Allkemper Thomas, Bremer Christoph, Matuszewski Lars, Ebert Wolfgang, Reimer Peter
Department of Clinical Radiology, University Hospital Münster, Albert-Schweitzer-Strasse 33, 48129 Münster, Germany.
Radiology. 2002 May;223(2):432-8. doi: 10.1148/radiol.2232010241.
To investigate intravascular enhancement of bolus-injectable small and ultrasmall superparamagnetic iron oxides (USPIOs) of different particle sizes and relaxivities for first-pass and blood-pool magnetic resonance (MR) angiography.
Iron oxides with different particle sizes (hydrodynamic diameters, 21, 33, 46, and 65 nm) were bolus injected intravenously at three doses (10, 20, and 40 micromol per kilogram body weight). An extracellular contrast agent (gadopentetate dimeglumine) served as a control. MR angiography was performed multiple times after intravenous injection (5-120 minutes and 24 hours later). Signal enhancement was calculated from signal intensity measurements in the abdominal aorta and renal and iliac arteries.
Highest enhancement was seen during the first pass with all contrast agents. USPIO enhancement in the abdominal aorta increased significantly with decreasing particle size (65 nm vs 33 nm, 65 nm vs 21 nm; P <.01).
The smallest iron oxide provided signal enhancement comparable with that of gadopentetate dimeglumine at 40 micromol iron per kilogram for first-pass investigations, with prolonged signal enhancement up to 25 minutes, allowing multiple measurements after injection of a single bolus.
