[IVU: a test of the past without future?].

IVU has been gradually replaced over recent years as the "gold standard" investigation for the renal parenchyma and urinary tract by two new modalities: ultrasound and computed tomography. Some authors still advocate IVU for the assessment of renal colic, for the following reasons: the excess cost of CT (which is not true for plain CT) and the absence of functional data (there are specific CT signs for increased pressure). However, the advantages of CT are clearly established: contrast resolution allowing the detection of almost all stones except for certain complications of triple combination therapy in HIV seropositive patients, extensive cover facilitating identification of differential diagnoses, rapidity and greater efficacy, and finally 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 certain situations: thin patients, or when the female genital tract also needs to be investigated, but IVU is not more contributive in this context. The current place of IVU in renal colic is therefore to establish a definitive diagnosis and to guide an urgent procedure (removal of an obstruction in a context of infection) when CT is either unavailable (maintenance...) or really excessively irradiating, as in pregnant women, when ultrasound, or even MRI and MR urography have not been sufficiently contributive. The essential indication remains detailed visualization of the urinary tract (assessment of haematuria, detection of an urothelial tumour), detailed visualization of the entire urinary tract (assessment of certain malformations), or even a gross assessment of renal function in a patient with multiple injuries, which cannot be investigated by CT and in whom the surgeon rightly hesitates before opening the retroperitoneum. However, in the absence of IVU, we may fail to diagnose papillary necrosis or a small caliceal diverticulum, but is that really important in the final analysis? IVU, in countries with adapted equipment, is therefore now only an expert examination. IVU is an examination of the past, without a future indeed, but with a descendant: CT urography.