequency is a bit lower. Again we check the orientation by putting a small amount of gel on the side of the indicator and confirming that this does indeed correspond to the left side of the screen as it is viewed.