Dynamic liver imaging with iron oxide agents: Effects of size and biodistribution on contrast

✍ Scribed by Joseph B. Mandeville; John Moore; David A. Chesler; Leoncio Garrido; Ralph Weissleder; Robert M. Weisskoff

• Book ID: 102956156
• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 609 KB
• Volume: 37
• Category: Article
• ISSN: 0740-3194
• DOI: 10.1002/mrm.1910370613

✦ Synopsis

Abstract

In vivo effective relaxation rates in normal rat liver were evaluated for four dextran coated iron oxide agents: monocrystal‐line iron oxide nanocolloid (MION) with a mean particle diameter of 3.9 nm, a polycrystalline agent (PION) with a larger mean diameter of 12 nm, and these two agents labeled with the asialofetuin (ASF) protein for high hepatocytic receptor binding affinity (MION‐ASF and PION‐ASF). Using echo planar imaging at 2 Tesla, dose response was measured with high temporal resolution for 3 h after injection of agent, and by comparing with relaxivities in vitro and in brain, dominant in vivo contrast phenomena were elucidated. While transverse relaxivity for PION‐ASF exceeded that for MION‐ASF by almost a factor of 2 in solution, relaxation rates in vivo became equivalent. Liver relaxation using non‐ASF agents was consistent with rapid water exchange between vascular and extravascular compartments, which dominated relaxation as a result of agent accumulation in Kupffer cells.