Christine Grace Nunweiler MD, Presenter: Nothing to Disclose

Anthony Traboulsee MD, Abstract Co-Author: Nothing to Disclose

Matthew Lam, Abstract Co-Author: Nothing to Disclose

Erin MacMillan, Abstract Co-Author: Nothing to Disclose

Alex L MacKay PhD, Abstract Co-Author: Nothing to Disclose

Trudy Harris, Abstract Co-Author: Nothing to Disclose

David Kwok Boon Li MD, Abstract Co-Author: Nothing to Disclose

et al, Abstract Co-Author: Nothing to Disclose

Gadolinium (gad) enhancing lesions represent breakdown in the blood brain barrier and indicate active inflammation in multiple sclerosis (MS). Decreased N-acetylaspartate (NAA) content in MS lesions and normal appearing white matter (NAWM) correlates pathologically with a greater loss of axons and/or axonal dysfunction. The goal was to determine if the NAA/creatine (NAA/Cr) ratio of NAWM for multiple sclerosis patients with gad enhancing lesions differed from that for patients without gad enhancing lesions.

22 patients with clinically definite multiple sclerosis with at least one clinical relapse in the past year, and not currently on disease modifying therapy were recruited for possible entry into a clinical trial (Teva 9014). A brain MRI with gad was performed on a Philips 3T scanner. Magnetic resonance spectroscopy was performed on all patients screened using a single box-like voxel centered over the corpus callosum. Following local shimming on the selected voxel to optimize magnetic field homogeneity, proton spectra were acquired using a Point Resolved Spectroscopy (PRESS) sequence (TR 5000ms/TE 144ms with 32 acquisitions) and water suppression using a 3 pulse CHESS sequence. Spectra were analyzed using the LCModel by a single evaluator blinded to the presence or absence of gad enhancing lesions. The NAA/Cr, choline/ creatine (Cho/Cr), and myoinositol/ creatine (MI/Cr) ratios for those MS patients who had, or did not have, gad enhancing lesions were compared using a students t-test for significance at a p value of <0.05.

7 patients had at least one gad enhancing lesion, while 15 patients did not have any enhancing lesions. Mean NAA/Cr were 1.947 (±0.469) versus 1.912 (±0.175), mean Cho/Cr 0.365 (±0.102) versus 0.347 (±0.047), and mean MI/Cr 0.879 (±0.492) versus 0.843 (±0.544) for the gad enhancing group and non-enhancing group, repectively. There was no significant difference between the two groups.

The degree of NAWM abnormality is similar in MS patients with and without gadolinium enhancing lesions. This suggests that diffuse tissue destruction may be independent of focal lesion activity.

A.T.,D.K.L.: Drs. Li and Traboulsee are members of the UBC MS/MRI Research Group who have been contracted to provide central analysis of the MRI scans for Teva Neurosciences.

Nunweiler, C, Traboulsee, A, Lam, M, MacMillan, E, MacKay, A, Harris, T, Li, D, et al, , 3T High Field Single Voxel Magnetic Resonance Spectroscopy of Normal Appearing White Matter in Multiple Sclerosis Patients with and without Gadolinium Enhancing Lesions.  Radiological Society of North America 2005 Scientific Assembly and Annual Meeting, November 27 - December 2, 2005 ,Chicago IL. http://archive.rsna.org/2005/4418225.html