Comparison of postmortem magnetic resonance imaging and neuropathologic findings in the cerebral white matter

Comparison of the pathology of cerebral white matter with post-mortem magnetic resonance imaging (MRI) in the elderly brain

White matter lesions (WML) on magnetic resonance imaging (MRI) brain scans are associated with ageing. They are unrelated to specific disorders, and their impact on cognitive and other brain functions is poorly characterized. Pathological studies often omit systematic survey of WML because of the need to study multiple full coronal tissue blocks, and uncertainty over the significance of lesions identified in periventricular and deep subcortical regions. Post-mortem MRI provides a means of mapping WML but the sensitivity and specificity of the method are unresolved. In this study post-mortem MRI of WML in fixed brain slices was compared with pathology in 33 brains donated to the Medical Research Council Cognitive Function and Ageing Study (MRC CFAS). This study shows that MRI detection of WML was less sensitive than pathology: periventricaular lesions (PVL) sensitivity = 95% (87-99%), specificity = 71% (44-90%); deep subcortical lesions (DSCL) sensitivity = 86% (79-93%), specificity = 80% (72-88%). False negative MRI was associated with milder pathology, but lesions detected by myelin attenuation alone showed both microglial and endothelial activation. Therefore post-mortem MRI of formalin-fixed brain slices is a reliable method to obtain systematic data on the severity and distribution of cerebral white matter disease, and appears to detect those WML most likely to have clinical impact.

Postmortem MR imaging of formalin-fixed human brain

High-resolution postmortem neuroimaging of the brain can play a role in research programs by providing archival and reslicable images of brain specimens before permanent sectioning. These images can supplement evidence attained from both traditional neuropathological observations and in vivo neuroimaging. Differential brain tissue conspicuity, detectable with MRI, is determined by the density and mobility of water protons. Water content is about 70% in white matter, 80% in gray matter, and 99% in cerebrospinal fluid (CSF). To the extent that brain tissue contrast is determined by the number and microenvironment of water protons, timing parameters of MR image acquisition can interrogate this environment. Because the chemical environment of protons is different in living from dead tissue, optimal temporal imaging parameters, for example, for spin-echo imaging, commonly used for in vivo clinical and research study are different from those best for postmortem imaging. Here, we present a series of observations to identify relaxation times and optimal parameters for high-resolution structural imaging of formalin-fixed postmortem brain tissue using commercially available clinical scanners and protocols. Examples of high-resolution images and results from attempts at diffusion imaging are presented.

Glial levels determine severity of white matter disease in Alzheimer's disease: a neuropathological study of glial changes

The morphological components of cerebral white matter disease (WMD) were studied in 17 cases of clinically diagnosed dementia and neuropathologically verified Alzheimer's disease (AD) with concomitant WMD. The distribution of grey and white matter changes was evaluated and overall as well as regional severity was graded. Total glial numbers in frontal white matter were counted using a light microscope. Oligodendrocyte and astrocyte quantities as well as astrocytic reactivity were assessed from frontal and parietal lobe white matter using a computer assisted morphometric method. The AD-WMD group was compared with 10 nondemented age-matched controls. Astrocyte/oligodendrocyte ratio (AOR) was calculated, total glial counts and AOR were compared with severity of WMD, and Alzheimer encephalopathy grade was subjectively assessed. Astrocytic numbers, AOR and astrocytic reactivity proved to be significantly higher in the demented group, whereas oligodendrocytic and total glial counts were significantly lower. Furthermore, AOR proved to be positively correlated with severity of WMD, whereas no association was found with Alzheimer encephalopathy. We conclude that WMD in dementia, for example, of the type seen in AD, can easily be detected, measured and graded quantitatively, with AOR being a significant indicator of the severity of changes. This could serve as a tool for differentiating white matter pathologies in dementia and may be the basis for recognition of the mildest white matter changes with new imaging methods, and enable potential clinical intervention.

A robust method for extraction and automatic segmentation of brain images

A new protocol is introduced for brain extraction and automatic tissue segmentation of MR images. For the brain extraction algorithm, proton density and T2-weighted images are used to generate a brain mask encompassing the full intracranial cavity. Segmentation of brain tissues into gray matter (GM), white matter (WM), and cerebral spinal fluid (CSF) is accomplished on a T1-weighted image after applying the brain mask. The fully automatic segmentation algorithm is histogram-based and uses the Expectation Maximization algorithm to model a four-Gaussian mixture for both global and local histograms. The means of the local Gaussians for GM, WM, and CSF are used to set local thresholds for tissue classification. Reproducibility of the extraction procedure was excellent, with average variation in intracranial capacity (TIC) of 0.13 and 0.66% TIC in 12 healthy normal and 33 Alzheimer brains, respectively. Repeatability of the segmentation algorithm, tested on healthy normal images, indicated scan-rescan differences in global tissue volumes of less than 0.30% TIC. Reproducibility at the regional level was established by comparing segmentation results within the 12 major Talairach subdivisions. Accuracy of the algorithm was tested on a digital brain phantom, and errors were less than 1% of the phantom volume. Maximal Type I and Type II classification errors were low, ranging between 2.2 and 4.3% of phantom volume. The algorithm was also insensitive to variation in parameter initialization values. The protocol is robust, fast, and its success in segmenting normal as well as diseased brains makes it an attractive clinical application.

Magnetic resonance imaging in dementia. A study of brain white matter changes

Non-specific white matter changes (WMC) in the brain are common findings in the elderly population. Although they are frequently seen in non-demented persons, WMC seem to be more common in demented patients. The significance of these changes, as well as their pathophysiological background, is incompletely understood. The aim of this thesis was to study different aspects of WMC using MR imaging (MRI) and to investigate the clinical significance of such changes in subjects with mild cognitive impairment or dementia. In study I post-mortem MRI of the brain was compared to corresponding neuropathology slices. WMC were quantified and found to be more extensive on neuropathology. The areas that appeared normal on MRI but not on histopathology represented only minor changes with increased distance between the myelinated fibres but with preserved axonal network and glial cell density. Study II evaluated the blood-brain barrier (BBB) integrity to investigate if an increased permeability could be shown in WMC. A contrast-enhanced MRI technique was used to detect small degrees of enhancement. No general increase in BBB could be detected in the WMC areas. In study III the relation between WMC and apolipoprotein E (APOE) genotype was explored in patients with Alzheimer's disease (AD). Results showed that AD patients, who were homozygous for the APOE epsilon 4 allele had more WMC than patients with other genotypes. This was most significant for changes in the deep white matter. Results also indicated that in AD patients carrying the epsilon 4 allele, WMC are not age-related phenomena, but might be related to the aetiology of the disease. Study IV aimed to investigate if WMC in a specific brain region affect cognitive functions related to that area. Periventricular WMC in the left frontal lobe predicted a decrease in initial word fluency, a test though to reflect left frontal lobe functioning. This indicates that WMC might have specific effects in different brain regions. In study V we evaluated the prognostic significance of WMC in patients with memory impairment, regarding the rate of further global cognitive decline. There was no difference in outcome between patients having extensive WMC and a matched control group, during 2-4 years of follow up, and assessed by the "Mini-Mental State Examination". In conclusion, this work has shown and characterised pathological changes in the white matter not visible on conventional MRI. We have also shown that there is no major general increase in BBB permeability in areas of WMC. In addition, homozygosity with regard to the APOE epsilon 4 gene allele implies an increased extent of WMC in AD patients. In AD patients carrying this gene allele, WMC are not merely age-related phenomena, but might be related to the aetiology of the disease. We also claim that WMC in a specific location might impair cognitive functions that rely on those specific pathways. In contrast, WMC do not seem to have any prognostic value in predicting the rate of global cognitive decline in patients at a memory clinic.

