What preprocedure preparation is required for the different urographic techniques?
Good-quality IVU requires preprocedural preparation, aimed at cleansing the colon so that overlying bowel contents do not obscure the upper urinary tract. Colon cleansing generally consists of laxatives taken the evening before the study. Patients are also asked to avoid solid food the day before the study and consume a clear liquid diet instead. In emergent situations, such as in the setting of a suspected ureteral leak, the study can be performed without preprocedural preparation, recognizing that the evaluation of the collecting systems for subtle abnormalities may be suboptimal without the bowel preparation. CTU requires neither a laxative preparation nor dietary modifications, making it the preferred technique for evaluation of the urinary tract.
For both CTU and MRU, normal renal function is a necessity. No special preprocedure preparation is required.