Magnetic resonance imaging of renal calculi: an in vitro study.

Extracorporeal shock wave lithotripsy (ESWL) has been established as a standard method of urinary stone treatment. Poor fragmentation with an increased rate of complications has been noticed with certain calculi types (calcium oxalate monohydrate and cystine). In devising appropriate pre-operative strategies, it would be useful to know the calculi composition. We have investigated the in vitro utility of using magnetic resonance imaging (MRI) in analyzing urinary calculi. Our in vitro analysis found no difference in signal characteristics between calculi of varying composition. The absence of signal can be understood from a molecular basis. We conclude that MRI will not offer any assistance in characterizing the composition of urinary calculi.