White Matter Hyperintensity on Cranial Magnetic Resonance Imaging

BACKGROUND AND PURPOSE

We have previously reported that several "silent" infarcts found on magnetic resonance imaging (MRI) were a risk factor for stroke. Several recent reports have shown that high white matter grade (WMG) and increasing WMG over time were risk factors for stroke. We tested the hypothesis that high WMG > or =2 was a predictor of risk for stroke, independent of other risk factors.

METHODS

We examined the extent of white matter hyperintensity on cranial MRI of 3293 participants from the Cardiovascular Health Study (CHS). The degree of white matter hyperintensity was graded from least severe (grade=0) to most severe (grade=9). Participants were followed-up for an average of 7 years for the occurrence of a stroke. Clinical stroke diagnoses were based on hospital records reviewed by an adjudication committee expert in stroke diagnosis. During this period, 278 strokes occurred. Results The relative risk of stroke increased significantly as the WMG increased. The risk of stroke was 2.8% per year for participants with high WMG (grades > or =5), compared with only 0.6% for participants with grades 0 to 1.Conclusions The risk of stroke with high WMG is independent of traditional stroke risk factors and persists when controlling for MRI infarcts, another subclinical imaging marker of cerebrovascular disease. Assessment of white matter disease may be valuable in assessing future risk of stroke.

Is the spatial distribution of brain lesions associated with closed-head injury in children predictive of subsequent development of posttraumatic stress disorder?

PURPOSE

To determine whether there is an association between the spatial distributions of lesions detected at magnetic resonance (MR) imaging of the brain in children, adolescents, and young adults after closed-head injury (CHI) and development of the reexperiencing symptoms of posttraumatic stress disorder (PTSD).

MATERIALS AND METHODS

Data obtained in 94 subjects without a history of PTSD as determined by parental interview were analyzed. MR images were obtained 3 months after CHI. Lesions were manually delineated and registered to the Talairach coordinate system. Mann-Whitney analysis of lesion distribution and PTSD status at 1 year (again, as determined by parental interview) was performed, consisting of an analysis of lesion distribution versus the major symptoms of PTSD: reexperiencing, hyperarousal, and avoidance.

RESULTS

Of the 94 subjects, 41 met the PTSD reexperiencing criterion and nine met all three PTSD criteria. Subjects who met the reexperiencing criterion had fewer lesions in limbic system structures (eg, the cingulum) on the right than did subjects who did not meet this criterion (Mann-Whitney, P =.003).

CONCLUSION

Lesions induced by CHI in the limbic system on the right may inhibit subsequent manifestation of PTSD reexperiencing symptoms in children, adolescents, and young adults.

Morphometric analysis of cortical sulci using parametric ribbons: a study of the central sulcus

Interhemispheric and gender differences of the central sulcus were examined via a parametric ribbon approach. The central sulcus was found to be deeper and larger in the right nondominant hemisphere than in the left dominant hemisphere, both in males and in females. Based on its pattern, that asymmetry could be attributed to increased connectivity between motor and somatosensory cortex, facilitating fine movement, which could constrain the in-depth growth of the central sulcus. Position asymmetries were also found, which might be explained by a relative larger parietal association cortex in men but not in women.

Cognitive correlates of human brain aging: a quantitative magnetic resonance imaging investigation

The relations between age-related changes in brain structure and neuropsychological test performance in 320 elderly nonclinical volunteers (ages 66-90) were examined by using quantitative MRI data and measures of attention, information processing speed, language, memory, and visuospatial ability. Final path analyses revealed significant brain-behavior relationships for two of the six cognitive measures: the Trail Making Test part B and visual delayed memory. Poorer performance on Trails B was associated with smaller cerebral hemisphere volumes and larger volumes of peripheral CSF, lateral ventricles, and third ventricle. Poorer recall on visual delayed memory was associated with larger volumes of the lateral ventricles and third ventricle. The findings demonstrate a relationship between age-related changes in brain structure and an age-related decline in attention, psychomotor speed, and visual delayed memory. The neurobiological basis for this relationship requires further investigation.

Quantitative proton MR spectroscopic imaging in acute disseminated encephalomyelitis

Serial MR imaging and quantitative proton MR spectroscopic imaging (MRSI) findings of a 4-year-old boy with acute disseminated encephalomyelitis (ADEM) are reported. Over a 2-month period characterized by an initial illness and two relapses, each with full recovery, MR imaging exhibited the appearance and disappearance of multifocal lesions throughout the CNS that correlated only partly with the neurologic impairment. During one relapse, MRSI revealed low levels of N-acetylaspartate (NAA) within the regions of prolonged T2 signal intensity. All other metabolites were normal. At follow-up, the MR imaging and MRSI abnormalities had fully resolved. MRSI might play an important role in the diagnosis of ADEM, as well as in the elucidation of underlying pathophysiologic processes in this poorly defined disorder of children. This case demonstrates that reduced levels of NAA are not always associated with neuronal loss, irreversible tissue damage, or poor neurologic outcome.

