T1-Weighted Ultrashort Echo Time Method for Positive Contrast Imaging of Magnetic Nanoparticles and Cancer Cells Bound With the Targeted Nanoparticles

• Type of Material: Article
• Authors: Longjiang Zhang, Emory University; Xiaodong Zhong, Siemens Healthcare; Liya Wang, Emory University; Hongwei Chen, Emory University; Y. Andrew Wang, Ocean NanoTech, LLC; Julie Yeh, Emory University; Lily Yang, Emory University; Hui Mao, Emory University
• Language: English
• Date: 2011-01
• Publisher: Wiley
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2010 Wiley-Liss, Inc.
• Final Published Version (URL): http://onlinelibrary.wiley.com/doi/10.1002/jmri.22412/abstract
• Title of Journal or Parent Work: Journal of Magnetic Resonance Imaging
• ISSN: 1053-1807
• Volume: 33
• Issue: 1
• Start Page: 194
• End Page: 202
• Grant/Funding Information: Contract grant sponsor: National Cancer Institute (NCI); Contract grant numbers: ICMIC, P50CA128301-01A10003, CCNE, U54 CA119338-01; Contract grant sponsor: EmTech Bio, Inc. This work is supported by Emory Molecular Translational Imaging Center with an in vivo Cellular and Molecular Imaging Center grant from National Cancer Institute (NCI) and Emory-Georgia Tech Nanotechnology Center for Personalized and Predictive Oncology with a grant of Center of Cancer Nanotechnology Excellence from NCI.; This work is supported by Emory Molecular Translational Imaging Center with an in vivo Cellular and Molecular Imaging Center grant from National Cancer Institute (NCI) and Emory-Georgia Tech Nanotechnology Center for Personalized and Predictive Oncology with a grant of Center of Cancer Nanotechnology Excellence from NCI.
• Keywords: molecular Imaging; magnetic nanoparticle; iron oxide; magnetic resonance imaging; ultrashort TE
• Research Categories: Health Sciences, Radiology

Abstract

Purpose To obtain positive contrast based on T1 weighting from magnetic iron oxide nanoparticle (IONP) using ultrashort echo time (UTE) imaging and investigate quantitative relationship between positive contrast and the core size and concentration of IONPs. Materials and Methods Solutions of IONPs with different core sizes and concentrations were prepared. T1 and T2 relaxation times of IONPs were measured using the inversion recovery turbo spin echo (TSE) and multi-echo spin echo sequences at 3 Tesla. T1-weighted UTE gradient echo and T2-weighted TSE sequences were used to image IONP samples. U87MG glioblastoma cells bound with arginine-glycine-aspartic acid (RGD) peptide and IONP conjugates were scanned using UTE, T1 and T2-weighted sequences. Results Positive contrast was obtained by UTE imaging from IONPs with different core sizes and concentrations. The relative-contrast-to-water ratio of UTE images was three to four times higher than those of T2-weighted TSE images. The signal intensity increases as the function of the core size and concentration. Positive contrast was also evident in cell samples bound with RGD-IONPs. Conclusion UTE imaging allows for imaging of IONPs and IONP bound tumor cells with positive contrast and provides contrast enhancement and potential quantification of IONPs in molecular imaging applications.