White matter hyperintensity volume in late-onset and early-onset schizophrenia

BACKGROUND

Late life onset schizophrenia (sometimes termed "late paraphrenia") has been theorized to be due to neuro-degenerative processes affecting individuals with latent vulnerability to schizophrenia. However, neuro-imaging studies using computed tomography (CT) and magnetic resonance imaging (MRI) investigating possible degenerative anatomic correlates (atrophy, white matter disease, and strokes) to late onset psychoses have yielded conflicting findings. The variation in these findings may be due to differences in study design, case ascertainment, and measurement methods.

OBJECTIVE

The present study compares a continuous measure of total volume of white matter hyperintensities (WMHs) in age, race, and gender-ratio matched groups of late-onset schizophrenic, elderly, early-onset schizophrenic and control subjects.

METHOD

Our method of WMH measurement yielded an explicit volume and is an alternative to frequently used ordinal measures.

RESULTS

We found no significant differences in the WMH volumes between these three groups. This finding is consistent with a prior study (Symonds et al., 1997. J Neuropsychiat Clin Neurosci 9: 251 - 258), that used ordinal measures.

Neuroimaging in dementia

Positron emission tomography, single photon emission computed tomography, and MR imaging are brain imaging techniques that have been applied widely to the study of patients with dementia. This article reviews current data on the clinical use of these techniques in the differential diagnosis of dementia and the prediction of dementia in those at risk.

MRI findings differentiate between late-onset schizophrenia and late-life mood disorder

OBJECTIVES

Compare MRI scans of patients with late-onset schizophrenia, late-life depression and late-life bipolar disorder to age- and gender-matched controls. MRI head scans of 14 patients in each diagnostic group and 21 patients in the normal control group were compared. Subjects were recruited from inpatient and outpatient services.

MEASURES

The CERAD MRI rating algorithm was used to rate degree of atrophy.

RESULTS

Patients with bipolar and unipolar disorder had greater left sylvian fissure and left and right temporal sulcal enlargement, and more bilateral cortical atrophy than normals. Patients with late-onset schizophrenia had larger right temporal horns and larger third ventricles. These findings validate the distinctions between late-life affective disorder and late-onset schizophrenia and mirror changes reported in younger individuals. They may reflect underlying structural and functional abnormalities found in neuropathologic and functional imaging studies.

Relationship between depression and cerebrovascular disease: conceptual issues

OBJECTIVES

The association between cerebrovascular disease (CVD) and depression has been well described, but our understanding of various aspects of the relationship between these two disorders remains limited.

METHOD

Based on a selective literature review, this paper examines empirical evidence and discusses conceptual issues concerning hierarchical, interactive, and co-morbid relationships between CVD and depression.

RESULTS

The concept of vascular depression minimizes the importance of the contribution of psychosocial factors. The interactive and co-morbid relationships have been largely neglected in psychiatric research. There is evidence that depression may increase the risk of CVD morbidity in patients with vascular disease and delay recovery in stroke patients, implying an interactive relationship. The concurrent existence of these two disorders based on common etiological factors such as genetic vulnerability, alcoholism and personality traits seems plausible.

CONCLUSIONS

A modified comorbidity model may guide investigation into the hierarchical, interactive and common etiological relationships between CVD and depression.

Quantitative study of signal hyperintensities on T2-weighted magnetic resonance imaging in late-onset schizophrenia

OBJECTIVE

The authors investigated the extent and distribution of signal hyperintensities on T2-weighted magnetic resonance imaging (MRI) of the brains of subjects with late-onset schizophrenia.

METHOD

The study group consisted of 25 subjects with DSM-III-R schizophrenia and onset at age 50 or more years (late-onset schizophrenia) matched group-wise with 24 subjects with early-onset schizophrenia and 30 psychiatrically healthy volunteers. The subjects underwent clinical and neuropsychological assessments and MRI scans. Transaxial T2-weighted and proton-density images were analyzed manually for signal hyperintensities in cerebral and cerebellar white matter, the basal ganglia, thalamus, and brainstem, and quantitative measures were obtained.

RESULTS

Subjects with late-onset schizophrenia had greater periventricular hyperintensities measured as widths of periventricular rims and frontal and occipital caps than the two comparison groups. Hyperintense signals elsewhere in the white matter and in the basal ganglia and brainstem did not differ between groups, but the late-onset schizophrenia group had more signal hyperintensities in the thalamus than the normal comparison group. Signal hyperintensities in the frontal-subcortical circuit regions, when considered together, did not differ between groups. Periventricular hyperintensities had significant negative correlations with intelligence, memory, and frontal-executive functioning in the total group.

CONCLUSIONS

The finding of increased periventricular hyperintensities and thalamic signal hyperintensities in late-onset schizophrenia suggests the possibility that cerebrovascular disease, in an interaction with some incompletely understood vulnerability factors, may play a role in the pathogenesis of schizophrenia with onset in advanced age.

Impaired cerebrovascular reactivity as a risk marker for first-ever lacunar infarction: A case-control study

BACKGROUND AND PURPOSE

Functional assessment of small arteries and arterioles could provide valuable information regarding the extent of diffuse arteriolosclerosis in patients with small-vessel disease. Therefore we attempted to clarify the role of cerebrovascular reactivity (CVR) as a risk marker for first-ever symptomatic lacunar infarction.

METHODS

Forty-six patients with lacunar infarction and 46 sex- and age-matched control subjects were prospectively evaluated. Cerebral hemodynamics were studied with transcranial Doppler ultrasonography. CVR was examined by calculating the percent increase in mean flow velocity occurring after 15 mg/kg acetazolamide administration (Diamox test).

RESULTS

CVR was significantly (P<0.0001, Student's t test) lower in cases (50.0+/-12. 7%) as compared with control subjects (65.2+/-12.4%). A multiple logistic regression analysis identified male sex (odds ratio [OR] 2. 3, P=0.02), age (OR 3.6, P<0.005), and the presence of lacunar infarction on magnetic resonance imaging (OR 5.3, P<0.001) as significant and independent factors associated with a reduction of CVR. Moreover, a cut-point of 55.6% (sensitivity 67%, specificity 82%) was established as the threshold value for distinguishing between pathological and normal CVR. CVR was significantly (P=0.02) lower in patients with multiple (46.38+/-12.6%) than with single (54. 83+/-11.58%) lacunar infarction. In addition, a trend of negative correlation was found between CVR and the number of lacunar infarctions (r=-0.26, P=0.08). In the multiple logistic model, history of hypertension (OR 7.24; 95% confidence interval 2.95 to 17. 79) and CVR (OR 0.8; 95% confidence interval 0.81 to 0.93) emerge as significant and independent predictors of first-ever lacunar infarction.

