ABSTRACT
Objective:Contrast enhanced ultrasound (CEUS) is an innovative technique that employs microbubble contrast agents to demonstrate parenchymal perfusion.Ultrasound contrast agent was reported to be directly used in human internal lumen to improve the observation capacity of ultrasound.However,CEUS has never been reported to be used in the guidance of percutaneous renal access in percutaneous nephrolithotomy (PCNL).This study aimed to assess the efficacy of CEUS-guided renal access in PCNL.Methods:In this retrospective study,percutaneous renal access was performed under real-time monitoring of CEUS during PCNL in a cohort of 20 patients with renal stones at Peking University First Hospital.Data regarding patients' demographic and clinical characteristics,therapeutic regimens,and postoperative information were collected from a comprehensive database containing comprehensive medical records of the patients undergoing PCNL.Briefly,the procedure was as follows.With the patient under general anesthesia,renal access was established by the guidance of CEUS.Afterwords,holmium laser,pneumatic or ultrasonic lithotripsy was used by the same urologist.The patient demographics,stone characteristics and procedure details were noted.Finally,appropriate statistical analyses were performed to evaluate the effectiveness and safety of the CEUS-guided percutaneous renal access in PCNL.Results:All the 20 patients underwent PCNL successfully with the help of CEUS guidance for tract creation.The collecting system was successfully accessed in all the patients,and only one patient underwent re-puncture.All the patients approached through a middle-pole percutaneous access.The median puncture time was 3.9 (2.9-4.6) min,and the median operating time was 112 (98.5-134.5) min.The preliminary stonefree rate of PCNL was 95.0％ (19/20) as shown by the kidney,ureter,and bladder (KUB) radiographs 48 h postoperation,and the median decline in hemoglobin level was 10 (5.5-14.5) g/L.Two patients had transient postoperative fever and responded well to antibiotics.In addition,no other major complications were observed.Conclusion:CEUS is a safe and effective alternative way of guidance for percutaneous renal access for PCNL beginners.It makes this procedure more visualized and simpler,and produces clearer images than common ultrasonic ones.PCNL beginners might benefit from this method to shorten the learning curve of PCNL,while it warrants further comparative studies to clarify.
ABSTRACT
Objective:To summarize the ultrasound features of renal arteriovenous fistula(RAVF)under various ultrasound imaging modes,so as to avoid missed diagnosis of RAVF on initial ultrasound examination.Methods:The clinical data of 6 patients with RAVF,including the ultrasound evidence,the timing of ultrasound diagnosis,the modes of ultrasound diagnosis, and the agreement between ultrasound diagnosis and selective renal arterial angiography,were retrospectively analyzed.Results: 2D ultrasound had 1 case of correct diagnosis,1 case of misdiagnosis and 4 cases of missed diagnosis.Color Doppler and spectral Doppler both had all the 6 cases correctly diagnosed.Ultrasound angiography in 3 cases demonstrated that the contrast agent reached the renal veins earlier than reached the renal parenchyma;large fistula lumen was associated with ischemia of downstream areas.3D ultrasound vividly reflected the structure of fistula lumen volume,and provided us with the profiles of blood signal in fistula at different planes and angles,improving our knowledge of blood flow on the fistula.Conclusion: Ultrasound is the first line screening method for RAVF.Color Doppler plays a decisive role in the diagnosis of RAVF and pulsed spectral Doppler plays a synergetic role and contributes to differential diagnosis.Contrast-enhanced ultrasound may help to discover the abnormality of venous circulation and the ischemic parenehyma area due to shunting.2D ultrasound has a poor diagnostic value and is liable to lead to misdiagnosis and missed diagnosis.