Cerebral blood flow correlated with carotid blood flow in neurologically normal elderly with severe white matter lesions

Previous studies of white matter signal hyperintensity (WMSH) on T ₂-weighted MRI (magnetic resonance imaging) have shown it to he related to decreased cerebral blood flow (CBF). However, there have been few studies on the relationship of WMSH and the internal carotid blood flow (CaBF). Doppler ultrasound sonography is widely used for evaluation of CaBF. We analyzed the relationship between CBF, CaBF, and WMSH. The subjects had not suffered cerebral ischemic episodes although they had some risk factors for stroke. They received MRI and were classified into three groups, i.e. mild, moderate, and severe WMSH. The % stenosis of the internal carotid artery (ICA) was measured with angiography. Doppler sonography was used to measure the mean bilateral CaBF. The oxygen-15 steady-state technique and PET (positron emission tomography) were used to measure CBF. There were significant correlations between the % stenosis of ICA and the ipsilateral CaBF and between the % stenosis of ICA and hemispheric CBF. There was a significant relationship between CBF and CaBF in the severe WMSH group, remaining significant after partialling out of the effects of the % stenosis. This indicated that an atherosclerotic change of the cerebral artery occurred in a way that carotid vascular resistence and cerebrovascular resistence were 'proportional'.     

Decreased plasma tryptophan associated with deep white matter lesions in elderly subjects

The aim was to identify potentially treatable riskfactors for cerebral white matter lesions often found on MRI in elderly persons. findings were assessed on 1.0 T MRI of 178 subjects living inthe community and aged 60 years or older. Participants underwent standardised evaluations including standard questionnaires, a physicaland neurological examination, cognitive function tests, electrocardiogram, a complete blood chemistry panel, and plasma aminoacid measurements. Brain MRI infarcts, deep white matter lesions(DWMLs), and periventricular hyperintensities were found in 26%, 43%,and 29% of the 178 participants, respectively. Subjects with DWMLswere significantly older and had a higher frequency of hypertension,higher systolic blood pressure, and more brain infarcts, but lowerplasma concentrations of tryptophan. In the multivariate model, greaterage and lower plasma tryptophan concentrations were independentlyassociated with DWMLs. Tryptophan concentrations were inversely relatedto DWML grading, whereas hypertension and brain infarction were morecommon in subjects with higher extents of DWMLs. The present studysuggests that greater age and lower plasma tryptophanconcentrations were important in producingDWMLs in elderly subjects.

     

Cerebral white matter bundle measurements by magnetic resonance imaging

The width of the anterior whole white matter bundle (AWM), interhemispheric (AWM-TER), and intrahemispheric (AWM-TRA) components at the level of the foramen of Monro on horizontal inversion recovery (IR) magnetic resonance (MR) scans were measured in 32 healthy males. The mean age of subjects were 54.4 +/- 18.8, ranged 25 to 83 years old. MR scans were performed using a 0.5 Tesla superconductive magnet, with inversion time of 400 msec, repetition time of 2.1 sec and echo time of 35 msec. The slice thickness was 10mm. Horizontal maximum internal skull diameter (HISD) at the same level was also measured and normalized values of AWM, AWM-TER, AWM-TRA were calculated by dividing the width of AWM, AWM-TER, AWM-TRA by the width of HISD. When absolute values of each AWM width were compared between right and left sides, there were no differences in AWM and AWM-TER. However, AWM-TRA of the right side was significantly wider than that of the left side (t = 4.28, p less than 0.001). The width of AWM was not correlated with age, but the width of AWM-TER showed a significant decline in the left (r = -0.36, p = 0.04) and non-significant trend to decline in the right side (r = -0.33, p = 0.07). The width of AWM-TRA of the left side was tended to decrease with age. Normalized values of AWM, AWM-TER, AWM-TRA showed a similar results as that of the absolute values. The measurement of the white matter bundle width provide some insights into the connectivity of the brain.(ABSTRACT TRUNCATED AT 250 WORDS)     

Incidental multifocal white matter lesions in pediatric magnetic resonance imaging

This study sought to describe the occurrence and potential significance of white matter abnormalities of unknown cause on pediatric cranial magnetic resonance scans, and to review the literature. We included 16 children in whom white matter abnormalities were incidentally revealed on magnetic resonance scans performed during a 7-year period at a tertiary pediatric medical center. Background data were retrospectively collected from medical files. White matter lesions were classified by size, location, and extent. Indications for imaging included convulsive disorder (n = 5), headache (n = 5), endocrine disorder (n = 4), and others. Patients' abnormalities did not correlate with the locations and patterns of white matter lesions. No changes in lesions were evident over time. Given the absence of evident benefits from repeated imaging studies, we suggest they are not warranted in every patient, and should be tailored according to clinical course. Further investigations of incidental intracranial findings are required in this age group.     

