1. ¹Department of Neurology and Neurosurgery, Oregon Health and Science University, Portland, Oregon, USA
2. ²Portland Veterans Affairs Medical Center, Portland, Oregon, USA
3. ³Department of Radiology, Oregon Health and Science University, Portland, Oregon, USA
4. ⁴Department of Neurology, Oregon Health and Science University, Portland, Oregon, USA
5. ⁵Advanced Imaging Research Center, Oregon Health and Science University, Portland, Oregon, USA
6. ⁶Department of Radiology, Northwestern University, Chicago, Illinois, USA
7. ⁷Cancer Imaging Program, National Cancer Institute, SAIC-Frederick Inc., NCI-Frederick, Frederick, Maryland, USA
8. ⁸Department of Medicine, Oregon Health and Science University, Portland, Oregon, USA

Correspondence: Edward A. Neuwelt, Department of Neurology and Neurosurgery, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Mailcode L603, Portland, Oregon 97239, USA. E-mail: neuwelte@ohsu.edu

Received 10 April 2008; Revised 14 July 2008; Accepted 29 July 2008; Published online 8 October 2008.

Abstract

Gadolinium (Gd) based contrast agents (GBCAs) in magnetic resonance imaging (MRI) are used in daily clinical practice and appear safe in most patients; however, nephrogenic systemic fibrosis (NSF) is a recently recognized severe complication associated with GBCAs. It affects primarily patients with renal disease, such as stage 4 or 5 chronic kidney disease (CKD; glomerular filtration rate <30 ml/min per 1.73 m²), acute kidney injury, or kidney and liver transplant recipients with kidney dysfunction. Contrast-enhanced MRI and computed tomography (CT) scans provide important clinical information and influence patient management. An alternative contrast agent is needed to obtain adequate imaging results while avoiding the risk of NSF in this vulnerable patient group. One potential alternative is ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles, which provide enhancement characteristics similar to GBCAs. We review our experience in approximately 150 patients on the potential benefits of the USPIOs ferumoxtran-10 and ferumoxytol. We focus on central nervous system (CNS) MRI but also review imaging of other vascular beds. Safety studies, including USPIO administration (ferumoxytol) as iron supplement therapy in CKD patients on and not on dialysis, suggest that decreased kidney function does not alter the safety profile. We conclude that for both CNS MR imaging and MR angiography, USPIO agents like ferumoxytol are a viable option for patients at risk for NSF.