Clinical Perspectives of Hybrid Proton-Fluorine Magnetic Resonance Imaging and Spectroscopy

Abstract

The number of applications of fluorine 19 (19F) magnetic resonance (MR) imaging and spectroscopy in biomedical and clinical research is steadily growing. The 100% natural abundance of fluorine and its relatively high sensitivity for MR (83% to that of protons) make it an interesting nucleus for a wide range of MR applications. Fluorinated contrast media have a number of advantages over the conventionally used gadolinium-based or iron-based contrast agents. The absence of an endogenous fluorine background intensity in the human body facilitates reliable quantification of fluorinated contrast medium or drugs. Anatomy can be visualized separately with proton MR imaging, creating the application of hybrid hydrogen 1 (1H)/19F MR imaging. The availability of 2 channels (ie, the 1H and 19F channels) enables dual-targeted molecular imaging. Recently, novel developments have emerged on fluorine-based contrast media in preclinical studies and imaging techniques. The developments in fluorine MR seem promising for clinical applications, with contributions in therapy monitoring, assessment of lung function, angiography, and molecular imaging. This review outlines the translation from recent advances in preclinical MR imaging and spectroscopy to future perspectives of clinical hybrid 1H/19/F MR imaging applications.

Noninvasive Imaging of Early Venous Thrombosis by 19 F Magnetic Resonance Imaging With Targeted Perfluorocarbon Nanoemulsions

“…Furthermore, perfluorocarbons are biochemically inert as a result of the strong C-F bond, which cannot be cleaved by enzymes, and are therefore nontoxic. 49 Human application of SPIT is feasible with the use of the clinically relevant perfluorooctyl bromide and perfluorodecalin emulsions, which are characterized by short biological half-lives 34 and have been used in human trials. Because of the excellent sensitivity and specificity, we propose that α2 AP -PFCs, in conjunction with 19 F MRI, are a suitable future option for the detection of small thrombi even with a clinical MR scanner at 3 T.…”

Novel 19F Activatable Probe for the Detection of Matrix Metalloprotease-2 Activity by MRI/MRS

“…36,41 Our activatable probe encountered similar issue since millimolar concentration was required to provide enough 19 F signal to visualize MMP activity. Further advances in both instrumentation and chemistry, such as increasing the number of equivalent fluorine in the probe design for higher sensitivity, 26 are required to improve the detection limit.…”

Fluorinated MRI Contrast Agents and Their Versatile Applications in the Biomedical Field

“…19 F is the only natural stable fluorine isotope and its NMR sensitivity is of 83.4 % compared to the proton sensitivity. Its gyromagnetic ratio of 40.08 MHzT -1 is slightly lower than that of 1 H. Fluorine has 7 outer-shell electrons leading to strong chemical shift effects [47]. Compared to the 1 H nucleus, fluorine MRI signal-to-noise ratio (SNR) is of about 89 % which makes it a good alternative to proton MRI.…”

“…Physiological concentrations of fluorine atoms are below the detection limit of magnetic resonance technique. Moreover, fluorine is also present at higher concentrations in bones and teeth but in solid 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 [47].…”