Diffuse white matter lesions associated with herpes simplex encephalitis as observed on magnetic resonance imaging

A 2-year-old boy with herpes simplex encephalitis developed diffuse brain lesions involving the white matter of both cerebral hemispheres. These lesions in the white matter were clearly observed on magnetic resonance imaging (MRI) with the T2-weighted sequence, and were found to have spontaneously disappeared on subsequent MRI performed 7 weeks later. Brain lesions associated with herpes simplex encephalitis in the literature are reviewed and the pathogenesis in the present case is discussed.     

Regional cerebral blood flow in depressed patients with white matter magnetic resonance hyperintensity.

BACKGROUND: Functional neuroimaging studies have consistently demonstrated decreased regional cerebral blood flow (rCBF) or metabolism in the frontal lobe, temporal lobe, or anterior cingulate gyrus of depressed patients. On the other hand, white matter hyperintensity as defined by magnetic resonance imaging (MRI) has been the most consistently replicated finding in structural neuroimaging studies on depression; however, these functional and structural neuroimaging findings of depression have not been well integrated. We aimed to clarify the possible associations of MRI-defined subcortical hyperintensities with rCBF changes in depressed patients. METHODS: Twelve depressed patients with subcortical hyperintensities defined by MRI, 11 depressed patients without MRI hyperintensities, and 25 healthy volunteers underwent 99mTc ECD SPECT. Group comparisons of their rCBF and correlation analysis between MRI hyperintensity and rCBF in patients were performed with a voxel-based analysis using statistical parametric mapping (SPM) software. RESULTS: Depressed patients showed decreased rCBF compared with control subjects in the frontal lobe, temporal lobe, and anterior cingulate gyrus whether subcortical hyperintensity existed or not; however, the patients with MRI hyperintensity showed decreased rCBF in the thalamus, basal ganglia, and brainstem in addition to cortical areas. Further, the score for white matter hyperintensity correlated negatively with rCBF in subcortical brain structures, including the thalamus and right basal ganglia. CONCLUSION: Our study indicates that depressed patients with MRI hyperintensities may have dysfunction in subcortical brain structures in addition to dysfunction in the fronto-temporal cortical structures.     

Cerebral white matter lesions and depressive symptoms in elderly adults

BACKGROUND: There is evidence for a vascular cause of late-life depression. Cerebral white matter lesions are thought to represent vascular abnormalities. White matter lesions have been related to affective disorders and a history of late-onset depression in psychiatric patients. Their relation with mood disturbances in the general population is not known. We investigated the relation between white matter lesions and the presence of depressive symptoms or a history of depression in a population-based study. METHODS: In a sample of 1077 nondemented elderly adults, we assessed the presence and severity of subcortical and periventricular white matter lesions using magnetic resonance imaging, presence of depressive symptoms, and history of depression. Using multiple regression analysis, we examined the relation among white matter lesions, depressive symptoms, and history of depression. RESULTS: Most of the subjects had white matter lesions. Persons with severe white matter lesions (upper quintile) were 3 to 5 times more likely to have depressive symptoms as compared with persons with only mild or no white matter lesions (lowest quintile) (periventricular odds ratio [OR] = 3.3; 95% confidence interval [CI], 1.2-9.5; subcortical OR = 5.4; 95% CI, 1.8-16.5). In addition, persons with severe subcortical but not periventricular white matter lesions were more likely to have had a history of depression with an onset after age 60 years (OR = 3.4; 95% CI, 1.1-10.7) compared with persons with only mild or no white matter lesions. CONCLUSION: The severity of subcortical white matter lesions is related to the presence of depressive symptoms and to a history of late-onset depression.     