CONCLUSIONS

These data suggest that impaired CVR is a risk marker for first-ever lacunar infarction.

Visualizing and characterizing white matter fiber structure and architecture in the human pyramidal tract using diffusion tensor MRI

We used diffusion tensor imaging to assess diffusion anisotropy in the pyramidal tract in ten young, and ten elderly subjects (five males and five females in each group). The purpose of this study was to define normative values for anisotropy at different anatomic levels of the brainstem as well as to assess differences due to age, gender, and laterality. In all subjects, anisotropy was highest in the cerebral peduncle, lowest in the caudal pons, and intermediate in the medulla. In the pons and medulla the regional variability was high, with significant differences in anisotropy even between contiguous slices. Multifactorial ANOVA (performed using the average value of anisotropy within each region of interest) revealed that elderly subjects had significantly lower values than young subjects in the cerebral peduncle, with no differences in the pons and medulla. No significant differences in anisotropy due to gender and side were found. The differences in anisotropy at different levels of the brainstem reflect differences in the local architecture of white matter fibers. Anisotropy is high in the cerebral peduncle because fibers have a highly ordered arrangement, while in the pons and medulla, anisotropy is lower because the local fiber architecture is less coherent due to the presence of other fibers and nuclei. The biologic meaning of the intergroup differences in anisotropy is discussed in light of the structure and architecture of the tissue under investigation. We also consider potential sources of artifacts, such as noise and motion, partial volume contamination, anatomic mismatching, and the use of inappropriate statistical tests. We conclude that the age-related decrease in anisotropy in the cerebral peduncle is not artifactual but rather reflects subtle structural changes of the aging white matter. Our study however shows that caution must be exercised in interpreting diffusion anisotropy data.

Basal ganglia alterations and brain atrophy in Huntington's disease depicted by transcranial real time sonography

OBJECTIVES AND METHODS

Transcranial real time sonography (TCS) was applied to 49 patients with Huntington's disease and 39 control subjects to visualise alterations in the echotexture of the basal ganglia. For comparison T1 weighted, T2 weighted, and fast spin echo MRI was performed in 12 patients with Huntington's disease with and in nine patients without alterations of the basal ganglia echotexture as detected by TCS and T1 weighted, T2 weighted, and fast spin echo MRI. Furthermore, the widths of the frontal horns, third ventricle, and the lateral ventricles were depicted in TCS examinations and correlations examined with corresponding CT slices.

RESULTS

Eighteen out of 45 (40%) of the patients with Huntington's disease with adequate insonation conditions showed hyperechogenic lesions of at least one basal ganglia region. In 12 patients TCS depicted hyperechogenic lesions of the substantia nigra; in six patients the head of the caudate nucleus was affected. The lentiform nucleus (n=3) and the thalamus (n=0) were less often affected or spared. Hyperechogenic lesions were significantly more frequent in patients with Huntington's disease than in 39 control subjects, who had alterations of the echotexture in 12.8% (4/39) of the examinations. The number of CAG repeats and the clinical status correlated with the identification of hyperechogenic lesions of the substantia nigra (p<0.01). Hyperechogenic lesions of the caudate nucleus were associated with an increased signal intensity in T2 weighted MR images (p<0.05). All TCS parameters indicating brain atrophy correlated with CT findings (p<0.0001).

CONCLUSIONS

TCS detects primarily abnormalities of the caudate nucleus and substantia nigra in Huntington's disease. These changes in the echotexture may represent degenerative changes in the basal ganglia matrix and are partially associated with CAG repeat expansion and the severity of clinical findings.

Cerebrovascular risk factors and depression in older primary care patients: testing a vascular brain disease model of depression

The authors examined whether cerebrovascular risk factors (CVRFs) are associated with depressive diagnoses and symptoms in 303 primary-care patients age >/=60 years, as would be consistent with a small-vessel brain disease model of later-life depression. CVRFs were not significantly independently associated with major, minor, or subsyndromal depression, late-onset major depression, or overall depressive symptom severity. These data did not support the notion that a small-vessel brain disease model of depression might apply to the majority of older persons with depressive symptoms and syndromes in primary-care settings. Future work should include longitudinal study with larger sample sizes.

The spectrum of age-associated brain abnormalities: their measurement and histopathological correlates

Magnetic resonance imaging (MRI) has dramatically increased our ability to detect morphological abnormalities in relation to aging of the brain. Among those changes are alterations of the white matter which display high signal intensity on both proton density and T2-weighted images. They may be seen in the deep and subcortical white matter or in a periventricular location. In clinically asymptomatic individuals the reported prevalence ranges from 20% to 60% for deep and subcortical white matter hyperintensities and from 15% to 94% for periventricular changes. Besides different characteristics of the populations examined these wide ranges are a consequence of quite diverse rating schemes and measurement approaches. Inadequate grading of MRI hyperintensities may also explain some of the inconsistencies in the reported associations of white matter damage with cerebrovascular risk factors or cognitive functions. Therefore development of a commonly accepted rating scheme would be desirable. Histopathologic observations could lay the basis. Hyperintense periventricular capping of the frontal horns and a smooth halo of periventricular hyperintensity have been linked to disruption of the ependymal lining, subependymal gliosis and concomitant loss of myelin. Punctate lesions in the deep and subcortical white matter corresponded to minor perivascular reduction in myelin content possibly because of a lower permeability of thickened arteriolar walls. Larger patchy and confluent hyperintensities, however, appear to indicate more extensive ischemic damage consistent with advanced microangiopathy. In parallel, newer MRI techniques may also contribute to the delineation and separation of these various types of tissue alteration.

Patterns of regional cortical dysmorphology distinguishing schizophrenia and chronic alcoholism

BACKGROUND

This study used magnetic resonance imaging (MRI) to compare the extent and pattern of tissue volume deficit and cerebrospinal fluid volume enlargement in chronic alcoholics and schizophrenics.

METHODS

The subjects included 62 detoxified chronic alcoholics (26-63 years), 71 schizophrenics (23-63 years), and 73 controls spanning the adult age range (21-70 years). MRI volumes were adjusted for normal variation in head size and age established from the control group.

RESULTS

Both patient groups showed widespread cortical gray matter volume deficits compared with controls, but only the alcoholics had white matter volume deficits. The schizophrenics had significantly greater volume deficits in the prefrontal and anterior superior temporal gray matter than in the more posterior cortical regions. By contrast, the deficits in the alcoholics were relatively homogeneous across the cortex. For white matter, the deficits in the alcoholics were greatest in the prefrontal and temporal-parietal regions. Although both patient groups had abnormally larger cortical sulci and lateral and third ventricles than the controls, the alcoholics had significantly larger sulcal volumes in the frontal, anterior, and posterior parietal-occipital regions than the schizophrenics.

