Feasibility of Retrograde Ureteral Contrast Injection to Guide Ultrasonographic Percutaneous Renal Access in the Nondilated Collecting System.
Ultrasound-guided percutaneous nephrolithotomy (PCNL) has become increasingly utilized. Patients with nondilated collecting systems represent a challenge: the target calix is often difficult to visualize. Here we report pilot study results for retrograde ultrasound contrast injection to aid in percutaneous renal access during ultrasound-guided PCNL.



From April to July 2016, consecutive patients over the age of 18 years with nondilated collecting systems on preoperative imaging who presented for PCNL were enrolled. B-mode ultrasound imaging was compared with contrast-enhanced mode with simultaneous retrograde injection of Optison™ via an ipsilateral ureteral catheter.



Five patients (four males and one female) with renal stones underwent PCNL with retrograde ultrasound contrast injection during the study period. Mean body mass index was 28.3 ± 5.6 kg/m2and mean stone size was 24.5 ± 12.0 mm. Under B-mode ultrasound, all patients demonstrated nondilated renal collecting systems that appeared as hyperechoic areas, where it was difficult to identify a target calix for puncture. Retrograde contrast injection facilitated delineation of all renal calices initially difficult to visualize under B-mode ultrasound. Renal puncture was then performed effectively in all cases with a mean puncture time of 55.4 ± 44.8 seconds. All PCNL procedures were completed without intraoperative complications and no adverse events related to ultrasound contrast injection occurred.



Retrograde ultrasound contrast injection as an aide for renal puncture during PCNL is a feasible technique. By improving visualization of the collecting system, it facilitates needle placement in challenging patients without hydronephrosis. Future larger scale studies comparing its use to standard ultrasound-guided technique will be required to validate this concept.
1 Department of Urology, University of California , San Francisco, San Francisco, California.|2 Division of Urology, Faculty of Medicine, King Chulalongkorn Memorial Hospital, Chulalongkorn University , The Thai Red Cross Society, Bangkok, Thailand .
Manint
M
Usawachintachit
1 Department of Urology, University of California , San Francisco, San Francisco, California.
David T
DT
Tzou
3 Department of Radiology and Biomedical Imaging, University of California , San Francisco, San Francisco, California.
John
J
Mongan
1 Department of Urology, University of California , San Francisco, San Francisco, California.|4 Department of Nephro-urology, Nagoya City University Graduate School of Medical Sciences , Nagoya, Japan .
Kazumi
K
Taguchi
3 Department of Radiology and Biomedical Imaging, University of California , San Francisco, San Francisco, California.
Stefanie
S
Weinstein
1 Department of Urology, University of California , San Francisco, San Francisco, California.
Thomas
T
Chi
D000328:Adult; D000368:Aged; D003287:Contrast Media / Q000008:administration & dosage*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007267:Injections; D007669:Kidney Calculi / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009403:Nephrostomy, Percutaneous / Q000379:methods*; D010865:Pilot Projects; D018084:Ultrasonography, Interventional / Q000379:methods*
D003287:Contrast Media
contrast-enhanced ultrasound; image-guided therapy; percutaneous nephrolithotomy; renal stone