Risk factors for white matter changes detected by magnetic resonance imaging in the elderly

We found increased age (p = 0.001) and history or evidence of stroke (p = 0.016) to be significant independent multivariate predictors of the presence and severity of leukoencephalopathy on magnetic resonance imaging brain scans in a mixed population of 35 elderly psychiatric patients and 25 neurologically healthy elderly volunteers. These results suggest that subcortical ischemia, as well as age-related changes that may not be vascular in origin, contribute to the emergence of periventricular and other deep white matter hyperintensities that are commonly seen on the magnetic resonance imaging brain scans of older adults.     

Infantile multiple sclerosis with extensive white matter lesions

A boy developed a right hemiparesis at 13 months of age which disappeared spontaneously at 19 months. Computed tomography and magnetic resonance imaging revealed extensive low-density areas with left-sided predominance in the white matter at age 17 months. The flash visual evoked potential revealed abnormal findings of wave V. At 20 months of age, paraplegia developed; as it receded 3 months later, a left hemiparesis developed. At that time, computed tomography demonstrated a new low-density area in the right centrum semiovale which disappeared at 28 months of age concomitant with the recovery of the left hemiparesis. Overall, he had experienced 3 independent episodes, 2 of which corresponded to each of the lesions depicted by computed tomography and magnetic resonance imaging. Multiple sclerosis was diagnosed at 23 months of age which is earlier than in any previously reported patient. Unlike most typical findings of multiple sclerosis on computed tomography and magnetic resonance imaging studies, our patient demonstrated extensive white matter lesions.     

White matter lesions on magnetic resonance imaging in late-life depression

Objectives: The aims of the present study were to identify the frequency and severity of white matter lesions on the magnetic resonance imaging (MRI) of major depressive disorders and depression caused by cerebrovascular diseases (CVD), to evaluate the relation with cerebrovascular risk factors, and finally to understand an important cause of late‐life depression. Methods: The MRI films of 32 patients over 50 years of age (15 men and 17 women) with major depressive disorders, 25 patients (17 men and eight women) with depression caused by CVD who had scores over 24 on the mini‐mental state examination, and 25 controls (six men and 19 women) were analyzed for white matter lesions according to the modified Fazekas criteria. The cerebrovascular risk factors including hypertension, arteriosclerosis, obesity, smoking, diabetes mellitus, thyroid function abnormalities, EKG abnormality and stroke were also assessed. Results: (i) The frequency of periventricular lesions or deep white matter lesions were significantly higher in patients with depression caused by CVD and major depressive disorders than in controls; (ii) the intracerebral hyperintensities or classical infarctions were prevalent in the frontal cortex (32.0%) and basal ganglia (40.0%); (iii) among cerebrovascular risk factors, stroke (P < 0.005), hypertension (P < 0.025), EKG abnormality (P < 0.005) and smoking (P < 0.05) were significantly prevalent in the patients with depression caused by CVD and major depressive disorders as compared with controls; and (iv) the severity of white matter lesions was significantly associated with the cerebrovascular risk factors (P < 0.005) in patients over 50 years of age with major depressive disorders. Conclusions: The white matter hyperintensities on brain MRI of patients with major depressive disorders over 50 years of age were significantly associated with cerebrovascular risk factors, which suggested a vascular origin of pathogenesis of late‐life depression.     

Cerebral vasomotor reactivity and cerebral white matter lesions in the elderly

OBJECTIVE: The pathogenesis of white matter lesions is still uncertain, but an ischemic-hypoxic cause has been suggested. Cerebral vasomotor reactivity reflects the compensatory dilatory mechanism of the intracerebral arterioles to a vasodilatory stimulus and provides a more sensitive hemodynamic index than the level of resting flow. METHODS: The authors determined the association between vasomotor reactivity and white matter lesions in 73 consecutive individuals from the Rotterdam Scan Study who also participated in the Rotterdam Study, a large population-based prospective follow-up study of individuals > or =55 years old. Vasomotor reactivity was measured by means of CO2-enhanced transcranial Doppler, and in all individuals axial T1*-, T2*-, and proton density (PD)-weighted MRI scans (1.5 T) were obtained. White matter lesions were scored according to location, size, and number by two independent readers. RESULTS: Vasomotor reactivity was inversely associated with the deep subcortical and total periventricular white matter lesions (OR 0.5, 95% CI 0.3 to 1.1; and OR 0.7, 95% CI 0.4 to 1.1, respectively). A strong association was found between impaired vasomotor reactivity and periventricular white matter lesions adjacent to the lateral ventricular wall (OR 0.6, 95% CI 0.4 to 1.0; p = 0.001). No association was found with periventricular white matter lesions near the frontal and occipital horns. CONCLUSIONS: Our data confirm the association between vasomotor reactivity and white matter lesions and support the hypothesis that some white matter lesions may be associated with hemodynamic ischemic injury to the brain.     