CONCLUSIONS

This quantitative MRI study revealed different patterns of regional cortical volume abnormalities in schizophrenics and alcoholics. The schizophrenic group exhibited cortical gray matter volume deficits of modestly greater magnitude than that observed in the alcoholic group, and the alcoholics but not the schizophrenics exhibited cortical white matter volume deficits.

Structural changes in the brain of patients with bipolar affective disorder by MRI: a review of the literature

1. Current literature was searched to evaluate the use of magnetic resonance imaging in patients with bipolar disorder. 2. The presence of white matter hyperintensities, differences in temporal lobe and hippocampal structures, and ventricular enlargement in patients with bipolar disorder was assessed. 3. Further use of MRI in patients with bipolar disorder is reviewed.

Alterations in glia and axons in the brains of Binswanger's disease patients

BACKGROUND AND PURPOSE

Although increasing attention is being paid to Binswanger's disease, a form of vascular dementia characterized by diffuse white matter lesions, only limited information is available on the pathological changes that occur in the glia and axons in the white matter. We therefore investigated the brains of patients with Binswanger's disease to gain further insight into its pathophysiology.

METHODS

Autopsied brains from patients with Binswanger's disease (group 3; n = 17) were compared with those of nonneurological controls (group 1; n = 5) and controls with large cortical infarcts but without significant white matter lesions (group 2; n = 5). Glial fibrillary acidic protein (GFAP) was used as an immunohistochemical marker for astroglia, leukocyte common antigen (LCA) was used as a marker for microglia, and HLA-DR was used as a marker for activated microglia. Axonal damage was assessed by the accumulation of proteins, which are transported by fast axonal flow, amyloid protein precursor (APP), synaptophysin, and chromogranin A.

RESULTS

Although there was no difference in numerical density of GFAP-immunoreactive astroglia in each group, regressive astroglia were observed in 7 of 17 patients with Binswanger's disease. LCA-immunoreactive microglia were 1.7 times more numerous in Binswanger's disease than in group 1 (P < .05). HLA-DR-immunoreactive-activated microglia were 3.4 times and 2.1 times more numerous in Binswanger's disease as compared with group 1 (P < .01) and group 2 (P < .05), respectively. There was frequent perivascular lymphocyte cuffing, and clusters of macrophages with a decreased number of oligodendroglia were observed in the rarefied white matter. The grading scores for the number of axons immunoreactive for either APP, synaptophysin, or chromogranin A were significantly higher in Binswanger's disease than in group 1 or 2.

CONCLUSIONS

The pathological alterations in Binswanger's diseased brains include regressive changes in the astroglia and activation of the microglia with a decrease in the oligodendroglia, which were associated with the degradation of both myelin and axonal components. These results indicate that an inflammatory reaction and compromised axonal transport, mediated by chronic ischemia, may play an important role in the pathophysiology of Binswanger's disease.

Quantitative magnetic resonance analysis in vascular dementia

The potential role of magnetic resonance imaging (MRI) in differentiating between specific causes of cognitive decline in patients with vascular dementia (VD) has not yet been fully established. We therefore decided to assess the supratentorial cerebral contents in 24 patients with a diagnosis of probable VD and in 24 normal subjects, matched for age and education level, using MRI volumetric parameters obtained by means of a quantitative method. The volumes of subarachnoid and ventricular spaces, cerebral tissue, and hyperintense areas on T2-weighted images were calculated. In order to reduce interindividual variability caused by differences in intracranial size, each absolute measurement was normalized to the relative size of the intracranial volume. In addition, we calculated the ratio between the areas of the corpus callosum (CC) and supratentorial brain at the same level on the T1-weighted image midsagittal plane. The MRI data were correlated with the deterioration of cognitive functions. Patients with VD showed significantly lower cerebral tissue volume and CC area, and higher ventricular space volume than normal subjects. Furthermore, the total volume of the T2 signal alterations was higher in VD patients than in normal subjects. In VD patients, this volume was found to be proportional to the increase in the volume of the ventricular space. On the other hand, no correlation was found between the volume of the T2 signal alterations and the area of the CC. The degree of global cognitive dysfunction and the score of each neuropsychological test did not show any correlation with the MRI data. Our results suggest that ventricular enlargement in VD patients is correlated with the increase in volume of the T2 signal abnormalities, but that the degree of global cognitive dysfunction is not influenced by the volume of these T2 signal abnormalities. Furthermore, the CC atrophy does not influence the score of any neuropsychological test or the degree of global cognitive dysfunction.

The anatomy of mood disorders--review of structural neuroimaging studies

The structural neuroimaging findings in mood disorders were reviewed, to evaluate evidence for a neuroanatomic model of pathophysiology, involving the prefrontal cortex, the basal ganglia, the amygdala-hippocampus complex, thalamus, and connections among these structures. Global atrophy is not consistently found. The best replicated finding is an increased rate of white matter and periventricular hyperintensities. A smaller frontal lobe, cerebellum, caudate, and putamen appear present in unipolar depression. A larger third ventricle, and smaller cerebellum and perhaps temporal lobe appear present in bipolar disorder. These localized structural changes involve regions that may be critical in the pathogenesis of mood disorders. Generalized and localized anatomic alterations may be related to age or vascular disease. The clinical and biological correlates of these changes need to be investigated to allow development of a more complete model of pathophysiology of mood disorders.

Alterations of the blood-brain barrier and glial cells in white-matter lesions in cerebrovascular and Alzheimer's disease patients

BACKGROUND AND PURPOSE

The underlying cause of white-matter lesions, which are frequent findings in cerebrovascular disease (CVD) and Alzheimer's disease (AD), remains uncertain. We performed immunohistochemical analysis of serum protein extravasation to investigate the function of the blood-brain barrier in white-matter lesions.

METHODS

White-matter lesions were estimated by use of Kluver-Barrera staining in patients diagnosed clinicopathologically as having ischemic CVD (n = 14) and AD (n = 12) and from nonneurological control subjects (n = 6). Axonal damages were investigated by use of immunohistochemistry for amyloid protein precursor. Alteration of the blood-brain barrier was examined with fibrinogen and immunoglobulins used as markers. The numbers of HLA-DR-positive microglia and glial fibrillary acidic protein-positive astroglia were examined comparatively.

RESULTS

White-matter lesions were graded as normal (grade 0) in 14 of the 32 cases (44%), slight (grade I) in 10 cases (31%), moderate (grade II) in 6 cases (19%), and severe (grade III) in 2 cases (6%). Amyloid precursor protein was accumulated most frequently in grade II white-matter lesions. Immunohistochemistry for serum proteins labeled astroglial cell bodies and their processes, which seemed to have sequestered extravasated proteins. The groups with detectable white-matter lesions had significantly higher grading scores for fibrinogen and immunoglobulins than the control group (P < .05). Although the higher scores for serum protein extravasation were statistically significant in ischemic CVD cases (P < .05), there was no significant increase in AD cases. Activated microglia and astroglia were more numerous in the groups with white-matter lesions in both ischemic CVD and AD cases, although this increase in the number of astroglia was not evident in regions with clasmatodendrosis.

