Computed tomography, magnetic resonance imaging and pathological correlations in a case of Binswanger's disease

The burden of microstructural damage modulates cortical activation in elderly subjects with MCI and leuko-araiosis. A DTI and fMRI study

The term leuko-araiosis (LA) describes a common chronic affection of the cerebral white matter (WM) in the elderly due to small vessel disease with variable clinical correlates. To explore whether severity of LA entails some adaptive reorganization in the cerebral cortex we evaluated with functional MRI (fMRI) the cortical activation pattern during a simple motor task in 60 subjects with mild cognitive impairment and moderate or severe (moderate-to-severe LA group, n = 46) and mild (mild LA group, n = 14) LA extension on visual rating. The microstructural damage associated with LA was measured on diffusion tensor data by computation of the mean diffusivity (MD) of the cerebral WM and by applying tract based spatial statistics (TBSS). Subjects were examined with fMRI during continuous tapping of the right dominant hand with task performance measurement. Moderate-to-severe LA group showed hyperactivation of left primary sensorimotor cortex (SM1) and right cerebellum. Regression analyses using the individual median of WM MD as explanatory variable revealed a posterior shift of activation within the left SM1 and hyperactivation of the left SMA and paracentral lobule and of the bilateral cerebellar crus. These data indicate that brain activation is modulated by increasing severity of LA with a local remapping within the SM1 and increased activity in ipsilateral nonprimary sensorimotor cortex and bilateral cerebellum. These potentially adaptive changes as well lack of contralateral cerebral hemisphere hyperactivation are in line with sparing of the U fibers and brainstem and cerebellar WM tracts and the emerging microstructual damage of the corpus callosum revealed by TBSS with increasing severity of LA.

Slowly progressive familial dementia with recurrent strokes and white matter hypodensities on CT scan

We describe 2 normotensive sisters presenting slowly progressive dementia associated with acute or subacute focal neurological symptoms, unilateral or bilateral motor signs, and dysarthria. Their father, who died in the seventh decade, had a similar clinical picture. Computerized axial tomography (CT) scan of the head showed symmetrical hypodensities in the periventricular white matter and mild to moderate hydrocephalus. In these patients a diagnosis of Binswanger's disease was based on the clinical features supported by white matter changes on CT scan. Our study suggests that genetic factors may play a role in the etiology of Binswanger's disease.

Leukoaraiosis: a reappraisal. II. MRI studies

Magnetic resonance imaging is more sensitive than computed tomography to brain white matter changes of undefined significance observed in elderly subjects termed leuko-araiosis. Cross-sectional clinical studies have shown that these changes are more frequent or are more extensive in patients with cerebrovascular disease or vascular risk factors. Pathological studies have revealed that a number of alterations may underlie focal white matter changes including complete and incomplete lacunar infarcts, état criblé, dilated perivascular (Virchow-Robin) spaces, demyelination, and gliosis. Diffuse white matter changes are more difficult to explain. These might result from confluence of focal changes, or from diffuse white matter ischemia (incomplete infarct). Alternatively, they may be related to alterations of the transependymal CSF flow. Longitudinal studies in asymptomatic subjects correlating the MRI picture with clinical, pathophysiological, and histopathological data are needed in order to establish the significance and prognostic value of the different processes underlying LA, and to plan therapeutic strategies to prevent or treat them.

Leuko-araiosis: a reappraisal. I. CT studies

Leuko-araiosis is a purely descriptive term indicating images of bilateral, patchy or diffuse areas of decreased density frequently observable in the deep white matter on brain CT scans of adults and elderly subjects. While in earlier studies these images were considered as the "in vivo" expression of leukoencephalopathy associated with Binswanger disease, subsequently they have been reported in a rather broad spectrum of clinical conditions, including healthy aging and dementia of different types. Evidence of arterial hypertension and lacunar stroke is found in only two-thirds of subjects with leuko-araiosis. The results of pathological studies are conflicting about the nature of leukoencephalopathy, and the type and severity of medullary artery involvements. Probably several mechanisms underlie leuko-araiosis. They might act separately or be combined in different cases. Classification by physiopathological mechanism may be a suitable aim of future research in this field.