Cognition and white matter changes on magnetic resonance imaging in dementia

In a prospective magnetic resonance imaging and cognitive study of 38 demented patients and 15 control subjects, 11 of 27 patients with Alzheimer's disease and 8 of 11 patients with vascular dementia had significant periventricular hyperintensities. Memory and language testing in the early investigation of dementia is useful to distinguish patients with or without periventricular hyperintensities on magnetic resonance imaging. Patients without periventricular hyperintensities are worse on memory and conceptualization tests than patients with periventricular hyperintensities, who tend to be worse on comprehension and attention tests. These differences in cognitive pattern are present between patients with different pathogenesis who are otherwise matched for dementia severity. Language and some nonverbal cognitive deficits correlate with the extent of cortical and ventricular atrophy in Alzheimer's disease.     

Carotid atherosclerosis and cerebral white matter lesions in a population based magnetic resonance imaging study

Cerebral white matter lesions are frequently observed on magnetic resonance imaging of elderly, nondemented persons. There is evidence that white matter lesions are involved in the pathophysiology of cognitive decline and dementia. White matter lesions can be divided into those in the periventricular and those in the subcortical region. Pathological and epidemiological studies suggest that atherosclerosis is involved in the pathogenesis of these lesions. Our study reports on the association between atherosclerosis in the carotid arteries and white matter lesions in a population-based study among 1077 elderly subjects. We randomly sampled 1077 subjects aged between 60–90 years from two prospective population-based studies. All subjects underwent ultrasonography of the carotid artery. In addition, 1.5 T magnetic resonance imaging was performed; white matter lesions in the subcortical and periventricular regions were rated separately. With increasing number of plaques in the carotid artery the severity of periventricular white matter lesions increased (P _trend = 0.03), but not the severity of subcortical white matter lesions (P _trend = 0.19). In addition, an increase in intima media thickness was borderline significantly associated with an increased severity of periventricular white matter lesions (P _trend = 0.09), but not of subcortical white matter lesions (P _trend = 0.68). These findings suggest that partly dissimilar pathogenetic mechanisms are involved in the etiology of periventricular and subcortical white matter lesions. Received: 13 January 1999/Received in revised form: /15 November 1999/Accepted: 17 December 1999     

Pathogenesis of deep white matter medullary infarcts: a diffusion weighted magnetic resonance imaging study

BACKGROUND AND PURPOSE: The pathogenesis of deep white matter medullary (WMM) artery infarcts remains controversial. To address this question, we analysed the stroke patterns of WMM infarcts using diffusion weighted magnetic resonance imaging (DWI) to detect embolic signals and investigate stroke subtypes according to the Trial of Org 10172 in Acute Stroke Treatment (TOAST) classifications. METHODS: We identified WMM infarcts on DWI using templates to determine the subcortical vascular territories. We classified WMM infarcts into those with small artery disease (SAD), large artery disease (LAD), cardioembolism (CE), two or more aetiologies, or undetermined aetiology. Clinical course, risk factors, and cortical spotty lesions were compared. RESULTS: Of the 1420 consecutive patients, 103 (7.3%) met the criteria for WMM infarcts. The stroke subtypes were as follows: 65 (63.1%) patients with LAD, 18 (17.5%) with SAD, 12 (11.7%) with CE, four (3.9%) with two or more aetiologies, three (2.1%) with undetermined aetiology, and one (1.0%) with other determined aetiology. LAD (87.7%) or CE (83.3%) was significantly accompanied by cortical embolic signals as compared to SAD (0%, p<0.001). The LAD infarcts were larger and tended to be chain-like in shape. Ischaemic stroke recurrence was more common in strokes with cortical embolic signals than in those without embolic signals (18.9% v 0%, p = 0.009). CONCLUSIONS: In present study, the most common pathogenesis of WMM infarcts was LAD. Our study indicates that WMM infarcts accompanying cortical embolic signals warrant evaluation of the underlying embolic sources in the large artery or the heart.     

