FAST 3D PEDIATRIC BRAIN MRSI

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Introduction: Pediatric neurospectroscopy provides unique information regarding the metabolic variations during normal and abnormal brain development. Spectroscopic imaging can add to this feature by providing topologic information, but rapid scan times are needed for clinical feasible protocols. We have thus developed a 6 min 3D MRSI clinical protocol to study. The clinical goal is to understand the metabolic differences in subjects with motor dysfunction by analyzing metabolite levels in the corticospinal tract (CST). Methods and Discussion: A 3D MRSI sequence was developed using PRESS excitation in combination with a spiral based readout gradient for use at 3T. A dualband spectral spatial spin echo pulse for 3T neuro applications, designed to excite only 1% of the water signal and suppress lipids while passing the NAA, Cr, and Cho resonances was used. Data collection using a 8 channel receiver coil provided increased signal to noise ratio (SNR). Overall, the following MRSI parameters were used for data collection; 3T, TR/TE = 1500/130 ms, 32x32x8 matrix, 1cc spatial resolution, 6:24 min scan time. Quantification was performed by measuring voxels corresponding to the CST and incoporating this into the LCModel fitting procedure. In vivo studies demonstrated excellent results with SNRs exceeding that from adults. Metabolite values were recorded from the CST beginning at the precentral gyrus lateral to the centrum semiovale and ending at the cerebral peduncle region. NAA/Cho showed a linear trend in the change of metabolite ratios for the CST given this age range. Further data collection is needed to confirm this trend. Regardless, the ability to analyze spectra from the whole CST pathway (and other pathways) is unique using spectroscopic imaging. Acknowledgements: NIH RR 09784, NS40117, NS46432, RR01271