(19)F MRSI of capecitabine in the liver at 7 T using broadband transmit-receive antennas and dual-band RF pulses.
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.
['van Gorp|Jetse S|JS|', 'Seevinck|Peter R|PR|', 'Andreychenko|Anna|A|', 'Raaijmakers|Alexander J E|AJ|', 'Luijten|Peter R|PR|', 'Viergever|Max A|MA|', 'Koopman|Miriam|M|', 'Boer|Vincent O|VO|http://orcid.org/0000-0001-6026-3134', 'Klomp|Dennis W J|DW|']
D000964:Antimetabolites, Antineoplastic D000069287:Capecitabine D004867:Equipment Design D019544:Equipment Failure Analysis D005461:Fluorine D066235:Fluorine-19 Magnetic Resonance Imaging D006801:Humans D008099:Liver D009682:Magnetic Resonance Spectroscopy D019047:Phantoms, Imaging D011846:Radio Waves D019275:Radiopharmaceuticals D015203:Reproducibility of Results D012680:Sensitivity and Specificity D012815:Signal Processing, Computer-Assisted D014018:Tissue Distribution D014159:Transducers
capecitabine broadband transmit-receive antennas 19 F MRSI X-nuclei cancer therapy response dual-frequency pulses high field