Contrast nephrotoxicity and the role of radionuclide renal scan

Radiographic contrast media-induced nephrotoxicity is an important cause of acute renal failure. The indications of using contrast are usually unavoidable, compelling and continue to expand, especially in the vascular field. When acute renal failure follows such a procedure, it becomes important to establish the presence of contrast nephrotoxicity or an acute occlusive event which may have precipitated the failure. We present two cases of contrast nephrotoxicity in patients with impaired renal function. Radionuclide renal studies with 99mTc-DTPA (Patient 1) and 99mTc-MAG3 (Patient 2), confirmed the presence of acute tubular necrosis and excluded major occlusive vascular events. Renal scintigraphy remains an important but underused test which can rule out obvious renal vascular occlusion and/or support the diagnosis of contrast-related acute tubular necrosis, as the cause of renal failure in these patients.