UIC-2013-092 – Methods for Reducing Chemical Shift Displacement Errors in 2D MR Spectroscopy (J-LASER and J-sLASER)

Magnetic Resonance (MR) spectroscopy is a non-invasive diagnostic test that measures biochemical changes in the brain to differentiate between different neurological conditions and tumor types. Current spectroscopic techniques for acquiring an MR spectroscopy scan, such as conventional two-dimensional (2D) J-resolved spectroscopy with voxel localization by PRESS, called “J-PRESS”, suffers from significant limitations. Such limitations include large chemical shift displacement errors, additional J-refocused artifactual peaks from spatially dependent J-coupling evolution, and sensitivity to radiofrequency (RF) field inhomogeneity. These limitations are more evident at relatively higher magnetic field strengths such as 3 Tesla and 7 Tesla. UIC inventors have created two new 2D J-resolved fully- and semi-localized by adiabatic selective refocusing (LASER and semi-LASER) spectroscopy, called “J-resolved LASER” or “J-LASER” and “J-resolved sLASER” or “J-sLASER” to address the above limitations of J-PRESS. Three pairs of adiabatic full-passage (AFP) pulses are employed for voxel localization in J-resolved LASER or J-LASER and two pairs in J-resolved sLASER or J-sLASER, respectively. More critically, the first half of t1 period was inserted between the last pair of AFP pulses to encode the second dimension to obtain 2D adiabatic J-resolved spectroscopy. Phantom and human experiments have successfully demonstrated the feasibility of these new methods and their advantages over conventional J-PRESS. Hyunjin Kim hkim227@otm.uic.edu 312355-7843