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In recent years, the conjugation of superparamagnetic iron oxide nanoparticles (SPIONs), as tumor-imaging probes for magnetic resonance imaging (MRI), with tumor targeting peptides possesses promising advantages for specific delivery of MRI agents.(e objective of the current study was to design a targeted contrast agent forMRI based on Fe3O4 nanoparticles conjugated triptorelin (SPION@triptorelin), which has a great affinity to the GnRH receptors. (e SPIONs-coated carboxymethyl dextran (SPION@ CMD) conjugated triptorelin (SPION@CMD@triptorelin) were synthesized using coprecipitation method and characterized by DLS, TEM, XRD, FTIR, Zeta, and VSM techniques.(e relaxivities of synthetized formulations were then calculated using a 1.5 Tesla clinical magnetic field.MRI, quantitative cellular uptake, and cytotoxicity level of them were estimated.(e characterization results confirmed that the formation of SPION@CMD@triptorelin has been conjugated with a suitable size. Our results demonstrated the lack of cellular cytotoxicity of SPION@CMD@triptorelin, and it could increase the cellular uptake of SPIONs to MDA-MB-231 cancer cells 6.50-fold greater than to SPION@CMD at the concentration of 75 μM.(e relaxivity calculations for SPION@CMD@triptorelin showed a suitable r2 and r2/r1 with values of 31.75mM-1 ·s-1 and 10.26, respectively. Our findings confirm that triptorelin-targeted SPIONs could provide a T2-weighted probe contrast agent that has the great potential for the diagnosis of GnRH-positive cancer in MRI. [ABSTRACT FROM AUTHOR]

Introduction: There are some routine two-dimensional sequences, including short tau inversion recovery (STIR), T2-weighted fast-spin echo (T2W-FSE), and proton-density fast spin-echo for diagnosing osteoarthritis and lesions of the knee cartilage. However, these sequences have some disadvantages, such as long scan time, inadequate spatial resolution, and suboptimal tissue contrast which results in loss of image details, as well as missing the visualization of knee cartilage lesions. Three-dimensional (3D) sequences, such as the double-echo steady-state (DESS) sequence can decrease and overcome these problems to the smallest possible amount. Material and Methods: A total of 15 volunteers with knee pain were examined by a 1.5 Tesla magnetic resonance imaging. The contrast-to-noise ratio (CNR) and thickness values of the knee articular cartilage were measured. The CNR and thickness values were compared by the Friedman test and the Wilcoxon signed-rank test. Results: The obtained results showed significant differences between sequences in CNR and thickness values. The DESS sequence with a flip angle of 40°showed the best CNR values and 3D fast low-angle shot (FLASH) showed the worst results. In addition, the results showed no significant differences between FLASH, 3D DESS 40° and 90° in terms of cartilage thickness. However, thickness values of these sequences were much higher than that of the PD, T2, and STIR sequences. Conclusion: The 3D DESS sequence with two flip angles of 40°and 90° are the best sequences for visualizing the cartilage and the synovial fluid. Because they provide the best contrast between the cartilage and the synovial fluid, it is recommended to use DESS sequences in the evaluation of cartilage defections. [ABSTRACT FROM AUTHOR]

In recent years, the conjugation of superparamagnetic iron oxide nanoparticles (SPIONs), as tumor-imaging probes for magnetic resonance imaging (MRI), with tumor targeting peptides possesses promising advantages for specific delivery of MRI agents. The objective of the current study was to design a targeted contrast agent for MRI based on Fe 3 O 4 nanoparticles conjugated triptorelin (SPION@triptorelin), which has a great affinity to the GnRH receptors. The SPIONs-coated carboxymethyl dextran (SPION@CMD) conjugated triptorelin (SPION@CMD@triptorelin) were synthesized using coprecipitation method and characterized by DLS, TEM, XRD, FTIR, Zeta, and VSM techniques. The relaxivities of synthetized formulations were then calculated using a 1.5 Tesla clinical magnetic field. MRI, quantitative cellular uptake, and cytotoxicity level of them were estimated. The characterization results confirmed that the formation of SPION@CMD@triptorelin has been conjugated with a suitable size. Our results demonstrated the lack of cellular cytotoxicity of SPION@CMD@triptorelin, and it could increase the cellular uptake of SPIONs to MDA-MB-231 cancer cells 6.50-fold greater than to SPION@CMD at the concentration of 75  μ M. The relaxivity calculations for SPION@CMD@triptorelin showed a suitable r 2 and r 2 / r 1 with values of 31.75 mM -1 ·s -1 and 10.26, respectively. Our findings confirm that triptorelin-targeted SPIONs could provide a T 2 -weighted probe contrast agent that has the great potential for the diagnosis of GnRH-positive cancer in MRI., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2021 Milad Yousefvand et al.)