Ultra-small superparamagnetic iron oxide contrast agents for lymph node staging of high-risk prostate cancer

Abstract

Ultrasmall superparamagnetic particles of iron oxide (USPIOs) imaged with magnetic resonance imaging (MRI) have been proposed as an experimental method for visualizing lymph node (LN) metastases. The method does not require ionizing radiation, yet can detect small nodes that are involved with metastases. USPIOs are naturally taken up by macrophages that deposit in the normal LN creating a low signal region in normal areas; areas within the node that do not show this loss of signal are likely involved by tumor although there can be other causes (fibrosis or inflammation). However, the lack of approved USPIOs that are clinically available hinders adoption and larger studies. The proposed indications for USPIO MRI, including specific compounds and imaging methods are discussed.

Optimizing Dose and Timing in Magnetic Tracer Techniques for Sentinel Lymph Node Detection in Early Breast Cancers: The Prospective Multicenter SentiDose Trial

“…In a large patient dataset, it is now shown that a reduction down to half of the stipulated dose is highly effective and that a deeper preoperative injection yields more SLNs while retaining a high SPIO-RI concordance rate and resulting in less skin staining, when injected peritumorally. The use of SPIO in other clinical situations, such as SLN identification and dissection in malignant melanoma [ 31 ], prostate cancer [ 32 , 33 , 34 ], penile cancer [ 35 ] and uterine cancer [ 36 ], has been investigated, with interesting implementations.…”

Imaging diagnosis of metastatic breast cancer

“…Novel MRI contrast agents based on iron oxide and dendrimer nanomaterials allow for better characterisation of tumour metastases [112]. Particularly, ultrasmall superparamagnetic particles of iron oxide (USPIOs) imaged with MRI does not require ionising radiation, yet can detect small metastases [113]. The rationale for the use of USPIO is that, after intravenous injection, the nanoparticles are phagocytosed by macrophages in circulation which then enter the interstitial space and are taken up by lymphatics [114][115][116][117].…”

“…Finally, hybrid imaging techniques of combining WBMRI with 18 F-choline PET have recently showed to have a significantly higher sensitivity (93.5%) when compared to BS (63.6%) and WBMRI on its own (72.7%) [122]. The results are promising, but with limited access to PET-MRI and its high cost, a defined role of PET and newer advanced hybrid imaging techniques are needed [113]. Stratifying patients according to disease course and treatment status may prove beneficial in the future.…”

MRI-Tracking of Dental Pulp Stem Cells In Vitro and In Vivo Using Dextran-Coated Superparamagnetic Iron Oxide Nanoparticles

“…The signal loss could be observed in normal lymph nodes; however, in the areas that the lymph nodes were replaced by tumoral cells, less signal loss was visible due to less uptake of particles of iron oxide. The signal loss could be noted in the areas where iron oxide was presented [17]. SPIONs also enable various approaches, such as stem cell isolation, cell differentiation, cell patterning, and gene transfer.…”