CONCLUSIONS

Dysfunction of the blood-brain barrier is more prominent in white-matter lesions seen in ischemic CVD than in AD and may have a role in the pathogenesis of cerebrovascular white-matter lesions.

Risk factors and leukoaraiosis in stroke patients

OBJECTIVES

Although leukoaraosis (LA) is a common CT findings, its pathogenesis remains debated: if small-artery pathology may explain in some cases white matter changes, many other factors, such as hemodynamic perturbations, might also lead to LA. To test these hypothesis, we determined the types of cerebrovascular risk factors associated with leukoaraosis in consecutive patients with acute cerebrovascular event.

PATIENTS AND METHODS

Using CT-scans, we prospectively studied in 610 patients consecutively admitted for an acute cerebral event, the relation between LA and the following cerebrovascular risk factors: age, sex, arterial hypertension, diabetes mellitus, hyperlipemia, alcohol consumption, birth contraceptive pills, previous transient ischemic attack or stroke, migraine, atrial fibrillation, valvulopathy, coronaropathy, left ventricular hypertrophy, stenosis of the internal carotid artery, by means of a multiple linear regression. Relation with cerebral atrophy was also evaluated.

RESULTS

We found LA scores to depend on increasing age (p = 0.0001), female sex (p = 0.0146), history of stroke or TIA (p = 0.0051), history or current atrial fibrillation (p = 0.0083), increasing cerebral atrophy score (p = 0.0001), absence of hyperlipemia (p = 0.0003) and absence of alcohol consumption higher than 300 g/week (p = 0.0398).

CONCLUSION

Our findings do not support the hypothesis that, in stroke patients, LA share similar risk factors than small-vessel disease; other cerebrovascular risk factors may also contribute to LA, perhaps because of decreased cerebral blood flow.

Magnetic resonance imaging of Alzheimer's disease

1. Although dementia is caused by a heterogeneous group of diseases and pathologic states, Alzheimer's disease is the largest cause, estimated to account for 50 to 75% of all dementias. 2. Unfortunately, confirmation of Alzheimer's disease (AD) requires postmortem histologic confirmation; clinical diagnosis prior to death remains one of exclusion. 3. A large number of structural and volumetric MRI studies have noted anatomic and structural changes accompanying AD, including variable degrees of general cortical atrophy. 4. A classic feature reported by many MRI studies is hippocampal and temporal lobe atrophy. 5. White matter hyperintensities on MRI are common, especially in late onset AD although their significance is still controversial. 6. This article reviews the contribution of magnetic resonance to imaging the neuropathologic changes of AD, discussing both advantages and limitations, and summarizing the major findings.

Neuroleptic induced parkinsonism: MRI findings in relation to clinical course after withdrawal of neuroleptic drugs

Parkinsonism is a common complication of neuroleptic drug use; however, the pathophysiology of the persistence of parkinsonian symptoms after withdrawal of neuroleptic drugs is poorly understood. Twenty patients with neuroleptic induced parkinsonism were studied by high field MRI. Persistence of symptoms was associated with different findings depending on the age of the patients--namely, putaminal hypointensity in young patients and striatal hyperintensities in old patients. High field MRI may be useful in identifying patients at higher risk for neuroleptic induced parkinsonism.

H-1 MR spectroscopic imaging of white matter signal hyperintensities: Alzheimer disease and ischemic vascular dementia

PURPOSE

To investigate the association of white matter signal hyperintensities (WMSHs) with changes in hydrogen-1 metabolites.

MATERIALS AND METHODS

T2-weighted magnetic resonance (MR) imaging and H-1 MR spectroscopic imaging were performed in 21 elderly control subjects without or with minimal WMSHs, eight elderly subjects with substantial WMSHs, 11 probable Alzheimer disease patients with WMSHs, and eight ischemic vascular dementia (IVD) patients with WMSHs. N-acetylaspartate (NAA), choline-containing metabolites (Cho), and creatine-containing metabolites (Cr) were analyzed.

RESULTS

Differences in regional metabolite levels were found within the supraventricular brain of elderly control subjects. In Alzheimer disease patients, extensive WMSHs showed a lower percentage of NAA and a higher percentage of Cho compared with contralateral normal-appearing white matter (NAWM); in IVD patients, extensive and large WMSHs were associated with a higher percentage of Cho and a lower percentage of Cr compared with contralateral NAWM.

CONCLUSION

Regional metabolite variation and the presence of WMSHs are important covariants that must be accounted for in analysis of MR spectroscopic data.

Differences between treated and untreated hypertensive subjects in the extent of periventricular hyperintensities observed on brain MRI

BACKGROUND AND PURPOSE

Several reports have stated that the periventricular abnormalities found on T2-weighted MRI or CT are associated with age and hypertension. However, there have been no reports on the effect of hypertension treatment on white matter abnormalities. We studied the association between cardiovascular risk factors and periventricular hyperintensities (PVHs) on T2-weighted MRI and the differences between treated and untreated hypertensive subjects in the extent of PVHs.

METHODS

The extent of PVH observed on 238 MRI scans was assessed retrospectively in 238 patients older than 40 years with the use of a five-point (0 to 4) classification scale. Hypertensive subjects were divided into two groups: patients receiving no or irregular treatment and patients receiving regular treatment for hypertension.

RESULTS

Age, hypertension, treatment of hypertension, and multiple cerebral vascular lesions on MRI correlated significantly and independently with the extent of PVH. Sex and diabetes mellitus did not correlate with PVH. The Mann-Whitney U test showed significantly more extensive PVH in subjects with no or irregular treatment of hypertension compared with normotensives (2.5 +/- 0.7 versus 1.9 +/- 0.6, P < .0001) and compared with subjects receiving regular treatment of hypertension (2.5 +/- 0.7 versus 2.1 +/- 0.5, P = .0019). The latter patients had more extensive PVH than normotensives, but the difference was not significant. Mean systolic and diastolic blood pressure differed significantly among the three groups.

CONCLUSIONS

Hypertension and age were major predictors of the extent of PVH. Regular treatment for hypertension appeared to prevent the progression of PVH.

Protective effect of cyclosporin A on white matter changes in the rat brain after chronic cerebral hypoperfusion

BACKGROUND AND PURPOSE

Activation of glial cells and rarefaction of the white matter have been reported in rat brain after bilateral permanent occlusion of the common carotid arteries. Using this model, we investigated the effects of the immunosuppressant cyclosporin A on the activation of glial cells and the white matter rarefaction.

METHODS

Both common carotid arteries were ligated bilaterally in 40 male Wistar rats. Twenty-two of these rats received an intraperitoneal injection of cyclosporin A, and the remaining 18 received a vehicle-solution injection. Microglia/macrophages were investigated with immunohistochemistry for the major histocompatibility complex class I and II antigens as well as for leukocyte common antigen. Astroglia were examined with glial fibrillary acidic protein as a marker. Activation of glial cells and white matter rarefaction were then investigated from 7 to 30 days after the ligation.

