Diffusion tensor magnetic resonance imaging as molecular diagnostic tool for leukoaraiosis

• Published in: Asian Pacific journal of tropical disease Vol. 4; no. 3; p. 228
• Main Authors: MohdTaib, N.H., Abdullah, A.K. Wan, Shuaib, I.L., Magosso, E., Mat, Isa S.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-06-2014
• ISSN: 2222-1808; 2222-1808
• DOI: 10.1016/S2222-1808(14)60520-X

Diffusion Tensor Imaging (DTI) is a magnetic resonance imaging (MRI) technique that measures mobility of water in biological tissues at molecular level. Useful quantitative parameters offered by DTI include mean diffusivity (MD) which indicates the diffusivity of water molecules in tissues, as well as fractional anisotropy (FA) which quantifies the degree of anisotropy in that particular region. DTI also allows for reconstruction of cerebral nerve fibre tracts through method called fibre tractography. Leukoaraiosis is a brain white-matter change detected as hyperintensity area on T2-weighted image of MRI. It is associated with age and various vascular risk factors, e.g. hypertension and diabetes mellitus. Its aetiology is thought to be related to ischaemia. DTI is expected to provide useful information for characterisation of leukoaraiosis.
To compare MD and FA values as well as fibre tractography between healthy and leukoaraiosis areas in the brain white-matter.
Twelve volunteers with leukoaraiosis (5 male, 7 female; age: 57.0 ± 7.3) underwent brain scan using 1.5T MRI. Only two of them had hypertension, while none had diabetes. MD and FA values were measured for normal and leukoaraiosis areas in three different brain regions, namely the frontal, occipital, and parietal lobes. Fibre tractography was also performed. Comparison of obtained data for leukoaraiosis areas and healthy tissue in the corresponding lobe were performed. p<0.05 was considered statistically significant.
Significantly higher MD and reduced FA were observed in leukoaraiosis area compared to normal tissues in all lobes. Fibre tractography exhibits an obvious discontinuity of several nerve fibre tracts at the area of leukoaraiosis.
Relatively higher MD and reduced FA values seem to distinguish leukoaraiosis from normal tissues. Conventional MRI does not supply any quantitative value, whereas DTI provides molecular information for both healthy and leukoaraiosis areas.