Association between blood pressure level and the risk of myocardial infarction, stroke, and total mortality: the cardiovascular health study

BACKGROUND

Recent reports have drawn attention to the importance of pulse pressure as a predictor of cardiovascular events. Pulse pressure is used neither by clinicians nor by guidelines to define treatable levels of blood pressure.

METHODS

In the Cardiovascular Health Study, 5888 adults 65 years and older were recruited from 4 US centers. At baseline in 1989-1990, participants underwent an extensive examination, and all subsequent cardiovascular events were ascertained and classified.

RESULTS

At baseline, 1961 men and 2941 women were at risk for an incident myocardial infarction or stroke. During follow-up that averaged 6.7 years, 572 subjects had a coronary event, 385 had a stroke, and 896 died. After adjustment for potential confounders, systolic blood pressure (SBP), diastolic blood pressure (DBP), and pulse pressure were directly associated with the risk of incident myocardial infarction and stroke. Only SBP was associated with total mortality. Importantly, SBP was a better predictor of cardiovascular events than DBP or pulse pressure. In the adjusted model for myocardial infarction, a 1-SD change in SBP, DBP, and pulse pressure was associated with hazard ratios (95% confidence intervals) of 1.24 (1.15-1.35), 1.13 (1.04-1.22), and 1.21 (1.12-1.31), respectively; and adding pulse pressure or DBP to the model did not improve the fit. For stroke, the hazard ratios (95% confidence intervals) were 1.34 (1.21-1.47) with SBP, 1.29 (1.17-1.42) with DBP, and 1.21 (1.10-1.34) with pulse pressure. The association between blood pressure level and cardiovascular disease risk was generally linear; specifically, there was no evidence of a J-shaped relationship. In those with treated hypertension, the hazard ratios for the association of SBP with the risks for myocardial infarction and stroke were less pronounced than in those without treated hypertension.

CONCLUSION

In this population-based study of older adults, although all measures of blood pressure were strongly and directly related to the risk of coronary and cerebrovascular events, SBP was the best single predictor of cardiovascular events.

Multiple brain atlas database and atlas-based neuroimaging system

For the purpose of developing multiple, complementary, fully labeled electronic brain atlases and an atlas-based neuroimaging system for analysis, quantification, and real-time manipulation of cerebral structures in two and three dimensions, we have digitized, enhanced, segmented, and labeled the following print brain atlases: Co-Planar Stereotaxic Atlas of the Human Brain by Talairach and Tournoux, Atlas for Stereotaxy of the Human Brain by Schaltenbrand and Wahren, Referentially Oriented Cerebral MRI Anatomy by Talairach and Tournoux, and Atlas of the Cerebral Sulci by Ono, Kubik, and Abernathey. Three-dimensional extensions of these atlases have been developed as well. All two- and three-dimensional atlases are mutually preregistered and may be interactively registered with an actual patient's data. An atlas-based neuroimaging system has been developed that provides support for reformatting, registration, visualization, navigation, image processing, and quantification of clinical data. The anatomical index contains about 1,000 structures and over 400 sulcal patterns. Several new applications of the brain atlas database also have been developed, supported by various technologies such as virtual reality, the Internet, and electronic publishing. Fusion of information from multiple atlases assists the user in comprehensively understanding brain structures and identifying and quantifying anatomical regions in clinical data. The multiple brain atlas database and atlas-based neuroimaging system have substantial potential impact in stereotactic neurosurgery and radiotherapy by assisting in visualization and real-time manipulation in three dimensions of anatomical structures, in quantitative neuroradiology by allowing interactive analysis of clinical data, in three-dimensional neuroeducation, and in brain function studies.

One-year age changes in MRI brain volumes in older adults

Longitudinal studies indicate that declines in cognition and memory accelerate after age 70 years. The neuroanatomic and neurophysiologic underpinnings of cognitive change are unclear, as there is little information on longitudinal brain changes. We are conducting a longitudinal neuroimaging study of nondemented older participants in the Baltimore Longitudinal Study of Aging. This report focuses on age and sex differences in brain structure measured by magnetic resonance imaging during the first two annual evaluations. Cross-sectional results from 116 participants aged 59-85 years reveal significantly larger ventricular volumes and smaller gray and white matter volumes in older compared with younger participants and in men compared with women. Regional brain volumes show that the effects of age and sex are not uniform across brain regions. Age differences are greatest for the parietal region. Sex differences tend to be larger for frontal and temporal than parietal and occipital regions. Longitudinal analysis demonstrates an increase of 1526 mm(3) in ventricular volume over 1 year, but no detectable change in total or regional brain volumes. Definition of the pattern and rate of longitudinal brain changes will facilitate the detection of pathological brain changes, which may be predictors of dementia.

