T₁ and T₂ Dual-Mode MRI Contrast Agent for Enhancing Accuracy by Engineered Nanomaterials

Abstract

One of the holy grails in biomedical imaging technology is to achieve accurate imaging of biological targets. The development of sophisticated instrumentation and the use of contrast agents have improved the accuracy of biomedical imaging. However, the issue of false imaging remains a problem. Here, we developed a dual-mode artifact filtering nanoparticle imaging agent (AFIA) that comprises a combination of paramagnetic and superparamagnetic nanomaterials. This AFIA has the ability to perform "AND logic gate" algorithm to eliminate false errors (artifacts) from the raw images to enhance accuracy of the MRI. We confirm the artifact filtering capability of AFIA in MRI phantoms and further demonstrate that artifact-free imaging of stem cell migration is possible in vivo.

Lanthanide Nanoparticles: From Design toward Bioimaging and Therapy

“…This concept of design was extended by changing the compositions of core and shell, and the ability to perform the "AND logic gate" algorithm to enhance the accuracy of the raw MR images was demonstrated. 258 A similar structure (Fe 3 O 4 @SiO 2 @Gd 2 O-(CO 3 ) 2 ) was reported by Luo and co-workers. 259 The effect of induced magnetic field on T 1 relaxation progress depends on the location of the T 1 contrast material.…”

Redoxable heteronanocrystals functioning magnetic relaxation switch for activatable T1 and T2 dual-mode magnetic resonance imaging

“…These agents work by shortening the traverse relaxation time (T 2 ) of water protons in their vicinity [11,12]. While they have high detection sensitivity for lesions, their magnetic susceptibility to artifacts and inherent negative (dark) contrast effects can induce low signal-to-noise ratios, which limits their application [13,14]. Consequentially, MR contrast agents that integrate both T 1 and T 2 contrast capabilities are highly desirable for advanced MR imaging techniques [14,15].…”

“…In this case, severe proton relaxation interference between the two different contrast agents (magnetic coupling), which attenuates the T 1 contrast effect by the strong local magnetic field of the superparamagnetic T 2 material, is inevitable when they are in close proximity to one another [15,16]. Several designs have demonstrated that inserting distance modulators between the T 1 and T 2 materials, such as silica shells [13,15] or inorganic linkers [16], can reduce the undesirable magnetic coupling effect. For those nanoplatforms, however, fastidious processing of the nanoparticles and well-defined DMCA design are required to avoid quenching the T 1 and T 2 contrast effects.…”

Fluorescent Heterodoped Nanotetrapods as Synergistically Enhancing Positive and Negative Magnetic Resonance Imaging Contrast Agents

“…One of these designs was based on the SPM core (T 2 ) and PM shell (T 1 ) structure with a spacer layer such as silica and platinum between them. Shin et al 22 used SiO 2 as spacer layer in their study and reported that 16 nm silica thickness is adequate between two magnetic materials to have high T 1 and T 2 signals. In addition, Cheng et al 23 synthesized hybrid nanotrimers obtained by combining T 1 iron oxide and Gd-coated Au nanocrystals separated by 5 nm platinum nanocubes.…”