Enzyme‐responsive PARACEST MRI contrast agents: a new biomedical imaging approach for studies of the proteasome

Yoo, Byunghee; Raam, Manu S.; Rosenblum, R.; Pagel, Mark

doi:10.1002/cmmi.145

Cited by 77 publications

(74 citation statements)

References 38 publications

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“…These findings further add to the field of CEST agents beyond the outstanding achievements of their use as metabolic reporting agents (16)(17)(18)(19)(20). À as the hydrophilic shift reagent and with a DPPC-DSPE-PEG2000 (95:5 in moles) as the membrane formulation.…”

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confidence: 90%

First ex‐vivo MRI co‐localization of two LIPOCEST agents

Terreno

Castelli

Milone

et al. 2008

Contrast Media & Molecular

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One of the major advantages of the CEST methodology deals with the possibility of visualizing more probes in the same MR image voxels. This is a unique property within the contrast media that act on the (1)H-NMR signal of water protons, and it might considerably improve the potential of the technique. In addition to displaying sufficiently different resonance frequencies of their mobile protons, it is also important that the CEST agents designed for this application are highly sensitive. LIPOCEST agents represent the most sensitive class of CEST systems developed so far. On this basis, two LIPOCEST samples, a spherical one and an osmotically shrunken nonspherical one, endowed with markedly different resonance frequencies of their intraliposomal water protons, 3 ppm and 15 ppm, respectively, were prepared and tested both in vitro and in ex-vivo on a bovine muscle used as tissue-surrogate. The response of the two agents did not interfere each other, thus allowing the multiple visualization of the two agents present at nanomolar concentrations in the same image voxels.

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confidence: 90%

First ex‐vivo MRI co‐localization of two LIPOCEST agents

Terreno

Castelli

Milone

et al. 2008

Contrast Media & Molecular

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“…CEST MRI has been increasingly applied in disorders such as stroke, tumor, multiple sclerosis, and renal injury, augmenting routine diagnostic imaging (Yoo et al , 2007; Sun et al , 2007b; Sun et al , 2011b; Zhou et al , 2011; Sun et al , 2012; Dula et al , 2012; Liu et al , 2012; Chan et al , 2013; McVicar et al , 2014; Longo et al , 2014; Jia et al , 2011). Whereas continuous wave (CW) radio-frequency (RF) irradiation has been commonly implemented on preclinical scanners, CW irradiation is often not feasible on clinical scanners due to RF duty cycle limitation, and pulse-train RF irradiation scheme has to be utilized in translational CEST imaging.…”

Section: Introductionmentioning

confidence: 99%

Fast simulation and optimization of pulse-train chemical exchange saturation transfer (CEST) imaging

Xiao

Sun

2015

Phys. Med. Biol.

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Chemical exchange saturation transfer (CEST) MRI has been increasingly applied to detect dilute solutes and physicochemical properties, with promising in vivo applications. Whereas CEST imaging has been implemented with continuous wave (CW) radio-frequency (RF) irradiation on preclinical scanners, pulse-train irradiation is often chosen on clinical systems. Therefore, it is necessary to optimize pulse-train CEST imaging, particularly important for translational studies. Because conventional Bloch-McConnell formulas are not in the form of homogeneous differential equations, the routine simulation approach simulates the evolving magnetization step by step, which is time consuming. Herein we developed a computationally efficient numerical solution using matrix iterative analysis of homogeneous Bloch-McConnell equations. The proposed algorithm requires simulation of pulse-train CEST MRI magnetization within one irradiation repeat, with 99% computation time reduction from that of conventional approach under typical experimental conditions. The proposed solution enables determination of labile proton ratio and exchange rate from pulse-train CEST MRI experiment, within 5% from those determined from quantitative CW-CEST MRI. In addition, the structural similarity index analysis shows that the dependence of CEST contrast on saturation pulse flip angle and duration between simulation and experiment was 0.98±0.01, indicating that the proposed simulation algorithm permits fast optimization and quantification of pulse-train CEST MRI.

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“…In this perspective, Yoo et al have recently developed a PARACEST probe that detects caspase-3. [9,10] Here we report the first representative of a new, versatile platform of PARACEST agents designed for specific detection of a wide variety of enzymes. The molecular design is based on coupling an enzyme-specific substrate to a lanthanide-chelating unit through a self-immolative spacer (Scheme 1).…”

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confidence: 99%