CPT-EIA assays for the detection of vancomycin resistant vanA and vanB genes in enterococci

Cycling Probe Technology (CPT) was combined with a colorimetric enzyme-immuno assay (EIA) to develop two assays for the detection of vanA and vanB genes in vancomycin resistant enterococci (VRE). The CPT-EIA assay employs a gene-specific fluorescein labeled DNA-RNA-DNA probe that gets cleaved within the probe : target duplex. The cleaved DNA probe fragments dissociate from the target, making it available for further cycling. Following the separation of cleaved probe fragments, anti-fluorescein-horseradish peroxidase antibodies are used for the detection of uncleaved probes. The two CPT-EIA assays were used to screen a collection of 440 clinical isolates (Modrusan et al., 1999). All of the 154 VanA and 131 VanB isolates were correctly identified in the vanA and vanB CPT-EIA, respectively. The VanA and VanB isolates were differentiated from vancomycin sensitive enterococci (VSE) and also from the VanC isolates. In addition, an accurate VRE detection in the CPT-EIA assay was shown with cultures grown on eight different media.

Neuroimaging variables related to development of Secondary Attention Deficit Hyperactivity Disorder after closed head injury in children and adolescents

OBJECTIVE

To characterize children who develop Secondary Attention Deficit Hyperactivity Disorder (S-ADHD) after severe and moderate closed head injury (CHI) according to neuroimaging variables.

METHOD

Ninety-nine children from 4-19 years who suffered severe and moderate CHI were prospectively followed for a year after injury. Premorbid psychiatric status was determined by administration to the parent of a structured psychiatric interview. This interview was readministered 1 year after injury to determine the presence of post-closed head injury S-ADHD. An MRI was performed 3 months after injury to define lesion locations and volumes.

RESULTS

A set of multiple logistic regression models determined that the odds of developing S-ADHD were 3.64 times higher among children with thalamus injury, and 3.15 times higher among children with basal ganglia injury. There was no significant difference in lesion volumes in any of the locations of interest between the group who developed S-ADHD and the group who did not develop S-ADHD.

CONCLUSION

The data support an association between S-ADHD and injury in either or both the thalamus and basal ganglia, but they do not definitively demonstrate whether injury in either structure has an effect on S-ADHD in the absence of injury in the other.

Is the spatial distribution of brain lesions associated with closed-head injury predictive of subsequent development of attention-deficit/hyperactivity disorder? Analysis with brain-image database

PURPOSE

To determine whether there is an association between the spatial distribution of lesions detected at magnetic resonance (MR) imaging of the brain in children after closed-head injury and the development of secondary attention-deficit/hyperactivity disorder (ADHD).

MATERIALS AND METHODS

Data obtained from 76 children without prior history of ADHD were analyzed. MR images were obtained 3 months after closed-head injury. After manual delineation of lesions, images were registered to the Talairach coordinate system. For each subject, registered images and secondary ADHD status were integrated into a brain-image database, which contains depiction (visualization) and statistical analysis software. Using this database, we assessed visually the spatial distributions of lesions and performed statistical analysis of image and clinical variables.

RESULTS

Of the 76 children, 15 developed secondary ADHD. Depiction of the data suggested that children who developed secondary ADHD had more lesions in the right putamen than children who did not develop secondary ADHD; this impression was confirmed statistically. After Bonferroni correction, we could not demonstrate significant differences between secondary ADHD status and lesion burdens for the right caudate nucleus or the right globus pallidus.

CONCLUSION

Closed-head injury-induced lesions in the right putamen in children are associated with subsequent development of secondary ADHD. Depiction software is useful in guiding statistical analysis of image data.

Neuroanatomic and functional correlates of depressed mood: the Cardiovascular Health Study

Although a number of studies suggest an association between stroke and depression, few have examined the relation between magnetic resonance imaging (MRI)-identified lesions and depression among community-dwelling older adults. This cross-sectional study sought to assess the association between MRI infarcts in the basal ganglia and non-basal-ganglia areas, potential functional consequences of these lesions, and depressive symptomatology in 3,371 US men and women aged 65 years or older who participated in the Cardiovascular Health Study between 1992 and 1994. By using multiple linear regression models, the authors found that after adjustment for age, gender, and stroke history, Center for Epidemiologic Studies Depression Scale scores were independently associated with non-basal-ganglia lesions (p = 0.04) but were not independently associated with basal ganglia lesions (p = 0.11). When measures of physical disability and cognitive impairment were added to the models, these measures displaced MRI-identified infarcts in their association with depressive symptoms. In additional models, hemispheric location and size of the basal ganglia lesion were found to have no relation to depression levels. These results suggest that the functional consequences of cerebrovascular disease may be the causal pathway by which basal ganglia and non-basal-ganglia lesions are associated with depressive symptomatology.