RESULTS

In vehicle-treated animals, there was a persistent and extensive activation of both microglia/macrophages and astroglia in the white matter, including the optic nerve, optic tract, corpus callosum, internal capsule, and traversing fiber bundles of the caudoputamen. In cyclosporin A-treated rats, the number of activated microglia/macrophages was significantly reduced (P < .01) to approximately one fifth of that in vehicle-treated animals. Similarly, rarefaction of the white matter was much less intense in cyclosporin A-treated rats (P < .01).

CONCLUSIONS

Cyclosporin A suppressed both glial activation and white matter changes after chronic cerebral hypoperfusion. These results suggest that immunologic reaction may play a role in the pathogenesis of the white matter changes and that the present model may be useful in investigating the pathophysiology of white matter changes induced by chronic cerebral hypoperfusion.

The significance of cerebral white matter abnormalities 100 years after Binswanger's report. A review

BACKGROUND

Changes in the cerebral hemispheric white matter are detected with increasing frequency by CT and MRI among persons older than 60 years. The pathogenesis, clinical significance, and morphological substrate of these changes are incompletely understood. Patients who have such neuroimaging abnormalities are sometimes diagnosed with "Binswanger's disease," an eponym that has generated much confusion because of its imprecise meaning. The objectives of this study were to determine whether the term Binswanger's disease merits acceptance as a distinct clinicopathologic entity, to deduce the clinical significance of these white matter abnormalities from the analysis of appropriate publications, and to evaluate studies that correlate in vivo changes in the cerebral white matter with pathological features.

SUMMARY OF REVIEW

We evaluated Binswanger's original case description and, after conducting a Medline search, reviewed more than 160 publications, mostly in the English language, on the subject of white matter abnormalities detectable by currently used neuroimaging methods (ie, leukoaraiosis).

CONCLUSIONS

Binswanger's original description appears to be insufficient for the purpose of defining a new nosological entity. After evaluating the vaguely outlined pathological correlates described in a few of these subcortical cerebral leukoencephalopathies, we conclude that the clinical significance of leukoaraiosis remains incompletely defined. However, its frequency increases with age independent of other risk factors, and in nondemented subjects leukoaraiosis is associated with deficits in selected cognitive functions. Moreover, leukoaraiosis correlates with an increased risk for the subsequent development of strokes. We make specific suggestions for future studies that may help to clarify this topic.

Postmortem MRI of the brain with neuropathological correlation

We prospectively correlated in vitro MRI of the brain with the neuropathological findings in patients with suspected intracranial disease. In vitro MRI was performed on 91 consecutive formalin-fixed whole-brain specimens. In 60 cases, the images were correlated with the neuropathological findings (number of lesions, lesion boundaries, spread of oedema and type of lesions). As compared with neuropathology, MRI showed an equal number of lesions in 50 cases, more in 5, and less in 5 specimens, resulting in a sensitivity of 83.3%. The extent of perilesional oedema was better seen on in vitro MRI than on gross pathology. Microscopic extent of glial tumours was underestimated on both T2-weighted images and macroscopic examination. Neuropathology remains the reference study, since on in vitro MRI primary brain tumours, metastatic deposits and non-neoplastic space-occupying lesions cannot be differentiated. However, in our study MRI had a specificity of 76.6%. MRI of postmortem specimens is sensitive to focal brain lesions, and can focus the attention of the neuropathologist to abnormal regions.

Brain dysmorphology in adults with congenital rubella plus schizophrenialike symptoms

Brain morphology was quantified with magnetic resonance imaging (MRI) in adult patients with congenital rubella who also had schizophrenialike symptoms. MRIs were compared with those of adult early-onset schizophrenic patients without congenital rubella and age-matched healthy control subjects. The rubella patients had significantly smaller intracranial volumes and shorter stature than the schizophrenic patients or the controls; however, both patient groups had smaller cortical gray matter, but not white matter, volumes than the control group, even when the MRI volumes were corrected for head size and age. In addition, both patient groups showed significant enlargement of the lateral ventricles but not cortical sulci when compared with expected values of normal adults of the same age and head size. Overall, the pattern of dysmorphology was identical in the rubella and the schizophrenic groups. The observations in the rubella group are consistent with a developmental lesion that limits full brain growth, with the small intracranial volume due at least in part to a severe cortical gray matter volume deficit. Thus, the brain dysmorphology of congenital rubella may provide an instance of prenatal viral infection that models the schizophrenic pattern and provides indirect support for a developmental hypothesis of the neuropathogenesis of schizophrenia.

Clinical characteristics of rapidly progressive leuko-araiosis

INTRODUCTION

38 patients found to have either pure leuko-araiosis (LA) or LA combined with infarction(s) on computer tomography (CT) in 1989 were re-examined in 1992 in order to evaluate the progression of LA. The follow-up period averaged 3.2 years.

MATERIAL AND METHODS

The clinical and radiological data on patients in 1989 were collected from hospital records and re-evaluated. The patients were re-examined clinically (including 24 hour ambulatory blood pressure measurement), and neuroradiologically (CT) in 1992 for this study.

RESULTS

11 (29%) patients were found to have significant (rapid) progression of the extent of LA on CT during the follow-up. At baseline, there was no significant difference in the mean number of brain infarctions between the groups with progressing (prLA) and non-progressing LA (nprLA) or between the number of cortical and central infarctions within these groups. At follow-up, the total number of infarctions had increased significantly in both groups, but it was mostly because of the increase in cortical infarctions in the prLA group (p = 0.043) and, conversely, the central ones in the nprLA group (p = 0.011). prLA was found to be related to heart failure (82% vs 37%, p = 0.029) and atrial fibrillation (55% vs 19%, p = 0.047), whereas nprLA was strongly associated with a sudden onset of symptoms (78% vs prLA 18%, p = 0.001) like a true brain infarction. Other clinical factors, including mean blood pressure and heart rate, did not clearly differentiate between the groups.

CONCLUSION

The results suggest that there are different subgroups of patients with LA associated with various vascular factors. The occurrence of LA is not related to the distribution of infarctions. The progression of LA is not related to the number of brain infarctions or to the simultaneous increase of infarctions on CT.

Methodological problems and clinical relevance of structural neuroimaging in dementia research

Structural neuroimaging and dementia are conceptually different being only loosely correlated. Computed tomography or magnetic resonance imaging can never "prove" a clinical syndrome such as dementia, but yield clues as to its cause and the site and extent of pathological changes. Conversely, the type and degree of intellectual deterioration can hardly predict neuroradiological findings. The value of structural neuroimaging lies in detecting or excluding possible causes of dementia and quantifying linear or volumetric parameters of tissue and fluid volume. If based on a presumed or established etiology, however, specific neuropsychological and dementia syndromes may correspond to focal pathological changes seen in well-defined cerebral areas as recent investigations have shown with hippocampal atrophy in Alzheimer's dementia.

