Enhancement of Artifact

A and B, Transverse and sagittal planes, respectively, of the same volume shown in Figures 1–4. Enhancement of the ultrasound echo is noted below the endometrium (margins marked by arrows). The echo enhancement artifact is shown in coronal planes reconstructed at the anatomic level of the echo enhancement, as shown in Figure 1, B and C.

Enhancement is opposite of shadowing. It is the increase in reflection amplitude from reflectors being placed on the image with amplitudes that are too low and to hi9gh, respectively. In this situation, the echoes returning from structures deep to cyst appear more intense than if the cyst were not interposed. There are two explanations for the phenomenon. One is that the fluid replaces normal soft tissue in the intervening space, decreasing its attenuation. The time gain compensation (TGC) is set to expect tissue between the transducer and deepest echoes. If there is fluid instead, especially if the fluid occupies only the central portion of the image, the echoes returning from deep to the fluid collection will more intense than expected. This appears as a posterior enhancement of the beam, and this finding indicates that lesion is truly cystic, even if there are internal echoes with the cyst. Occasionally enhancement will be noted deep to a very small cystic structure, more than what can be explained by lack of attenuation. The small cyst acting as a lens and refocusing the sound beam may cause this enhancement. This is the opposite of refractive shadowing where the oblique interface defocuses the beam. Often the two coexist