ULTRASOUND CHARACTERISTICS OF SUBDERMALLY IMPLANTED IMPLANON(TM) CONTRACEPTIVE RODS

This study was designed to define sonographic characteristics and the optimal sonographic technique for localization of the single rod Impla non(TM) system. Diagnostic ultrasonography was performed in eight wome n who had the Implanon rod implanted in the medial aspect of the upper arm. All implants were scanned in the longitudinal and transverse dir ection using 3.5 MHz, 5 MHz, and 7.5 MHz linear array transducers. Sca nning was performed both directly against the skin and with 2 and 4 cm Kiteco(TM) ultrasound stand-off pads. Each image obtained was evaluat ed for detectability of the Implanon rod and the grade of acoustic sha dowing produced by the Implanon rod by two independent observers. Disc repancies in evaluation were adjudicated by a third observer. The Impl anon rod implant was not directly identified using the transducer and standoff pad combinations. Implanon rods were indirectly identified as a result of the posterior acoustic shadow cast by the Implanon. Best demonstration was achieved with the 5 or 7.5 MHz transducer and a 2 cm stand-off pad in the transverse direction. Appropriate ultrasonograph ic technique and familiarity with posterior acoustic shadowing pattern s generated by the implant provide a noninvasive method for localizati on of nonpalpable, single rod implants prior to removal. (C) 1997 Else vier Science Inc. All rights reserved.