Biochemical, clinical and neuroradiological (MRI) correlations in late-detected PKU patients

Brain magnetic resonance imaging (MRI) was performed in 17 late-detected PKU patients (aged 2.8-25 years). Twelve subjects had been treated late (0.7-4.5 years), and 5 not at all. Four were still on diet when the study was performed. Mental development was normal in 4 subjects, mildly retarded in 6, and moderately or severely retarded in 7. None had exhibited mental or neurological deterioration. On MRI examination a symmetrical increase of T2-weighted signal in the periventricular white matter was found in all patients, although to different degrees. Concomitant signal decrease on the T1-weighted sequences was detected in 9 patients. Ten subjects showed focal white-matter abnormalities. A variable degree of cortical and subcortical atrophy was found in 12 subjects, and asymmetry of lateral ventricles in 4. White-matter involvement correlated with phenylalanine concentrations during the year preceding (rs = 0.5706; p < 0.02) and at the time of (rs = 0.6182, p < 0.01) the investigation. Cortical and subcortical atrophy correlated with the patient's age (rs = 0.5889, p < 0.02, and rs = 0.5929, p < 0.02, respectively). We conclude that late-detected PKU patients showed the same MRI abnormalities reported in early-treated subjects and in subjects who underwent neurological deterioration; white-matter abnormalities possibly result from the recent exposure to high phenylalanine concentrations; in late-detected PKU subjects cerebral atrophy could be the late result of chronic exposure to high phenylalanine concentrations.

Effect of white matter disease on functional connections in the aging brain

Periventricular white matter hyperintensities (PVHs) seen on T2 weighted MRI studies are common in elderly people and often represent demyelination of fibres. Damage to these fibres could lead to functional disconnection between brain regions. Electroencephalographic coherence, a measure of shared electrical activity between regions, was examined to determine if there was evidence for such disconnection. Twenty two subjects with clinically diagnosed dementia of the Alzheimer's type, 16 with multi-infarct dementia, and 18 normal controls were studied. It was hypothesised that coherence between areas presumably linked by fibres that traverse the periventricular region would be decreased in subjects with PVHs, and that PVHs would have a stronger association with decreased coherence than clinical diagnosis. It was also hypothesised that coherence between areas presumably connected by long corticocortical tracts that are neuroanatomically separated from the ventricles would be low in patients with Alzheimer's disease because of pyramidal cell death in this group, but would not be affected by the presence of PVHs. Patients with PVHs in fact had lower coherence than those without PVHs in the pre-Rolandic and post-Rolandic areas, where connecting fibres traverse the periventricular region. There was no effect of PVHs, however, on coherence between areas separated by the Rolandic fissure that were connected by long corticocortical tracts; this coherence was lowest among the patients with Alzheimer's disease. These patterns of association suggest that coherence may detect different types of neurophysiological "disconnection," and may be sensitive to selective damage to different fibre pathways.

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

We examined 21 brains from individuals more than 65 years of age by MRI and neuropathological methods to study the frequency and morphology of white matter changes. There were 16 brains from neurologically normal subjects (Group 1) while the remaining 5 (Group 2) had neurological disturbances. In Group 1 MRI showed high signal areas in the periventricular white matter in 12 brains and in the deep white matter in 9. All had focal areas, with confluent zones in 4; 3 cystic infarcts were also detected. Neuropathology in this Group showed periventricular changes of variable extent in all cases, vacuolated myelin around the perivascular spaces in 14 and degenerate myelin in 4. Macroscopic inspection showed 3 cystic lacunar infarcts, while areas of recent infarction were present on histology in 2. Four of the Group 2 brains had periventricular MRI changes; high signal areas in deep white matter were focal in 2 and confluent in 1. Cystic infarcts were detected in 3 cases. Neuropathology showed periventricular changes in all the brains; in 4 myelin around the perivascular spaces was vacuolated while degenerate myelin was demonstrated in 1. There were also old (1) and recent (2) lacunar infarcts. High signal areas in the white matter thus have different histological backgrounds but only in a minority of cases do they seem to be of pathological significance and, as a rule, they are not related to the presence of neurological disturbances. Correlative MRI-neuropathological studies are helpful for characterising abnormalities detected by techniques, like MRI, which are sensitive but not very specific.

Magnetic resonance imaging of neurodegenerative diseases

Magnetic resonance imaging (MRI) has become an important diagnostic tool in the evaluation of neurodegenerative diseases. Although MRI currently does not yield sufficient predictive power to provide a diagnosis in most individual cases, important features have been identified in population studies that help support or exclude a clinical diagnosis under consideration. In parkinsonian patients, putamenal signal hypointensity is commonly observed in patients with atypical parkinsonism. In demented patients, hippocampal atrophy and prolonged T2 relaxation may help identify individuals with Alzheimer's disease. Caudate and putamenal atrophy are seen in Huntington's disease and may serve as markers of disease progression.

[Contribution of morphological imaging in the diagnosis of dementia. I--Alzheimer disease]

In patients with Alzheimer's disease, morphological neuroimaging techniques usually reveal signs of global cerebral atrophy which gradually worsen over time and depends on age and severity of the cognitive decline. Because of the lack of artifacts and of a more appropriate angle, magnetic resonance imaging scans may visualize a prominent atrophy of the medial temporal lobes, including hippocampal structures. Hippocampal atrophy is relatively specific of Alzheimer's disease before 65 and is related to the severity of memory disorders. White matter changes in patients without cerebrovascular risk factors are not more severe in patients with presenile Alzheimer's disease than in age-matched controls. They are, however, more severe in patients with senile onset than in age-matched controls. These findings suggest that white matter changes in patients with senile onset are consistent with a diagnosis of Alzheimer's disease.

Glial activation and white matter changes in the rat brain induced by chronic cerebral hypoperfusion: an immunohistochemical study

Activation of glial cells and white matter changes (rarefaction of the white matter) induced in the rat brain by permanent bilateral occlusion of the common carotid arteries were immunohistochemically investigated up to 90 days. One day after ligation of the arteries, expression of the major histocompatibility complex (MHC) class I antigen in microglia increased in the white matter including the optic nerve, optic tract, corpus callosum, internal capsule, anterior commissure and traversing fiber bundles of the caudoputamen. After 3 days of occlusion, MHC class I antigen was still elevated and in addition MHC class II antigen and leukocyte common antigen were up-regulated in the microglia in these same regions. Astroglia, labeled with glial fibrillary acidic protein, increased in number in these regions after 7 days of occlusion. A few lymphocytes, labeled with CD4 or CD8 antibodies, were scattered in the neural parenchyma 1 h after occlusion. Activation of glial cells and infiltration of lymphocytes persisted after 90 days of occlusion in the white matter and the retinofugal pathway. However, cellular activation and infiltration in microinfarcts of the gray matter was less extensive and was substantially diminished 30 days after occlusion. The white matter changes were most intense in the optic nerve and optic tract, moderate in the medial part of the corpus callosum, internal capsule and anterior commissure, and slight in the fiber bundles of the caudoputamen. These results indicated that chronic cerebral hypoperfusion induced glial activation preferentially in the white matter. This activation seemed to be an early indicator of the subsequent changes in the white matter.

White matter hyperintensities in dementia: does it matter?

