For renal/ureteric calculi, different guidelines have been adopted to select patients for their utmost benefit from ESWL. Although size of the calculus is one of the important parameters, it alone cannot be considered the sole determinant anticipating ESWL success.

Methods: From January 2014 to January 2015, 78 patients diagnosed with renal/ureteric calculi using non contrast computerised tomography scanners were included in the study. For disintegration of calculi, maximum energy level of 2, 2500 shocks for renal and 3000 shocks for ureteric calculi in each session, at a rate of 60 SWs/min for renal and 90 SWs/min for ureteric calculi was used. Stone clearance was assessed every 2 weeks using x–ray or ultrasonography, upto a maximum of 3 sessions. ESWL success was defined as attaining a stone–free status or presence of <3mm fragment on ultrasonography or no visible radio–opaque shadow on x–ray.

Results: Of the 78 patients, 42 had renal and 36 had ureteric calculi. In patients with renal calculi, the diameter of the stone (mm) varied from 4.8 – 17, HU 147 – 1543.8, SSD (cm) 4.71 – 15.24. For ureteric calculi, diameter varied from 4.4 – 14mm, HU 256.8 – 1244.6 HU, SSD 8.6 – 15.3 cm. We could demonstrate that, with increasing HU (over 1000) and SSD (over 10 cm), there was increase in the number of sessions required for fragmentation.

Conclusion: With the advent of NCCT, the patient with optimum stone characteristics, who can benefit the most can be categorised. In our study, HU < 1000 and SSD < 10 cm achieved faster stone free status.