Gray scale echography of soluble protein and protein aggregate fluid collections (in vitro study).

Soluble protein fluid collections ranging from 0.5 to 21 gm/100 ml and collections of protein microaggregates with a particle size less than 700 microns are indistinguishable from water when these collections are examined qualitatively by gray scale echography in a laboratory setting. Echography of protein macroaggregate collections of 1-3 mm particle size gives rise to images showing strong internal echoes and poor margin definition and may simulate solid structures. Protein macroaggregates may be the source of error when complex biological fluids simulate solid lesions on gray scale echograms.