The Shred Sign
As we have seen previously, lobar consolidations tend to be well-defined, often accompanied by a small pleural effusion. However, small subpleural consolidations (of course, ultrasound does not detect if they are not subpleural) are separated from the surrounding aerated lung by an irregular margin, like a torn paper called the ‘shred sign’. The brightness is because of the air, which scatters the ultrasound beam. It is also known as the fractal line. Here is an illustrative image.
Sometimes, the consolidation might appear anechoic mimicking a pleural effusion. But the presence of shred sign as in this example is specific to consolidation.
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