title: (19)F MRSI of capecitabine in the liver at 7 T using broadband transmit-receive antennas and dual-band RF pulses.
abstract: Capecitabine (Cap) is an often prescribed chemotherapeutic agent, successfully used to cure some patients from cancer or reduce tumor burden for palliative care. However, the efficacy of the drug is limited, it is not known in advance who will respond to the drug and it can come with severe toxicity. (19)F Magnetic Resonance Spectroscopy (MRS) and Magnetic Resonance Spectroscopic Imaging (MRSI) have been used to non-invasively study Cap metabolism in vivo to find a marker for personalized treatment. In vivo detection, however, is hampered by low concentrations and the use of radiofrequency (RF) surface coils limiting spatial coverage. In this work, the use of a 7T MR system with radiative multi-channel transmit-receive antennas was investigated with the aim of maximizing the sensitivity and spatial coverage of (19)F detection protocols. The antennas were broadband optimized to facilitate both the (1)H (298 MHz) and (19)F (280 MHz) frequencies for accurate shimming, imaging and signal combination. B1(+) simulations, phantom and noise measurements showed that more than 90% of the theoretical maximum sensitivity could be obtained when using B1(+) and B1(-) information provided at the (1)H frequency for the optimization of B1(+) and B1(-) at the (19)F frequency. Furthermore, to overcome the limits in maximum available RF power, whilst ensuring simultaneous excitation of all detectable conversion products of Cap, a dual-band RF pulse was designed and evaluated. Finally, (19)F MRS(I) measurements were performed to detect (19)F metabolites in vitro and in vivo. In two patients, at 10 h (patient 1) and 1 h (patient 2) after Cap intake, (19)F metabolites were detected in the liver and the surrounding organs, illustrating the potential of the set-up for in vivo detection of metabolic rates and drug distribution in the body.
authors.affiliation: University Medical Center Utrecht, Image Sciences Institute, Utrecht, the Netherlands.
authors.forename: Jetse S
authors.initials: JS
authors.lastname: van Gorp
authors.affiliation: University Medical Center Utrecht, Image Sciences Institute, Utrecht, the Netherlands.
authors.forename: Peter R
authors.initials: PR
authors.lastname: Seevinck
authors.affiliation: University Medical Center Utrecht, Radiotherapy, Utrecht, the Netherlands.
authors.forename: Anna
authors.initials: A
authors.lastname: Andreychenko
authors.affiliation: University Medical Center Utrecht, Radiology, Utrecht, the Netherlands.
authors.forename: Alexander J E
authors.initials: AJ
authors.lastname: Raaijmakers
authors.affiliation: University Medical Center Utrecht, Radiology, Utrecht, the Netherlands.
authors.forename: Peter R
authors.initials: PR
authors.lastname: Luijten
authors.affiliation: University Medical Center Utrecht, Image Sciences Institute, Utrecht, the Netherlands.
authors.forename: Max A
authors.initials: MA
authors.lastname: Viergever
authors.affiliation: University Medical Center Utrecht, Medical Oncology, Utrecht, the Netherlands.
authors.forename: Miriam
authors.initials: M
authors.lastname: Koopman
authors.affiliation: Hvidovre Hospital, Danish Research Center for Magnetic Resonance, Hvidovre, Denmark.
authors.forename: Vincent O
authors.identifier: http://orcid.org/0000-0001-6026-3134
authors.initials: VO
authors.lastname: Boer
authors.affiliation: University Medical Center Utrecht, Radiology, Utrecht, the Netherlands.
authors.forename: Dennis W J
authors.initials: DW
authors.lastname: Klomp
mesh_terms: D000964:Antimetabolites, Antineoplastic / Q000378:metabolism; D000069287:Capecitabine / Q000378:metabolism*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005461:Fluorine / Q000493:pharmacokinetics; D066235:Fluorine-19 Magnetic Resonance Imaging / Q000379:methods*; D006801:Humans; D008099:Liver / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy / Q000295:instrumentation*; D019047:Phantoms, Imaging; D011846:Radio Waves; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*; D014018:Tissue Distribution; D014159:Transducers
chemical_list: D000964:Antimetabolites, Antineoplastic; D019275:Radiopharmaceuticals; D005461:Fluorine; D000069287:Capecitabine
keywords: 19 F MRSI; X-nuclei; broadband transmit-receive antennas; cancer therapy response; capecitabine; dual-frequency pulses; high field