A 16-Channel 13C Array Coil for Magnetic Resonance Spectroscopy of the Breast at 7T

• Published in: IEEE transactions on biomedical engineering 2021-06, Vol.68 (6), p.2036-2046
• Main Authors: Wilcox, Matthew, Ogier, Stephen, Cheshkov, Sergey, Dimitrov, Ivan, Malloy, Craig, Wright, Steven, McDougall, Mary
• Format: Article
• Language: English
• Subjects: array coils; Arrays; Biomedical measurement; Breast cancer; Capacitors; carbon-13; Coils; Decoupling; Elevation; Fatty acids; Field of view; Frequency measurement; Gyromagnetic ratio; In vivo methods and tests; Lipids; Localization; Low-pass filters; Magnetic resonance spectroscopy; Metabolites; MRS; multinuclear; Neoplasms; Penetration depth; Preamplifiers; Radio frequency; RF coils; Sensitivity; Signal to noise ratio; Spectroscopic analysis; Spectroscopy; Spectrum analysis
• ISSN: 0018-9294; 1558-2531
• DOI: 10.1109/TBME.2021.3063061

Objective: Considering the reported elevation of ω-6/ω-3 fatty acid ratios in breast neoplasms, one particularly important application of 13 C MRS could be in more fully understanding the breast lipidome's relationship to breast cancer incidence. However, the low natural abundance and gyromagnetic ratio of the 13 C isotope lead to detection sensitivity challenges. Previous 13 C MRS studies have relied on the use of small surface coils with limited field-of-view and shallow penetration depths to achieve adequate signal-to-noise ratio (SNR), and the use of receive array coils is still mostly unexplored. Methods: This work presents a unilateral breast 16-channel 13 C array coil and interfacing hardware designed to retain the surface sensitivity of a single small loop coil while improving penetration depth and extending the field-of-view over the entire breast at 7T. The coil was characterized through bench measurements and phantom 13 C spectroscopy experiments. Results: Bench measurements showed receive coil matching better than -17 dB and average preamplifier decoupling of 16.2 dB with no evident peak splitting. Phantom MRS studies show better than a three-fold increase in average SNR over the entirety of the breast region compared to volume coil reception alone as well as an ability for individual array elements to be used for coarse metabolite localization without the use of single-voxel or spectroscopic imaging methods. Conclusion: Our current study has shown the benefits of the array. Future in vivo lipidomics studies can be pursued. Significance: Development of the 16-channel breast array coil opens possibilities of in vivo lipidomics studies to elucidate the link between breast cancer incidence and lipid metabolics.