Comparison of Proton T1 and T2 Relaxation Times of Cerebral Metabolites between 1.5T and 3.0T MRI using a Phantom

Kim, Ji hoon; Chang, Kee Hyun; Song, In Chan

Abstract

PURPOSE: To present the T1 and T2 relaxation times of the major cerebral metabolites at 1.5T and 3.0T and compare those between 1.5T and 3.0T.
MATERIALS AND METHODS
Using the phantom containing N-acetyl aspartate (NAA), Choline (Cho), and Creatine (Cr) at both 1.5T and 3.0T MRI, the T1 relaxation times were calculated from the spectral data obtained with 5000 ms repetition time (TR), 20 ms echo time (TE), and 11 different mixing time (TM)s using STEAM (STimulated Echo-Acquisition Mode) method. The T2 relaxation times were obtained from the spectral data obtained with 3000 ms TR and 5 different TEs using PRESS (Point-RESolved Spectroscopy) method. The T1 and T2 relaxation times obtained at 1.5T were compared with those of 3.0T.
RESULTS
The T1 relaxation times of NAA were 2293 +/- 48 ms at 1.5T and 2559 +/- 124 ms at 3.0T (11.6% increase at 3.0T). The T1 relaxation times of Cho were 2540 +/- 57 ms at 1.5T and 2644 +/- 76 ms at 3.0T (4.1% increase at 3.0T). The T1 relaxation times of Cr were 2543 +/- 75 ms at 1.5T and 2665 +/- 94 ms at 3.0T (4.8% increase). The T2 relaxation times of NAA were 526 +/- 81 ms at 1.5T and 468 +/- 74 ms at 3.0T (11.0% decrease at 3.0T). The T2 relaxation times of Cho were 220 +/- 44ms at 1.5T and 182 +/- 35 ms at 3.0T (17.3% decrease at 3.0T). The T2 relaxation times of Cr were 289 +/- 47 ms at 1.5T and 275 +/- 57 ms at 3.0T (4.8% decrease at 3.0T).
CONCLUSION
The T1 relaxation times of the major cerebral metabolites (NAA, Cr, Cho), which were measured at the phantom, were 4.1%-11.6% longer at 3.0T than at 1.5T. The T2 relaxation times of them were 4.8%-17.3% shorter at 3.0T than at 1.5T. To optimize MR spectroscopy at 3.0T, TR should be lengthened and TE should be shortened.