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The properties of a superparamagnetic iron oxide (SPIO) model contrast agent have been studied. The test material, HEP-SPIO, contained iron oxide multicrystal agglomerates coated with heparin, polyanionic, naturally occurring glycosaminoglycan. Fractionation of the HEP-SPIO suspension showed the existence of colloidally stable particles ranging from approx.(More)
The in vitro contrast efficacy of liposome encapsulated gadolinium-[10-(2-hydroxypropyl)-1,4,7,10-tetraazacyclododecane-1, 4,7-triacetic acid] (GdHPDO3A) has been assessed by relaxometry. The internal concentrations were 150 and 250 mM Gd. Two types of liposome compositions were investigated: a phospholipid blend consisting of both hydrogenated(More)
SUPERPARAMAGNETIC CONTRAST AGENTS FOR MAGNETIC RESONANCE IMAGING Tueng Shen Submitted to the Harvard University-Massachusetts Institute of Technology Division of Health Sciences and Technology on April 29, 1994 in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Medical Engineering/Medical Physics Abstract Magnetic resonance(More)
The T2* contrast efficacy of paramagnetic contrast agents is dependent on their magnetic properties. Vibrating sample magnetometry (VSM) and the Live Chan NMR method have been used to evaluate the influence of ligand structure on the bulk magnetic susceptibility (BMS) of low-molecular weight (LMW) lanthanide chelates. VSM was also used for the BMS(More)
A new particulate magnetic resonance (MR) contrast agent was prepared by controlled precipitation of iron oxide in an aqueous starch solution. The potential of the magnetic starch microspheres (MSM) as a hepatosplenic contrast enhancer was studied by MR spectroscopy and MR imaging. Intravascular administration of MSM to rodents showed an effective blood(More)
Structure activity relationship (SAR) of superparamagnetic MR contrast agents is discussed based on physicochemical properties and relaxivity data of 16 different particles. All the magnetic particles reduce both relaxation times, T1 and T2. The effect on T2 is stronger than the effect on T1. The relaxation efficacy varies over a wide range. Minor(More)
RATIONALE AND OBJECTIVES Liposomal gadolinium (Gd)-HP-DO3A has been evaluated as a contrast agent for liver magnetic resonance imaging. The influence of various liposomal physicochemical properties on the liver uptake and contrast efficacy was investigated in various ex vivo and in vivo liver models. METHODS Liposomes of different size and membrane(More)
Gadolinium and dysprosium diethylenetriamine pentaacetic acid-labeled starch microparticles (Gd-DTPA-SP and Dy-DTPA-SP) were investigated as model liver contrast agents. The liver contrast efficacy of particles with low and high metal contents was compared in two imaging models: in vivo rat liver and ex vivo perfused rat liver. The biodistribution of(More)