Background: Nephrolithiasis is a common disease. It affects quality of life. Urinary calculi may be radiopaque or radiolucent on conventional radiography according to its composition. However, only radiopaque stones can be detected by fluoroscopy. Radiolucent stones can be localized by ultrasound (U/S) or using contrast media.

Aim: To evaluate different modalities localization of radiolucent stones during extracorporeal shock wave lithotripsy (ESWL) regarding efficacy, safety and cost-benefit.

Method: This prospective randomized clinical trial study included 48 patients presented to urology department by renal stones were treated by ESWL using electromagnetic Dornier lithotripter at Zagazig university hospital. Patients were divided into: Group (A) underwent ESWL on radiolucent renal stones, localized by U/S guidance and group (B) underwent ESWL on radiolucent renal stones, localized by fluoroscopy guidance by application of contrast media infused intravenously or through a ureteric catheter.

Result: There were no statistically significant differences (p>0.05) between U/S guided group and contrast guided group as regards stone free rate (SFR) after one ESWL session. There were no significant differences between the two treatment modalities regarding occurrence of complication (p>0.05). U/S guidance is more cost effective than contrast use.

Conclusion: U/S guidance has similar results to fluoroscopy with application of contrast media in localization of radiolucent renal stones during ESWL regarding SFR and complications. However, U/S has slightly better results and more cost effective than contrast fluoroscopy, U/S guidance is preferred due to the absence of radiation exposure.