Nephrography

Nephrography is the radiographic examination of the kidneys to assess anatomy and, in certain protocols, function. Historically, it referred to imaging after administration of contrast material, most notably intravenous urography (IVU), also called intravenous pyelography. In a typical nephrographic study, serial radiographs capture a nephrogram phase, in which the renal parenchyma enhances after contrast, followed by a pyelogram phase that delineates the calyces, pelvis, and collecting system as the contrast drains through the urinary tract. Related techniques include drip infusion nephrography, which uses a slow infusion of contrast to improve parenchymal visualization, and retrograde nephrography, in which contrast is injected directly into the collecting system via the ureter.

With advances in imaging, cross-sectional modalities such as CT urography and MR urography have largely supplanted conventional nephrography for many indications, offering superior anatomic detail and functional assessment with different contrast protocols. Nevertheless, nephrographic imaging remains a reference point in the history of renal radiology and is still encountered in certain contexts, especially in resource-limited settings or when CT or MRI is contraindicated.

Indications include evaluation of renal size and contour, detection of stones, assessment of hydronephrosis or other obstruction, masses, and overall renal function. Safety considerations center on exposure to ionizing radiation and risks related to iodinated contrast, including allergic reactions and contrast-induced nephropathy.