Limits...
Nanoparticles in magnetic resonance imaging: from simple to dual contrast agents.

Estelrich J, Sánchez-Martín MJ, Busquets MA - Int J Nanomedicine (2015)

Bottom Line: Moreover, the signal-to-noise ratio can be improved with the acquisition of a large number of measurements.They can simultaneously bear both kinds of contrast and can, furthermore, incorporate targeting ligands and chains of polyethylene glycol to enhance the accumulation of nanoparticles at the site of interest and the bioavailability, respectively.Here, we review the most important characteristics of the nanoparticles or complexes used as MRI contrast agents.

View Article: PubMed Central - PubMed

Affiliation: Departament de Fisicoquímica, Facultat de Farmàcia, Universitat de Barcelona, Barcelona, Catalonia, Spain ; Institut de Nanociència I Nanotecnologia (IN UB), Barcelona, Catalonia, Spain.

ABSTRACT
Magnetic resonance imaging (MRI) has become one of the most widely used and powerful tools for noninvasive clinical diagnosis owing to its high degree of soft tissue contrast, spatial resolution, and depth of penetration. MRI signal intensity is related to the relaxation times (T 1, spin-lattice relaxation and T 2, spin-spin relaxation) of in vivo water protons. To increase contrast, various inorganic nanoparticles and complexes (the so-called contrast agents) are administered prior to the scanning. Shortening T 1 and T 2 increases the corresponding relaxation rates, 1/T 1 and 1/T 2, producing hyperintense and hypointense signals respectively in shorter times. Moreover, the signal-to-noise ratio can be improved with the acquisition of a large number of measurements. The contrast agents used are generally based on either iron oxide nanoparticles or ferrites, providing negative contrast in T 2-weighted images; or complexes of lanthanide metals (mostly containing gadolinium ions), providing positive contrast in T 1-weighted images. Recently, lanthanide complexes have been immobilized in nanostructured materials in order to develop a new class of contrast agents with functions including blood-pool and organ (or tumor) targeting. Meanwhile, to overcome the limitations of individual imaging modalities, multimodal imaging techniques have been developed. An important challenge is to design all-in-one contrast agents that can be detected by multimodal techniques. Magnetoliposomes are efficient multimodal contrast agents. They can simultaneously bear both kinds of contrast and can, furthermore, incorporate targeting ligands and chains of polyethylene glycol to enhance the accumulation of nanoparticles at the site of interest and the bioavailability, respectively. Here, we review the most important characteristics of the nanoparticles or complexes used as MRI contrast agents.

No MeSH data available.


Related in: MedlinePlus

T2-weighted contrasts and r2 color maps for iron oxide nanoparticles of different size.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4358688&req=5

f3-ijn-10-1727: T2-weighted contrasts and r2 color maps for iron oxide nanoparticles of different size.

Mentions: One important result of classical outer-sphere relaxation theory65 is that the r2/r1 ratio increases with increasing particle size, and thus, smaller particles are much better T1-shortening agents then larger ones (Figure 3).


Nanoparticles in magnetic resonance imaging: from simple to dual contrast agents.

Estelrich J, Sánchez-Martín MJ, Busquets MA - Int J Nanomedicine (2015)

T2-weighted contrasts and r2 color maps for iron oxide nanoparticles of different size.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4358688&req=5

f3-ijn-10-1727: T2-weighted contrasts and r2 color maps for iron oxide nanoparticles of different size.
Mentions: One important result of classical outer-sphere relaxation theory65 is that the r2/r1 ratio increases with increasing particle size, and thus, smaller particles are much better T1-shortening agents then larger ones (Figure 3).

Bottom Line: Moreover, the signal-to-noise ratio can be improved with the acquisition of a large number of measurements.They can simultaneously bear both kinds of contrast and can, furthermore, incorporate targeting ligands and chains of polyethylene glycol to enhance the accumulation of nanoparticles at the site of interest and the bioavailability, respectively.Here, we review the most important characteristics of the nanoparticles or complexes used as MRI contrast agents.

View Article: PubMed Central - PubMed

Affiliation: Departament de Fisicoquímica, Facultat de Farmàcia, Universitat de Barcelona, Barcelona, Catalonia, Spain ; Institut de Nanociència I Nanotecnologia (IN UB), Barcelona, Catalonia, Spain.

ABSTRACT
Magnetic resonance imaging (MRI) has become one of the most widely used and powerful tools for noninvasive clinical diagnosis owing to its high degree of soft tissue contrast, spatial resolution, and depth of penetration. MRI signal intensity is related to the relaxation times (T 1, spin-lattice relaxation and T 2, spin-spin relaxation) of in vivo water protons. To increase contrast, various inorganic nanoparticles and complexes (the so-called contrast agents) are administered prior to the scanning. Shortening T 1 and T 2 increases the corresponding relaxation rates, 1/T 1 and 1/T 2, producing hyperintense and hypointense signals respectively in shorter times. Moreover, the signal-to-noise ratio can be improved with the acquisition of a large number of measurements. The contrast agents used are generally based on either iron oxide nanoparticles or ferrites, providing negative contrast in T 2-weighted images; or complexes of lanthanide metals (mostly containing gadolinium ions), providing positive contrast in T 1-weighted images. Recently, lanthanide complexes have been immobilized in nanostructured materials in order to develop a new class of contrast agents with functions including blood-pool and organ (or tumor) targeting. Meanwhile, to overcome the limitations of individual imaging modalities, multimodal imaging techniques have been developed. An important challenge is to design all-in-one contrast agents that can be detected by multimodal techniques. Magnetoliposomes are efficient multimodal contrast agents. They can simultaneously bear both kinds of contrast and can, furthermore, incorporate targeting ligands and chains of polyethylene glycol to enhance the accumulation of nanoparticles at the site of interest and the bioavailability, respectively. Here, we review the most important characteristics of the nanoparticles or complexes used as MRI contrast agents.

No MeSH data available.


Related in: MedlinePlus