Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA.
Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, TX, USA.
J Magn Reson. 2022 Oct;343:107286. doi: 10.1016/j.jmr.2022.107286. Epub 2022 Aug 30.
We constructed a C/P surface coil at 3 T for studying cancer metabolism and bioenergetics. In a single scan session, hyperpolarized C-pyruvate MRS and P MRS was carried out for a healthy rat brain.
All experiments were carried out at 3 Tesla. The multinuclear surface coil was designed as two coplanar loops each tuned to either the C or P operating frequency with an LCC trap on the C loop. A commercial volume proton coil was used for anatomical localization and B shimming. Single tuned coils operating at either the C or P frequency were built to evaluate the relative performance of the multinuclear coil. Coil performance metrics consisted of measuring Q factor ratio, calculating system input power using a single-pulse acquisition, and acquiring SNR and flip angle maps using 2D CSI sequences. To observe in vivo spectra, a bolus of hyperpolarized [1-C] pyruvate was administered via tail vein. In vivoC and endogenous P spectra were obtained in a single scan session using 1D slice selective acquisitions.
When compared with single tuned surface coils, the multinuclear coil performance showed a decrease in Q factor ratio, SNR, and transmit efficiency. Flip angle maps showed adequate flip angles within the phantom when the transmit voltage was set using an external phantom. Results show good detection of C labeled lactate, alanine, and bicarbonate in addition to ATP from P MRS.
The coil enables obtaining complementary information within a scan session, thus reducing the number of trials and minimizing biological variability for studies of metabolism and bioenergetics.
我们在 3T 下构建了 C/P 表面线圈，用于研究癌症代谢和生物能量学。在单次扫描过程中，对健康大鼠大脑进行了超极化 C-丙酮酸 MRS 和 P MRS 检测。
所有实验均在 3T 下进行。多核表面线圈设计为两个共面环，每个环调谐到 C 或 P 工作频率，并在 C 环上带有 LCC 陷阱。使用商业容积质子线圈进行解剖定位和 B 匀场。构建了工作在 C 或 P 频率的单调谐线圈，以评估多核线圈的相对性能。线圈性能指标包括测量 Q 因子比、使用单脉冲采集计算系统输入功率，以及使用 2D CSI 序列获取 SNR 和翻转角图。为了观察体内光谱，通过尾静脉给予超极化 [1-C] 丙酮酸。在单次扫描过程中，使用 1D 切片选择性采集获得了体内 C 和内源性 P 谱。
与单调谐表面线圈相比，多核线圈的性能表现出 Q 因子比、SNR 和传输效率降低。当使用外部体模设置传输电压时，翻转角图显示体模内的翻转角足够大。结果显示，除了 P MRS 中的 ATP 外，还能很好地检测到 C 标记的乳酸、丙氨酸和碳酸氢盐。
该线圈能够在单次扫描过程中获得互补信息，从而减少试验次数，最大限度地减少代谢和生物能量学研究中的生物学变异性。
