A generalized strategy for designing ¹⁹F/¹H dual‐frequency MRI coil for small animal imaging at 4.7 Tesla

Abstract

Purpose:To propose and test a universal strategy for building 19F/1H dual‐frequency RF coil that permits multiple coil geometries.Materials and Methods:The feasibility to design 19F/1H dual‐frequency RF coil based on coupled resonator model was investigated. A series capacitive matching network enables robust impedance matching for both harmonic oscillating modes of the coupled resonator. Two typical designs of 19F/1H volume coils (birdcage and saddle) at 4.7T were implemented and evaluated with electrical bench test and in vivo 19F/1H dual‐nuclei imaging.Results:For various combinations of internal resistances of the sample coil and secondary resonator, numerical solutions for the tunable capacitors to optimize impedance matching were obtained using a root‐seeking program. Identical and homogeneous B1 field distribution at 19F and 1H frequencies were observed in bench test and phantom image. Finally, in vivo mouse imaging confirmed the sensitivity and homogeneity of the 19F/1H dual‐frequency coil design.Conclusion:A generalized strategy for designing 19F/1H dual‐frequency coils based on the coupled resonator approach was developed and validated. A unique feature of this design is that it preserves the B1 field homogeneity of the RF coil at both resonant frequencies. Thus it minimizes the susceptibility effect on image co‐registration. J. Magn. Reson. Imaging 2011;. © 2011 Wiley‐Liss, Inc.

MR cholangiography demonstrates unsuspected rapid biliary clearance of nanoparticles in rodents: Implications for clinical translation

“…In example 2, PFOB NP were injected via tail vein into a 100 g male Harlan rat at 1.0 ml/kg and allowed to circulate for 2 hours prior to imaging. High-resolution 1 H/ 19 F MR images were acquired at 3T (Philips Achieva) using an in-house, custom dual-tuned open birdcage transmit-receive coil 5, 6 . Simultaneous 3D 1 H/ 19 F imaging was used employing a novel steady state ultrashort echo time (UTE) technique (TE/TR=0.1 ms/1.96 ms) with the frequencies set to the resonance of 1 H and the CF 2 groups of the PFOB spectrum (representing 12 of 17 total 19 F nuclei) 7 .…”

19F-MRI for monitoring human NK cellsin vivo

“…14,20,21 Because there are trace amounts of fluorine in the body (mainly in the bone matrix and teeth) that exhibit a very CONTACT Christian M. Capitini ccapitini@pediatrics.wisc.edu short spin-spin relaxation time, 15 there is minimal background "noise" and infusions of 19 F-labeled cells could be easily identified at a high contrast to noise ratio. 22 With a high gyromagnetic ratio similar to that of 1 H, 19 F has favorable physical properties that improve inherent receptivity and sensitivity, requiring only millimolar quantities per voxel for detection. 22 Furthermore, 19 F is non-radioactive, non-invasive; depth independent since used by MRI and has no known enzyme for its degradation in vivo (cleared by exhalation or by endoreticulum).…”

“…22 With a high gyromagnetic ratio similar to that of 1 H, 19 F has favorable physical properties that improve inherent receptivity and sensitivity, requiring only millimolar quantities per voxel for detection. 22 Furthermore, 19 F is non-radioactive, non-invasive; depth independent since used by MRI and has no known enzyme for its degradation in vivo (cleared by exhalation or by endoreticulum). Moreover, perfluorocarbon liquids are chemically and biologically inert, and no toxicity has ever been reported using 19 F-labeled cells, 23 even at large doses.…”

Electromagnetic Field and Radio Frequency Circuit Co-Simulation for Magnetic Resonance Imaging Dual-Tuned Radio Frequency Coils

“…3(b). A dual-tuned circuit was added to achieve the resonant frequency 115.9 MHz for fluorine ( 19 F) and 123.2 MHz for hydrogen ( 1 H) at 3 T [14]. The dual-tuned circuit structure is depicted in Fig.…”