mrm29145-sup-0001-Supinfo.docxWord 2007 document , 2.1 MB

FIGURE S1 Compact, cryogen-free PET/MR scanner system utilized for HP [1-13C]MRI/FDG-PET imaging experiments

FIGURE S2 Three-axis background magnetic field recordings along the transfer path, captured using a smartphone-embedded Hall effect sensor array, translated along the transfer path at an approximately constant speed (Hardware: iPhone XR, Apple; Software: phyphox, Aachen University). Individual components are determined in the probe’s frame of reference. Zero-crossing was detected near the midpoint of the path, which bisects opposing 3-T human scanner installations, with three other high-field preclinical MRI magnets also situated nearby, in addition to the system used for the present study

FIGURE S3 Simulated evolutions of 13C pyruvate (blue lines) and lactate (red lines) magnetization during HP MRSI experiments with varying flip angle schemes (A–D). Longitudinal magnetization is shown in top rows and MR signal is shown in bottom rows. Schemes (B & D) were actually utilized in this study. Integrated lactate signal is 38% higher for scheme (D) vs scheme (B), demonstrating how multi-band excitation can outperform broadband excitation for the purpose of improved lactate detection. The multi-band scheme affords larger lactate MR signals by preserving the magnetization of the injected pyruvate for subsequent metabolic conversion to lactate. The computed magnetization dynamics were calculated in MATLAB from the convolution of a gamma-variate input function (α = 3.3, β = 4.0, t0 = 2 s) with a decaying exponential residue function to model tissue kinetics, with the magnetization subjected to: (A) repeated excitation pulses according to the corresponding flip angle scheme (starting at t = 20 s, with TR = 250 ms), (B) T1 relaxation (T1,pyruvate = 30 s, T1,lactate = 20 s), and (C) a constant rate of unidirectional conversion of pyruvate to lactate magnetization (kPL = 0.02 s−1)

FIGURE S4 Vendor-supplied data on RF amplifier output as a function of input power and frequency. Performance has been characterized at 40, 70, 100, and 120 MHz. The relevant range of input power (Pin) is <10 dBm. The same amplifier was used for both 13C and 1H scans. Linearity of output is good across the frequency range, suggesting that there should be minimal impact of measuring the 13C SSRF profiles at the 1H frequency