N-AcetylLaspartic Acid Phantom for Proton Magnetic Resonance Spectroscopy at 1.5 T and 3 T

Abstract

Proton Magnetic Resonance Spectroscopy (MRS) phantoms are an important tool for quality assurance and reliability. Some of the contents are not easily available in some countries due to some company policies. We built a phantom using N-Acetyl-DL-aspartic acid as a substitute for N-Acetyl-L-aspartic acid for proton magnetic resonance spectroscopy of human brain at 1.5 T and 3 T. To quantify the B0 homogeneity, phase and magnitude images of a commercial phantom were also acquired with a standard gradient echo sequence. Spectra obtained were corrected and dismissed critical chemical shift due to inhomogeneities. Spectra numerical simulations at 1.5 T and 3 T were performed using a free jMRUI and point resolved spectroscopy sequence for various times of echo. In vitro single-voxel spectra were obtained with the phantom prototype and a commercial phantom using the substitute acid and the same pulse sequence and magnetic field magnitudes as before. Simulated and in vitro spectra showed a very good concordance and majority of metabolites were readily identified for both fields. Spectra acquired with the phantom prototype complied with those quality control criteria for clinical use for both field strengths. This approach offers an alternative way to conduct clinical magnetic resonance spectroscopy.