The aim of the study was to investigate whether the regional distribution of white matter hyperintensities (WMH) observed by magnetic resonance imaging differed between vascular dementia and patients with late onset Alzheimer's disease. Another aim was to investigate the relations between the occurrence and degree of WMH and clinical and laboratory data as well as measures of cognitive decline. White matter hyperintensities were assessed with a low field magnetic resonance imager on 23 subjects with probable Alzheimer's disease, 25 with possible Alzheimer's disease and 31 subjects with vascular dementia. The degree and regional distribution of the WMH (expressed as relative volumes) were calculated and compared in the three groups. The relation between cognitive impairment and the degree of the WMH was also studied. The regional distribution of the WMH differed between the groups with significantly more changes in the posterior part of the brain (p < .0001) as well as in the right hemisphere (p < .0005) in the vascular demented as compared to the patients with Alzheimer's disease. No significant correlations between cognitive impairment and the degree of the WMH were found in any of the groups. The total volume of the WMH as well as the regional distribution of these changes differed significantly between vascular dementia and Alzheimer's disease. White matter hyperintensities seem not to be related to the degree of global cognitive decline in dementia and whether it plays a causative role in the development of dementia symptoms needs to be more thoroughly investigated.

Leuko-araiosis and cerebral perfusion in normal aging

To clarify the incidence, age relationships and pathogenesis of white matter lesions of unknown origin (leuko-araiosis) detected by neuroimaging among normal elderly volunteers, we measured the severity of leuko-araiosis using computerized tomographic (CT) densitometry among 42 healthy self-supporting men and women of different ages, all with normal neurological and cognitive test performance. Results were correlated with local cerebral perfusion using xenon-contrasted CT. The 42 volunteers, who are followed in this laboratory for studies of normal aging, were divided into two groups in order to determine aging effects by an extremes design. One group consisted of 19 adults below age 60 (M = 53.3, SD = 6.0). The index group comprised 23 individuals all over the age of 60 (M = 71.6, SD = 8.7). Leuko-araiosis around the anterior horns of the lateral ventricles (frontal leuko-araiosis) was more severe (p < .01) among the older group, however, occipital leuko-araiosis did not significantly differ between older and younger groups. Cerebral perfusion in frontal, temporal, and parietal cortex was decreased among older compared with younger volunteers (ps < .001, .01, and .05, respectively). Multiple regression analyses disclosed significant and direct relationships between severity of frontal leuko-araiosis and (a) frontal cortical atrophy and (b) reductions of cerebral perfusion within frontal white matter and caudate nucleus. We conclude that cortical atrophy with hypoperfusion and ischemia of frontal white matter play a part in the pathogenesis of frontal leuko-araiosis associated with normal aging and this may be a predictor for later cognitive declines.

Incidental high-intensity foci in white matter on T2-weighted magnetic resonance imaging. Frequency and clinical significance in symptom-free adults

The clinical significance of high-intensity foci in the white matter on magnetic resonance images of the brain was studied in 351 adults. The foci frequently occurred in the corona radiata and centrum semiovale. The frequency and extent of the foci were closely related to age and to a previous history of cerebrovascular disease. Patients without such a history but with risk factors for cerebrovascular disease tended to have these foci more frequently than those without risk factors.

Brain gray and white matter volume loss accelerates with aging in chronic alcoholics: a quantitative MRI study

Magnetic resonance imaging (MRI) was used to study in vivo the brains of 49 patients with chronic alcoholism, 3 to 4 weeks post-withdrawal, and 43 normal healthy controls, all right-handed male veterans between the ages of 23 and 70 years. MRI scans were analyzed using a semi-automated procedure, which allowed the subcortical regions to be segmented into cerebrospinal fluid (CSF) and brain tissue and the cortical regions to be segmented into CSF, gray matter, and white matter. An age regression model was used to examine the effects of alcohol on brain structure, over and above that expected from the normal aging process. The alcoholics exhibited decreased tissue and increased CSF after correcting for aging. In the cortex, there was significant loss of both gray matter and white matter volume. In this sample of alcoholics, no particular cortical region was preferentially affected or spared. Furthermore, brain tissue volume loss increased with advanced age in the alcoholics. In this group of alcoholics there was no relationship between length of illness and age, i.e., the younger alcoholics had as heavy alcohol use histories as did the older alcoholics. Thus, the increased brain tissue loss with advanced age is interpreted as evidence for age-related increase in brain vulnerability to chronic alcohol abuse.

Periventricular white matter changes and oropharyngeal swallowing in normal individuals

Cranial magnetic resonance imaging (MRI) has revealed patchy periventricular white matter lesions or "unidentified bright objects" (UBOs) in otherwise neurologically intact individuals. Quantitative videofluoroscopic swallowing evaluations and cranial MRI examinations were studied in 49 neurologically normal volunteers (ages 43 to 79 years). Total swallowing duration (TSD) and its subcomponents of oral transit duration (OTD), stage transition duration (STD), and pharyngeal response duration were measured for liquid and semisolid swallows. MRIs were graded from 0, or no UBOs, to 3, or multiple and confluent lesions. The effect of the presence of UBOs on swallowing durational measures and risk factors was analyzed with age differences accounted for statistically (ANCOVA). TSD and OTD for semisolids were significantly differentiated by MRI score (P less than 0.009 and P less than 0.047, respectively). That is, a demonstrable effect was found for an increased number of UBOs on duration of oropharyngeal swallowing in normal individuals.

Serum autoantibodies in patients with Alzheimer's disease and vascular dementia and in nondemented control subjects

BACKGROUND AND PURPOSE

In this study we sought to evaluate the clinical significance of serum autoantibodies to dementing processes.

METHODS

We assessed 40 age-matched subjects: 10 patients with probable Alzheimer's disease, 10 with possible Alzheimer's disease with cerebrovascular disease, 10 with vascular dementia, and 10 nondemented control subjects. Serum from each subject was tested for the presence of antithyroglobulin antibody, thyroid antimicrosomal antibody, gastric anti-parietal cell antibody, anti-smooth muscle antibody, antinuclear antibody, rheumatoid factor, antineuronal antibody, and anticardiolipin antibody. In addition, we investigated the sera of these patients for the presence of an antivascular antibody directed against the vascular basement membrane proteoglycan antigen and for circulating immune complexes.

RESULTS

Autoantibodies were present in 100% of the patients with possible Alzheimer's disease with cerebrovascular disease, 80% of those with vascular dementia, 40% of those with probable Alzheimer's disease, and 30% of the nondemented control subjects. The highest number of autoantibodies was observed in patients with vascular dementia and possible Alzheimer's disease with cerebrovascular disease. Antinuclear antibody was present in 60% of vascular dementia patients and antineuronal antibody in 50% of these patients. However, no individual autoantibody could differentiate Alzheimer's disease from cerebrovascular disorders. Immune complexes were detected in the serum of 20-30% of each patient group. Neither the patient nor the control sera was found to contain antiendothelial antibody.

CONCLUSIONS

Despite the relatively small number of individuals examined in each category, the elevated number of autoantibodies associated with possible Alzheimer's disease with cerebrovascular disease and vascular dementia indicates a possible link between the presence of autoantibodies and cerebrovascular disorders in dementia.