Carotid ultrasound is only useful for measuring stenosis > 50% The measurement of obstruction are based on the velocity (i.e. how fast) blood is flowing through a segment of the vessel. Think of it when a stream narrows, the water will flow faster through the narrow region.

Most likely with a 30% or even 50% stenosis, flow through that segment will be normal.

This comes down to semantics in the diagnostic report. If velocity is normal, some readers report that the vessel is "normal" although it may not be in terms of plaque present. I am not saying this is correct, but I have seen that before. The test is most useful to see if you need something done in terms of the degree of blockage.

I would speak with the physician that ordered the test to explain this to you.

Stephen J. Soldo