ABSTRACT Leukoaraiosis describes diffuse white matter abnormalities on CT or MR brain scans, often seen in the normal elderly and in association with vascular risk factors such as hypertension, or in the context of cognitive impairment. The term was introduced to avoid confusing an imaging appearance with a specific pathology. Neurologists often come across this appearance, but its significance is sometimes uncertain. The effects on cognitive function and gait are insidious and can be difficult to detect at the bedside, but are nevertheless important. However, gradually it is becoming clearer how leukoaraiosis relates to cerebrovascular disease, Alzheimer's and other diseases, and how this appearance should influence treatment decisions.
SourceAvailable from: Joel Ramirez[Show abstract] [Hide abstract]
ABSTRACT: Subcortical hyperintensities (SHs) are radiological entities commonly observed on magnetic resonance imaging (MRI) of patients with Alzheimer's disease (AD) and normal elderly controls. Although the presence of SH is believed to indicate some form of subcortical vasculopathy, pathological heterogeneity, methodological differences, and the contribution of brain atrophy associated with AD pathology have yielded inconsistent results in the literature. Using the Lesion Explorer (LE) MRI processing pipeline for SH quantification and brain atrophy, this study examined SH volumes of interest and cognitive function in a sample of patients with AD (n = 265) and normal elderly controls (n = 100) from the Sunnybrook Dementia Study. Compared with healthy controls, patients with AD were found to have less gray matter, less white matter, and more sulcal and ventricular cerebrospinal fluid (all significant, P <0.0001). Additionally, patients with AD had greater volumes of whole-brain SH (P <0.01), periventricular SH (pvSH) (P <0.01), deep white SH (dwSH) (P <0.05), and lacunar lesions (P <0.0001). In patients with AD, regression analyses revealed a significant association between global atrophy and pvSH (P = 0.02) and ventricular atrophy with whole-brain SH (P <0.0001). Regional volumes of interest revealed significant correlations with medial middle frontal SH volume and executive function (P <0.001) in normal controls but not in patients with AD, global pvSH volume and mental processing speed (P <0.01) in patients with AD, and left temporal SH volume and memory (P <0.01) in patients with AD. These brain-behavior relationships and correlations with brain atrophy suggest that subtle, yet measurable, signs of small vessel disease may have potential clinical relevance as targets for treatment in Alzheimer's dementia.Alzheimer's Research and Therapy 08/2014; 6(4):49. DOI:10.1186/alzrt279 · 3.50 Impact Factor
[Show abstract] [Hide abstract]
ABSTRACT: White matter lesions (WMLs) in normal elderly are related to chronic ischemia, and progression of WML occurs mostly in moderate to severe disease. However, the mechanism is uncertain. Thus, we enrolled fifty-six normal elderly patients without large artery disease. The severity of WML on MRI was graded as grade 0, I, II and III using the modified Fazekas scale. Cerebral blood flow (CBF) was measured by Xenon-CT. We found that CBF (mL/100 g/min) within periventricular lesions and in the right and left centrum semiovales were 20.33, 21.27 and 21.03, respectively, in group I; 16.33, 15.55 and 15.91, respectively, in group II; and 14.05, 14.46 and 14.23, respectively, in group III. CBF of normal-appearing white matter (NAWM) around periventricular areas and in the right and left centrum semiovales were 20.79, 22.26 and 22.15, respectively, in group 0; 21.12, 22.17 and 22.25, respectively, in group I; 18.02, 19.45 and 19.62, respectively, in group II; and 16.38, 18.18 and 16.74, respectively, in group III. Significant reductions in CBF were observed not only within lesions but also in NAWM surrounding the lesions. In addition, CBF was reduced significantly within lesions compared to NAWM of the same grade. Furthermore, CBF was reduced significantly in NAWM in grades II and III when compared to grades 0 and I. Our finding indicates that ischemia may play a role in the pathogenesis of WML. Additionally, our finding provides an alternative explanation for finding that the progression of WML occurred more commonly in patients with moderate to severe WML.PLoS ONE 11/2014; 9(11):e112832. DOI:10.1371/journal.pone.0112832 · 3.53 Impact Factor
[Show abstract] [Hide abstract]
ABSTRACT: Objective: Prior to detecting intracranial arterial stenosis, atherosclerotic wall change or plague with positive remodeling can be evaluated with high-resolution MRI (HRMRI). We prospectively evaluate atherosclerotic arterial wall change in patients without intracranial stenosis using HRMRI at 3.0 T and correlate the atherosclerotic change, cerebrovascular risk factors, and white matter hyperintensity (WMH). Methods: Patients were prospectively recruited for one year and underwent brain MRI, TOF-MRA and HRMRI using axial 3D T1 FSE of the intracranial arteries. After excluding patients with intracranial stenosis, two neuroradiologists graded the atherosclerotic change of the intracranial arterial wall on HRMRI and WMH using a 4-point scale. The relationship between atherosclerotic changes on HRMRI, cerebrovascular risk factors, and WMH were statistically evaluated. Results: Eighty-three patients without intracranial arterial stenosis were finally included. Older age (p = 0.000), hypertension (p = 0.002), and hyperlipidemia (p = 0.007) were associated with severe atherosclerotic change on HRMRI. On multivariate analysis, older age (OR: 0.114; 95% CI: 0.033-0.397; p = 0.001) and hypertension (OR: 0.178; 95% CI: 0.049-0.651; p = 0.009) were significantly associated with severe atherosclerotic change on HRMRI. The presence of moderate and severe WMH was associated with older age, hypertension, and severe atherosclerotic change on HRMRI. On multivariate analysis, atherosclerotic change on HRMRI remained the only variable significantly associated with WMH (OR: 0.086; 95% CI: 0.016-0461; p = 0.004). Conclusion: Older age and hypertension are significantly associated with intracranial atherosclerotic change on HRMRI. Atherosclerotic change detected on HRMRI may be the strongest risk factor for WMH than any other cerebrovascular risk factor in patients without intracranial stenosis.Clinical Neurology and Neurosurgery 08/2014; 126C:1-6. DOI:10.1016/j.clineuro.2014.08.010 · 1.25 Impact Factor