FIG 4. Transcranial Doppler sonogram, right transtemporal approach. After treatment, a twinkling artifact (arrow) is observed immediately behind the hyperechoic signal of the microcoil.

FIG 5. In vitro insonation of a Guglielmi detachable coil enclosed within two hydrated agar sheets. Color Doppler image shows the hyperechoic structure of the coil (arrow) and the twinkling artifact (arrowhead).