Andreas Stadlbauer MS, Presenter: Nothing to Disclose

Stephan Gruber MD, Abstract Co-Author: Nothing to Disclose

Csilla Balassy MD, Abstract Co-Author: Nothing to Disclose

Katja Pinker MD, Abstract Co-Author: Nothing to Disclose

Ewald Moser PhD, Abstract Co-Author: Nothing to Disclose

The aim of this preliminary study was the evaluation of metabolic changes in patients with previously diagnosed multiple sclerosis by repeated standard MR imaging and high-field MRSI-experiments. Special interest was the detection of metabolic changes before the patients showed clinical symptoms of an active MS episode.

All 3D 1H-MRSI experiments were performed on a 3T MR scanner equipped with a birdcage head coil. A hybrid-sequence consisting of a 2D-CSI and 1D-Hadamard-encoding, TR=1600ms and TE=135ms was used. Standard MR images (T2w; T1w contrast-enhanced) were acquired using a 1.5T MR scanner 2 days before the MRSI-experiment. Four patients (mean age 35 years) were examined three times over a time period of 4 month. Metabolic maps of Cho/NAA were computed and the metabolic changes of Cho/tNAA, Cho/Cr, tNAA/Cr were calculated using LCModel. Correlation tests for lesion-load in T2w MRIs and metabolic changes were performed. Contrast enhanced T1w MRIs were correlated with the metabolic changes visible in the previous session.

A total of 110 areas of metabolic changes were found in the metabolic maps whereas standard T2w MRIs demonstrated 109 hyperintense lesions. Location of the MRSI visible lesion correlated in 43% with the lesion on standard MRI, 57% were found only in MRSI. The matching lesions showed decreased tNAA and increased Cho, whereas the lesions which only were visible in metabolic maps showed only decreased tNAA. Lesion load showed positive correlation with the quantified changes of Cho/Cr (r=0.770 to 0.997) and Cho/NAA (r=0.725 to 0.839), and negative with NAA/Cr (r=-0.468 to -0.637). In one case eight weeks before an MS episode metabolic changes were visible whereas T1w MRIs demonstrated no changes. During the episode MRI revealed a contrast enhancing lesion that correlated well with the previously detected metabolic changes.

1H-MRSI at 3T seem to be a promising tool for the evaluation of metabolic changes in patients with multiple sclerosis. The evaluation of metabolic changes prior to T1w contrast enhancing respectively active plaques visible during active episodes may be helpful in therapy planning and patient follow-up.

Stadlbauer, A, Gruber, S, Balassy, C, Pinker, K, Moser, E, Three-dimensional 1H-MRSI in Patients with Multiple Sclerosis at 3 Tesla: A Time-resolved Study.  Radiological Society of North America 2004 Scientific Assembly and Annual Meeting, November 28 - December 3, 2004 ,Chicago IL. http://archive.rsna.org/2004/4410803.html