area, NAWM region###patients with Rankin###-Lac###CADASIL patients.
ho+Cr)###-Cr/Mettot was increased in WM hyperintensity area and NAWM of CADASIL patients.
8 HC (3M, 5F)###-Cho###patients as compared to NAWM (p<0.
Lac###-Glx/Cr and mI/Cho were increased in NAWM of CADASIL patients as compared to HC
Studies of DTI in NAWM have revealed decreased FA and increased MD in different regions that appear normal on conventional MRI, (19,20,25,34-39) suggesting the presence of microscopic pathology beyond the resolution of conventional MRI.
A recent study (39) showed significant water diffusion changes in the normal-appearing corpus callosum (NACC) in a group of patients with early MS; however, such significant abnormalities of DTI were not observed in frontal and occipital NAWM regions.
Studies in which diffusion changes measured on DTI in NAWM have been used to precede new lesion formation indicate another clinical application of DTI in terms of studying lesion pathogenesis and natural history.
In addition, macroscopic lesions of both NAWM
and normal appearing grey matter appeared to contribute to cognitive decline in these MS patients (Rovaris et al.
In two interesting MRI studies B Bodini et al (London, UK) reported that normal appearing white matter (NAWM
) damage and grey matter (GM) atrophy in early primary-progressive MS (PPMS) are independent and asked the question whether grey matter damage is secondary to damage in NAWM
or if it represents the primary target of the disease.
Several studies investigated the gene expression pattern in lesions by comparing them with either tissue from control cases, NAWM or other types of lesions (an overview of the different studies is provided in Table 1).
After an initial study comparing an acute lesion with NAWM of one MS case, Whitney et al published a second study using several lesions from two MS cases and white matter from control cases.
23-25,29) In 1979 Allen et al described several histological abnormalities in NAWM that was defined as white matter devoid of macroscopic visible plaques.