A new technique for needle puncture to the renal calyx using contrast-enhanced ultrasonography (CE-US) with intracalyceal and intravenous injection of sonazoid®

Percutaneous entry is the initial and most important part of percutaneous nephrolithotomy (PCNL). Needle puncture directly into the fornix of a calyx is the safest route of percutaneous entry into the renal collecting system. An ultrasonic depiction of the dilated calyces can be easily obtained. However, when the pelvicalyceal system is not dilated, localization and puncture of the specific calyx may require special expertise. The present study investigated the usefulness and safety of contrast-enhanced ultrasonography (CE^-US) using Sonazoid® (Daiichi-Sankyo, Japan) in needle puncture to the renal calyx. Sonazoid® consists of an aqueous dispersion of lipid-stabilized perfluorobutane-filled gas microbubbles, which enables continuous observation of the target organs. All study protocols for this clinical investigation were approved of by the Ethical Review Board of Kurashiki Medical Center, and fully-informed consent regarding needle puncture to the renal calyx using CE-US with Sonazoid®was obtained from each patient prior to enrolment. The contrast agent Sonazoid^®was used intravenously and simultaneously injected intracalyceally through the instrument port of a flexible ureteroscope. This study used TOSHIBA Aplio MX ultrasonic diagnostic equipment (TOSHIBA Medical Systems, Japan). This machine sets out dual vision with real-time monitor mode (Sonazoid-mode, B-mode) simultaneously. Immediately after the intracalyceal injection of Sonazoid®, enhancement in the desired calyx and flow down to the ureter was observed. The needle was safely inserted between interlobar vessels, indicating the "Sonazoid stream", into the desired calyx in a single session. There were no adverse effects of the Sonazoid® administration. This new technique of needle puncture to the renal calyx with Sonazoid® is safe and effective, even when the pelvicalyceal system is not dilated.