Luiz Celso Hygino Da Cruz MD, Presenter: Nothing to Disclose

Fabiana B Ferreira MD, Abstract Co-Author: Nothing to Disclose

Rachel E Maia MD, Abstract Co-Author: Nothing to Disclose

Roberto Cortes Domingues MD, Abstract Co-Author: Nothing to Disclose

Andre Barbosa MD, Abstract Co-Author: Nothing to Disclose

Romeu Cortes Domingues MD, Abstract Co-Author: Nothing to Disclose

To determine whether DTi can demonstrate micro-structural changes in the normal appearing white matter (NAWM) surrounding multiple sclerosis (MS) plaques. To confirm the ability of DTi in the detection of white matter abnormalities. To confirm whether there is difference in DTi anisotropy in acute and chronic MS plaques and in the NAWM.

MR standard protocol and DTi were performed in 35consecutive patients (12men, 23women; mean age32.6y) and 27 healthy volunteers (9men, 18women; mean age29.5y). DTi was performed using a diffusion-weighted echo-planar imaging applied in six different gradients directions. Fractional anisotropy (FA) was obtained from DTi data as an index of anisotropy. A single observed placed uniform regions of interest (ROIs) with the same size on plaques, periplaques and NAWM regions. Identical ROIs were also drawn in the corresponding location in the age-matched control subjects. The same observer compared the size of the plaques on the FA maps with its size on the T2Wi and recorded them as being larger or smaller.

The mean FA value measured in MS plaque was 0.259, in periplaque white matter (PWM) regions was 0.345, in the NAWM adjacent to the PWM(aNAWM) 0.508, in the contra lateral NAWM(clNAWM) 0.589 and in the control subjects white matter(cWM) 0.587. Significant difference was found between plaque FA values and the PWM as well as with the others regions. There was also a significant difference between the PWM and the aNAWM, clNAWM and the cWM. No significant difference was verified between the aNAWM, the clNAWM and the cWM. Mean FA values of acute plaque(0.137) were lower than the FA values of the chronic plaques(0.276). The ROI size of the plaque measured in the T2Wi were smaller than the size of the plaque measured in the FA maps.

DTi support the hypothesis that extension of the white matter disease is an outward direction from the plaque. This is confirmed by the fact that the FA values are reduced in the periplaque white matter when compared to normal controls. Alterations in the plaque anisotropy can also be helpful in the distinguishing of acute and chronic plaques. DTi may be the most accurate method to assess MS.

Da Cruz, L, Ferreira, F, Maia, R, Domingues, R, Barbosa, A, Domingues, R, Diffusion Tensor MR Imaging (DTi) Assessment of Multiple Sclerosis Plaques and Normal Appearing White Matter.  Radiological Society of North America 2004 Scientific Assembly and Annual Meeting, November 28 - December 3, 2004 ,Chicago IL. http://archive.rsna.org/2004/4411204.html