Improved dynamic response assessment for intra‐articular injected iron oxide nanoparticles

Abstract

The emerging importance of nanoparticle technology, including iron oxide nanoparticles for monitoring development, progression, and treatment of inflammatory diseases such as arthritis, drives development of imaging techniques. Studies require an imaging protocol that is sensitive and quantifiable for the detection of iron oxide over a wide range of concentrations. Conventional signal loss measurements of iron oxide nanoparticle containing tissues saturate at medium concentrations and show a nonlinear/nonproportional intensity to concentration profile due to the competing effects of T 1 and T 2 relaxation. A concentration calibration phantom and an in vivo study of intra-articular injection in a rat knee of known concentrations of iron oxide were assessed using the difference-ultrashort echo time sequence giving a positive, quantifiable, unambiguous iron signal and monotonic, increasing concentration response over a wide concentration range in the phantom with limited susceptibility artifacts and high contrast in vivo to all other tissues. This improved dynamic response to concentration opens possibilities for quantification due to its linear nature at physiologically relevant concentrations. Magn Reson Med 68:1544-1552, 2012. V C 2012 Wiley Periodicals, Inc.

Ultrasonic computed tomography imaging of iron oxide nanoparticles

“…The particles were later injected into various imaging phantoms (see section 2.4). The injected volume was designed so that the final dose at the target region was at the same range as the clinically attainable values and similar to previous studies (Al Faraj et al 2008, Crowe et al 2012, Arami et al 2015.…”

Syntheses of cross-linked polymeric superparamagnetic beads with tunable properties

“…Mass specic magnetic susceptibilities (k in m 3 kg À1 ) were measured with a Bartington MS3 magneto-susceptometer at 300 K with a MS2G mono frequency sensor at (1.3 kHz). T 2 signal loss and quantiable dUTE (difference ultrashort echo time) [28][29][30] Magnetic resonance imaging (MRI) measurements were done on the PVA-SPION@silica R i 9 on a Siemens Magnetom® Trio 3T with nanoparticle concentrations of up to 200 mg Fe mL À1 . The bio-interactions of PVA-SPION@silica R i 9 and R i 9* were studied using cytotoxicity assays with MTS assays and confocal microscopy on RAW 264.7 cells (mouse leukemic monocyte cell line).…”

Monitoring the effects of dexamethasone treatment by MRI using in vivo iron oxide nanoparticle-labeled macrophages

“…The quantitative method used here assessed the SPION intensity as an integral over the whole synovium. An additional advantage of dUTE is the suppression of all background signals providing contrast between SPION, bone and muscle [32]. Thus, easier segmentation is therefore possible and can be automated, avoiding false positives, unlike the signal loss from bone and ligament structure on T1-weighted MRI.…”

“…dUTE provides quantifiable SPION signal related to concentration [32]. Three-dimensional volume segmentation exploiting the contrast and monotonic signal/concentration correlation of dUTE allows unknown heterogeneous regions of iron oxide uptake to be assessed in disease models after systemic injection (custom software, Paracelsus Medical University, Salzburg, Austria).…”