Automatic determination of white matter hyperintensity properties in relation to the development of Alzheimer's disease

Alzheimer's disease (AD) is the most common form of dementia seen in the elderly. No curing medicine for AD exists at this moment. In the search for an effective medicine, research is directed towards the prediction of conversion of mild cognitive impairment (MCI) to AD. White matter hyperintensities (WMHs) have been shown to contain information regarding the development of AD, although non-conclusive results are found in literature. These studies often use qualitative measures to describe WMHs, which is time consuming and prone to variability. To investigate the relation between WMHs and the development of AD, algorithms to automatically determine quantitative properties in terms of volume and spatial distribution of WMHs are developed and compared between normal controls and MCI subjects. MCI subjects have a significantly higher total volume of WMHs than normal controls. This difference persists when lesions are classified according to their distance to the ventricular wall. Spatial distribution is also described by defining different brain regions based on a common coordinate system. This reveals that MCI subjects have a larger WMH volume in the upper part of the brain compared to normal controls. In four subjects, the change of WMH properties over time is studied in detail. Although such a small dataset cannot be used to give definitive conclusions, the data suggests that progression of WMHs in subjects with a low lesion load is caused by an increase in the number of lesions and by the progression of juxtacortical lesions. In subjects with a larger lesion load, progression is caused by expansion of pre-existing lesions.