Simple device for determining an index of echogenicity

The technique reported here uses a simple electronic system adaptable to a standard manual echograph with the aim of obtaining a numerical index of echogenicity. The index is the ratio of the average echo amplitude within a gated portion of tissue at a given depth to the average echo amplitude within the same gated portion measured under the same conditions on a phantom filled with a "tissue-mimicking" material. A theoretical analysis shows that the index depends not only on the attenuation coefficient and the backscattering coefficient of the tissue but also on the depth of the measurement. It is demonstrated that it is feasible to measure the attenuation coefficient using the current system, and the reproducibility of the index measurement is evaluated on a normal thyroid.