Optimized multiple-quantum filter for robust selective excitation of metabolite signals.
The selective excitation of metabolite signals in vivo requires the use of specially adapted pulse techniques, in particular when the signals are weak and the resonances overlap with those of unwanted molecules. Several pulse sequences have been proposed for this spectral editing task. However, their performance is strongly degraded by unavoidable experimental imperfections. Here, we show that optimal control theory can be used to generate pulses and sequences that perform almost ideally over a range of rf field strengths and frequency offsets that can be chosen according to the specifics of the spectrometer or scanner being used. We demonstrate this scheme by applying it to lactate editing. In addition to the robust excitation, we also have designed the pulses to minimize the signal of unwanted molecular species.
Experimental Physics III, TU Dortmund University, 44227 Dortmund, Germany. Electronic address: mirjam.holbach@tu-dortmund.de.
Mirjam
M
Holbach
Leibniz-Institut für Analytische Wissenschaften, ISAS e.V., 44139 Dortmund, Germany.
Jörg
J
Lambert
Experimental Physics III, TU Dortmund University, 44227 Dortmund, Germany.
Dieter
D
Suter
D000409:Alanine / Q000032:analysis*; D000465:Algorithms; D019344:Lactic Acid / Q000032:analysis*; D008055:Lipids / Q000032:analysis*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted
D008055:Lipids; D019344:Lactic Acid; D000409:Alanine
Lactate editing; MRS; Optimal control; Robust pulses; SSel-MQC