MRI and pathological examination of post-mortem brains: the problem of white matter high signal areas

181

116

Background and Purpose-Most previous studies addressed the cognitive impact of lacunar infarcts using radiologic correlations that are known to correlate poorly with neuropathological data. Moreover, absence of systematic bilateral assessment of vascular lesions and masking effects of Alzheimer disease pathology and macrovascular lesions may explain discrepancies among previous reports. To define the relative contribution of silent lacunes to cognitive decline, we performed a detailed analysis of lacunar and microvascular pathology in both cortical and subcortical areas of 72 elderly individuals without significant neurofibrillary tangle pathology or macrovascular lesions. Methods-Cognitive status was assessed prospectively using the Clinical Dementia Rating (CDR) scale; neuropathological evaluation included A␤-protein deposition staging and bilateral assessment of microvascular ischemic pathology and lacunes; statistical analysis included multivariate models controlling for age, amyloid deposits, and microvascular pathology. Results-Thalamic and basal ganglia lacunes were negatively associated with CDR scores; cortical microinfarcts, periventricular and diffuse white matter demyelination also significantly affected cognition. In a multivariate model, cortical microinfarcts and thalamic and basal ganglia lacunes explained 22% of CDR variability; amyloid deposits and microvascular pathology explained 12%, and the assessment of thalamic and basal ganglia lacunes added an extra 17%. Deep white matter lacunes were not related to cognitive status in univariate and multivariate models. Conclusions-In

Section: Discussionsupporting

confidence: 56%

Cognitive Consequences of Thalamic, Basal Ganglia, and Deep White Matter Lacunes in Brain Aging and Dementia

Gold

Kovari

Herrmann

et al. 2005

181

116

“…These include enlarged perivascular (Virchow-Robin) spaces, as well as degeneration of myelin and axons with increased intracellular and extracellular water content, gliosis, and even infarction. [1][2][3][4][5][6][7][8][9][10] The clinical significance of WMC has not been fully elucidated. There is a relationship between several cerebrovascular risk factors and the presence of WMC.…”

mentioning

confidence: 99%

A New Rating Scale for Age-Related White Matter Changes Applicable to MRI and CT

Wahlund

Barkhof

Fazekas

et al. 2001

1,584

1,151

on behalf of the European Task Force on Age-Related White Matter Changes Background and Purpose-MRI is more sensitive than CT for detection of age-related white matter changes (ARWMC).Most rating scales estimate the degree and distribution of ARWMC either on CT or on MRI, and they differ in many aspects. This makes it difficult to compare CT and MRI studies. To be able to study the evolution and possible effect of drug treatment on ARWMC in large patient samples, it is necessary to have a rating scale constructed for both MRI and CT. We have developed and evaluated a new scale and studied ARWMC in a large number of patients examined with both MRI and CT. Methods-Seventy-seven patients with ARWMC on either CT or MRI were recruited and a complementary examination (MRI or CT) performed. The patients came from 4 centers in Europe, and the scans were rated by 4 raters on 1 occasion with the new ARWMC rating scale. The interrater reliability was evaluated by using statistics. The degree and distribution of ARWMC in CT and MRI scans were compared in different brain areas. Results-Interrater reliability was good for MRI (ϭ0.67) and moderate for CT (ϭ0.48). MRI was superior in detection of small ARWMC, whereas larger lesions were detected equally well with both CT and MRI. In the parieto-occipital and infratentorial areas, MRI detected significantly more ARWMC than did CT. In the frontal area and basal ganglia, no differences between modalities were found. When a fluid-attenuated inversion recovery sequence was used, MRI detected significantly more lesions than CT in frontal and parieto-occipital areas. No differences were found in basal ganglia and infratentorial areas. Conclusions-We present a new ARWMC scale applicable to both CT and MRI that has almost equal sensitivity, except for certain regions. The interrater reliability was slightly better for MRI, as was the detectability of small lesions. Key Words: dementia Ⅲ magnetic resonance imaging Ⅲ rating scales Ⅲ tomography, x-ray computed Ⅲ white matter W hite matter changes (WMC) are defined as areas with high signal intensities on T2-weighted MRI and as areas with low attenuation on CT. The mechanisms for development of WMC are not fully understood, but several histopathologic correlates have been reported. These include enlarged perivascular (Virchow-Robin) spaces, as well as degeneration of myelin and axons with increased intracellular and extracellular water content, gliosis, and even infarction. [1][2][3][4][5][6][7][8][9][10] The clinical significance of WMC has not been fully elucidated. There is a relationship between several cerebrovascular risk factors and the presence of WMC. One of the strongest risk factors, apart from hypertension, is that of age. 11-13 Henceforth, we will designate WMC as "age-related white matter changes" (ARWMC).There is also evidence for a relationship between ARWMC and cognitive impairment in demented patients 14 -16 as well as in healthy elderly individuals. 13,[17][18][19] However, the extent of this association is still controv...

“…MRI pathological correlations of WMH also suggest differences between PVWMH and DWMH. 9,[17][18][19][20][21][22][23][24][25][26] However, within both types of WMH lesions, there is vascular fibrosis and lipohyalinosis, 9,22,23,[25][26][27] supporting a common ischemic vascular pathological mechanism for WMH among older individuals. 17,24,25 Therefore, whereas qualitative MRI studies generally support distinctions between PVWMH and DWMH, pathological studies suggest that both types of WMH share the same ischemic etiology supporting pathological linkage.…”

mentioning

confidence: 99%

Anatomical Mapping of White Matter Hyperintensities (WMH)

DeCarli

Fletcher

Ramey

et al. 2005

442

255