[Treatment of calculi not easily seen with radiology using extracorporeal shockwave lithotripsy. Value of contrast media].

Currently, most calculi can be treated with shockwave extracorporeal lithotrity regardless their location within the urinary apparatus or their physico-chemical features. In order to optimize results only medical criteria for patient's selection should be taken into account. Certain type of calculi can obstruct adequate radioscopic viewing by not allowing correct centring for shockwave emission. The problem can be overcome by using echography or other contrast procedures. Of a total 514 patients treated in our Unit with ESWL, execution of contrast procedures was necessary in 18 cases (3.5%) in order to allow adequate viewing of the calculi. Calculi in 10 patients were midly radiopacque, uric acid in 4, and bone-superimposed in the remaining 4. This technical manoeuvre allowed in all cases a good centring of the calculi. After a two months follow-up. lithiasis is absent in 15 patients and only 2 present expellable lithiatic fragments. It can therefore be concluded that the use of contrast procedures, both through i.v. or a catheter, is a simple, safe and well tolerated procedure allowing convenient viewing of those calculi, also followed by good results after ESWL treatment.