NephrologyTier 2Topic

Imaging - urograms

Role

CT urogram - multiphase CT (non-contrast, nephrographic, excretory/delayed phases) providing detailed anatomical imaging of the kidneys, collecting systems, ureters, and bladder in one study
Has largely replaced the older intravenous urogram (IVU/IVP) in most settings
Primary indication: investigation of haematuria (especially visible/unexplained) to assess the entire urothelium for stones, tumours, and structural abnormality

Phases

Non-contrast phase - detects stones (radiodense without needing contrast)
Nephrographic phase - renal parenchymal enhancement, masses
Excretory/delayed phase - contrast opacifies the collecting system and ureters, revealing filling defects (transitional cell carcinoma of the renal pelvis/ureter), strictures, or obstruction

Interpretation

A filling defect in the collecting system/ureter on the excretory phase raises concern for urothelial (transitional cell) carcinoma - requires cystoscopy +/- ureteroscopy for tissue diagnosis
Requires adequate renal function for contrast administration - a key limitation in CKD, where MR urography or non-contrast alternatives may be used instead

Place in the haematuria pathway

Central to the visible/unexplained haematuria pathway, performed alongside cystoscopy to cover the entire urinary tract (CT urogram - upper tract; cystoscopy - bladder/urethra)

Conditions

Urothelial carcinoma, nephrolithiasis, ureteric stricture, papillary necrosis

Harms

Radiation and contrast exposure (iodinated, nephrotoxicity risk) are the main limitations weighed against MR urography or ultrasound alternatives in vulnerable patients

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