Which Study When? Iodinated Contrast-enhanced CT Versus Gadolinium-enhanced MR Imaging

Abstract

Robert A. Halvorsen, MD Until 2006, conventional radiologic wisdom suggested that a patient with renal failure who needed a contrast material–enhanced study should undergo magnetic resonance (MR) imaging instead of computed tomography (CT). Patients with renal failure were at risk of developing contrast material– induced nephropathy (CIN) if given iodinated contrast material, but there was little or no known risk with contrast-enhanced MR imaging. However, since the description of nephrogenic systemic fibrosis (NSF) (1,2), a systemic disorder that occurs in some patients with renal failure who were given gadolinium-based contrast agents, the relative risks of CIN from iodinated contrast media compared to the relative risk of developing NSF from gadolinium-based agents have become unclear. Daily, radiologists are presented with a dilemma in patients with renal insufficiency. Which type of study should be performed? What type of contrast agent, if any, should be administered? This article will describe CIN and the multiple controversies related to CIN itself and CIN in comparison with NSF. The problems of contrast medium extravasation, allergic and allergic-type reactions, and the role of iodinated contrast media in the pregnant patient will also be discussed.