IVU, an examination of the past without a future?

IVU has been gradually replaced over recent years as the "gold standard" in vestigation for the renal parenchyma and urinary tract by two new modalitie s: ultrasound and computed tomography. Some authors still advocate IVU for the assessment of renal colic, for the following reasons: the excess cost o f CT (which is not true for plain CT) and the absence of functional data (t here are specific CT signs for increased pressure). However the advantages of CT are clearly established: contrast resolution allowing the detection o f almost all stones except for certain complications of triple combination therapy in HIV seropositive patients, extensive cover facilitating identifi cation of differential diagnoses, rapidity and greater efficacy, and finall y the absence of risk related to the injection of iodinated contrast agents in this indication. However the performance of CT may be more limited in c ertain situations: thin patients, or when the female genital tract also nee ds to be investigated, but IVU is not more contributive in this context. Th e current place of IVU in renal colic is therefore to establish a definitiv e diagnosis and to guide an urgent procedure (removal of an obstruction in a context of infection) when CT is either unavailable (maintenance...) or r eally, excessively irradiating, as in pregnant women, when ultrasound, or e ven MRI and MR urography have not been sufficiently contributive. The essen tial indication remains detailed visualization of the urinary tract (assess ment of haematuria, detection of an urothelial tumour), detailed visualizat ion of the entire urinary tract (assessment of certain malformations), or e ven a gross assessment of renal function in a patient with multiple injurie s, which cannot be investigated by CT and in whom the surgeon rightly hesit ates before opening the retroperitoneum. However in the absence of IVU, we may fail to diagnose papillary necrosis or a small caliceal diverticulum, b ut is that really important in the final analysis? IVU, in countries with a dapted equipment, is therefore now only an expert examination. IVU is an ex amination of the past, without a future indeed, but with a descendant: CT u rography.