Persistent nephrogram

Persistent nephrograms occur when intravenous contrast media is retained by both kidneys for more than 3 minutes.

Terminology

Persistent nephrograms are characteristically bilateral and are usually distinguished from delayed nephrograms, which occur unilaterally.

Pathology

Etiology

• hypotension
  • can be a feature of CT hypoperfusion complex
• bilateral intrarenal obstruction, e.g. acute tubular necrosis, acute urate nephropathy
• vascular causes, e.g. bilateral renal artery stenosis, bilateral renal vein thrombosis
• bilateral obstructive uropathy