TY - JOUR
T1 - Multispectral MRI with dual fluorinated probes to track mononuclear cell activity in mice
AU - Chirizzi, Cristina
AU - De Battista, Davide
AU - Tirotta, Ilaria
AU - Metrangolo, Pierangelo
AU - Comi, Giancarlo
AU - Bombelli, Francesca Baldelli
AU - Chaabane, Linda
PY - 2019/5
Y1 - 2019/5
N2 - Background: MRI with fluorine 19 (19F) probes has shown an ability to track immune cell activity with a specific, stable, and quantitative signal. In addition, the chemical shift differences of selected 19F probes make dual-probe imaging possible. To improve 19F MRI sensitivity for dual-probe imaging, optimal fluorine probes are needed. Purpose: To develop multispectral 19F MRI to image immune cell activity in vivo using 19F nanoparticles of two distinct fluorocarbons. Materials and Methods: Both 19F nanoparticles formulated with two fluorocarbons with distinct resonance frequencies and a high fluorine payload were characterized in terms of size, stability, MR profile, and relaxation times at 7 T. 19F MRI sensitivity was tested on labeling cells both in vitro and in vivo in C57BL/6 mice after conditional ablation of myeloid cells through the inhibition of colony-stimulating factor-1 receptor (CSF1Ri) to monitor the change of immune cells phagocytosis. Fluorine MRI data were acquired at the resonance frequency of each fluorocarbon by using a three-dimensional fast spin-echo sequence. Fluorescent dyes were also inserted into 19F nanoparticles to allow flow-cytometric and confocal microscopy analysis of labeled cells. Fluorine signal-tonoise ratio (SNR) was compared by using two-way repeated measures analysis of variance with Bonferroni post hoc correction. Results: Fluorine MRI demonstrated high sensitivity and high specificity in the imaging of mononuclear cells both in vitro and in vivo. In combination with proton MRI, a map of 19F nuclei from each fluorocarbon was obtained without overlaps or artifacts. In vitro cell viability was unchanged, and 8000 cells with a high SNR (.8) were detected. In vivo high fluorine signal was observed in the bone marrow (SNR . 15) immediately after CSF1Ri treatment interruption, which correlated with high uptake by neutrophils and monocytes at flow cytometry. Conclusion: By assessing in vivo MRI of mononuclear cell phagocytic ability with 19F nanoparticles, MRI with dual 19F probes can effectively track immune cell activity in combination with current MRI protocols.
AB - Background: MRI with fluorine 19 (19F) probes has shown an ability to track immune cell activity with a specific, stable, and quantitative signal. In addition, the chemical shift differences of selected 19F probes make dual-probe imaging possible. To improve 19F MRI sensitivity for dual-probe imaging, optimal fluorine probes are needed. Purpose: To develop multispectral 19F MRI to image immune cell activity in vivo using 19F nanoparticles of two distinct fluorocarbons. Materials and Methods: Both 19F nanoparticles formulated with two fluorocarbons with distinct resonance frequencies and a high fluorine payload were characterized in terms of size, stability, MR profile, and relaxation times at 7 T. 19F MRI sensitivity was tested on labeling cells both in vitro and in vivo in C57BL/6 mice after conditional ablation of myeloid cells through the inhibition of colony-stimulating factor-1 receptor (CSF1Ri) to monitor the change of immune cells phagocytosis. Fluorine MRI data were acquired at the resonance frequency of each fluorocarbon by using a three-dimensional fast spin-echo sequence. Fluorescent dyes were also inserted into 19F nanoparticles to allow flow-cytometric and confocal microscopy analysis of labeled cells. Fluorine signal-tonoise ratio (SNR) was compared by using two-way repeated measures analysis of variance with Bonferroni post hoc correction. Results: Fluorine MRI demonstrated high sensitivity and high specificity in the imaging of mononuclear cells both in vitro and in vivo. In combination with proton MRI, a map of 19F nuclei from each fluorocarbon was obtained without overlaps or artifacts. In vitro cell viability was unchanged, and 8000 cells with a high SNR (.8) were detected. In vivo high fluorine signal was observed in the bone marrow (SNR . 15) immediately after CSF1Ri treatment interruption, which correlated with high uptake by neutrophils and monocytes at flow cytometry. Conclusion: By assessing in vivo MRI of mononuclear cell phagocytic ability with 19F nanoparticles, MRI with dual 19F probes can effectively track immune cell activity in combination with current MRI protocols.
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U2 - 10.1148/radiol.2019181073
DO - 10.1148/radiol.2019181073
M3 - Article
C2 - 30888930
AN - SCOPUS:85065050765
VL - 291
SP - 351
EP - 357
JO - Radiology
JF - Radiology
SN - 0033-8419
IS - 2
ER -