Imaging for Vesicoureteral Reflux and Ureteropelvic Junction Obstruction. 
Although the imaging techniques used for diagnosing vesicoureteral reflux (VUR) and ureteropelvic junction obstruction (UPJO) are well determined, there is a need to decrease the numbers of unnecessary imaging and radiation exposure as most of the target population is children.  Newer imaging techniques are promising and could be eventually used for follow up in the near future.  To review the contemporary literature regarding the imaging techniques used for VUR and UPJO.  We conducted a nonsystematic review of the literature.  A comprehensive search was performed through PubMed database between 1980 (where maternal ultrasound [US] was first popularized) and 2015 focusing on the last decade.  Conventional US cannot replace voiding cystourethrography in the detection of VUR.  Contrast enhanced voiding sonography and direct radionuclide cystography suggest acceptable detection rates of VUR with sensitivity of 71-100% and specificity of 67-100%.  Renal US and diuretic radioisotope renography with choice of technetium99m mercaptocetyltriglycine are invaluable imaging modalities for the detection of UPJO.  Despite the concerns about the invasiveness and radiation exposure of conventional voiding cystourethrography, it is still the gold standard technique in the detection of VUR and is superior to the other options in depiction of anatomical details.  US and mercaptocetyltriglycine scintigraphy are also the gold standards and will continue to be so in the diagnosis of UPJO.  New imaging modalities such as contrast enhanced voiding sonography and direct radionuclide cystography are promising in the detection of vesicoureteral reflux.  Major effort in literature is given to decrease the radiation dose of the available imaging techniques.