Hypoglycemic encephalopathy with extensive lesions in the cerebral white matter

Here we report an autopsy case of hypoglycemic encephalopathy with prolonged coma. Laboratory data obtained when the patient lapsed into a coma showed that she had a low level of serum glucose (27 mg/dL). Although the level of glucose returned to within the normal range rapidly after glucose infusion, the patient remained in a coma for 22 months. It was presumed that the state of hypoglycemia persisted for about 4 h. There was no evidence of hypotension or hypoxia. Magnetic resonance imaging was performed 3 h after glucose administration; diffusion‐weighted images revealed hyperintensity in the cerebral white matter and in the boundary zone between the middle and posterior cerebral arteries. Post‐mortem examination revealed superficial laminar necrosis throughout the cerebral cortex. Neuronal necrosis was also found in the hippocampus and dentate gyrus, although the CA3 region appeared normal. In addition to these lesions, which are consistent with hypoglycemia‐induced brain damage, the cerebral white matter exhibited severe loss of myelin and axons with reactive astrocytosis and macrophage infiltration. Old infarcts were also present in the bilateral occipital lobes. Since the cerebral blood flow is reported to be decreased during severe hypoglycemia, the present findings suggest that white matter lesions and boundary‐zone infarctions may develop primarily in uncomplicated hypoglycemia.     

Magnetic resonance imaging of white matter lesions in HIV infection.

Previous studies of the frequency of high-signal lesions in human immunodeficiency virus (HIV) infection have had methodological weaknesses regarding lack of control groups, differing machine strengths, and biased subject selection. To obtain a more accurate estimate of prevalence, MRI scans were performed on 243 HIV-positive and HIV-negative homosexual or bisexual men with no history of intravenous drug use. Axial T2-weighted (long TR/TE, spin-echo) MRI scans were rated blindly for presence of focal white matter high-signal lesions. Incidence of hyperintensities was low in all groups, although slightly higher in patients with AIDS, and was not associated with neuropsychological performance. The lower incidence of hyperintensities appears to relate to elimination of methodological problems in previous studies.     

Prevalence of cerebral white matter lesions in elderly people: a population based magnetic resonance imaging study: the Rotterdam Scan Study

OBJECTIVE: White matter lesions are often seen on MR scans of elderly non-demented and demented people. They are attributed to degenerative changes of small vessels and are implicated in the pathogenesis of cognitive decline and dementia. There is evidence that especially periventricular white matter lesions are related to cognitive decline, whereas subcortical white matter lesions may be related to late onset depression. The frequency distribution of subcortical and periventricular white matter lesions according to age and sex reported. METHODS: A total of 1077 subjects aged between 60-90 years were randomly sampled from the general population. All subjects underwent 1.5T MR scanning; white matter lesions were rated separately for the subcortical region and the periventricular region. RESULTS: Of all subjects 8% were completely free of subcortical white matter lesions, 20% had no periventricular white matter lesions, and 5% had no white matter lesions in either of these locations. The proportion with white matter lesions increased with age, similarly for men and women. Women tended to have more subcortical white matter lesions than men (total volume 1.45 ml v 1. 29 ml; p=0.33), mainly caused by marked differences in the frontal white matter lesion volume (0.89 ml v 0.70 ml; p=0.08). Periventricular white matter lesions were also more frequent among women than men (mean grade 2.5 v 2.3; p=0.07). Also severe degrees of subcortical white matter lesions were more common in women than in men (OR 1.1; 95% confidence interval (95% CI) 0.8-1.5) and periventricular white matter lesions (OR 1.2; 95% CI 0.9-1.7), albeit that none of these findings were statistically significant. CONCLUSIONS: The prevalence and the degree of cerebral white matter lesions increased with age. Women tended to have a higher degree of white matter lesions than men. This may underlie the finding of a higher incidence of dementia in women than in men, particularly at later age.