Development of a semi-automated method for quantification of MRI gray and white matter lesions in geriatric subjects

The brain-derived neurotrophic factor VAL66MET polymorphism and cerebral white matter hyperintensities in late-life depression

OBJECTIVE

In animal models, brain-derived neurotrophic factor (BDNF) appears to protect against cerebral ischemia. The authors examined whether the BDNF Val66Met polymorphism, which affects BDNF distribution, was associated with greater volumes of hyperintense lesions as detected on magnetic resonance imaging in a cohort of depressed and nondepressed elders.

DESIGN

Subjects completed cross-sectional assessments, including clinical evaluation and a brain magnetic resonance imaging scan, and provided blood samples for Val66Met genotyping.

SETTING

The study was conducted at a university-based academic hospital.

PARTICIPANTS

Participants included 199 depressed and 113 nondepressed subjects aged 60 years or older.

MEASUREMENT

Hyperintensity lesion volumes were measured using a semiautomated segmentation procedure. Statistical models examined the relationship between genotype and lesion volume while controlling for depression, presence of hypertension, age, and sex.

RESULTS

After controlling for covariates, Met66 allele carriers exhibited significantly greater white matter hyperintensity volumes (F(1,311) = 4.09, p = 0.0442). This effect was independent of a diagnosis of depression or report of hypertension. Genotype was not significantly related to gray matter hyperintensity volume (F(1,311) = 1.14, p = 0.2871).

CONCLUSIONS

The BDNF Met66 allele is associated with greater white matter hyperintensity volumes in older individuals. Further work is needed to determine how this may be associated with other clinically relevant findings in late-life depression.

Lesion identification using unified segmentation-normalisation models and fuzzy clustering

In this paper, we propose a new automated procedure for lesion identification from single images based on the detection of outlier voxels. We demonstrate the utility of this procedure using artificial and real lesions. The scheme rests on two innovations: First, we augment the generative model used for combined segmentation and normalization of images, with an empirical prior for an atypical tissue class, which can be optimised iteratively. Second, we adopt a fuzzy clustering procedure to identify outlier voxels in normalised gray and white matter segments. These two advances suppress misclassification of voxels and restrict lesion identification to gray/white matter lesions respectively. Our analyses show a high sensitivity for detecting and delineating brain lesions with different sizes, locations, and textures. Our approach has important implications for the generation of lesion overlap maps of a given population and the assessment of lesion-deficit mappings. From a clinical perspective, our method should help to compute the total volume of lesion or to trace precisely lesion boundaries that might be pertinent for surgical or diagnostic purposes.

Orbitofrontal cortex volume in late life depression: influence of hyperintense lesions and genetic polymorphisms

BACKGROUND

Orbitofrontal cortex (OFC) volumetric differences have been reported in depression, but in relatively small samples. Factors associated with these differences are not well described. We examined OFC volumes in a large sample of elderly depressed and non-depressed subjects, exploring the relationship between OFC volume, 5HTTLPR genotype, apolipoprotein E (APOE) genotype and hyperintense lesion volume. We hypothesized that smaller OFC volume would be associated with depression, greater hyperintense lesion volume and severity, and APOE epsilon4 or 5HTTLPR short allele carriers.

METHOD

A total of 226 depressed and 144 non-depressed older subjects completed 1.5 T magnetic resonance imaging (MRI) and genotyping. OFC volumes and lesion volumes were measured using standardized methods. Lesion severity was additionally rated using the Coffey rating scale. Differences between groups were compared while controlling for age, sex and total cerebral volume; separate models added lesion measures and genetic polymorphisms.

RESULTS

Depressed subjects exhibited smaller OFC volumes. There was a trend for a negative association between white-matter lesion volume and OFC volume; however, rated white-matter lesion severity was significantly negatively associated with OFC volume. There was no association between gray-matter lesion measures or 5HTTLPR genotype and OFC volume. Contrary to our hypothesis, subjects who were APOE epsilon4 allele positive exhibited larger OFC volumes; in secondary analyses, this finding was limited to the non-depressed group.

CONCLUSIONS

Reduced OFC volumes are seen in depression and associated with greater severity of white-matter lesions. Healthy subjects who are APOE epsilon4 allele positive exhibited larger OFC volumes. This finding should be examined in other populations.

Predicting memory decline in normal elderly: Genetics, MRI, and cognitive reserve

Major predictors of Alzheimer's disease (AD) include apolipoprotein E (APOE)-epsilon4, hippocampal atrophy on magnetic resonance imaging (MRI), and memory dysfunction prior to diagnosis. We examined 159 normal elderly subjects with MRI and the California Verbal Learning Test (CVLT); 84 returned for longitudinal follow-up 5 years later. Analyses at baseline revealed significant variance in hippocampal volume accounted for by cerebral volume and age but not by APOE isoform. However, interactions involving APOE isoform and laterality were observed. As hypothesized, an APOE x time interaction was revealed for CVLT long-delay free recall: APOE-epsilon3/4 subjects had significantly poorer performance than APOE-epsilon3/3 subjects at follow-up. Forward stepwise multiple regression analysis predicting follow-up long-delay free recall selected baseline recall, followed by number of APOE-epsilon4 alleles, followed by left-hippocampal volume. Age and sex did not enter into the model. We conclude that APOE-epsilon4 predicts longitudinal memory decline in healthy controls and that MRI morphometry of hippocampus adds slightly to predictive value.

Texture-based segmentation of diffuse lesions of the brain's white matter

Diffuse lesions of the white matter of the human brain are common pathological findings in magnetic resonance images of elderly subjects. These lesions are typically caused by small vessel diseases (e.g., due to hypertension, diabetes), and related to cognitive decline. Because these lesions are inhomogeneous, unsharp, and faint, but show an intensity pattern that is different from the adjacent healthy tissue, a segmentation based on texture properties is proposed here. This method was successfully applied to a set of 116 image data sets of elderly subjects. Quantitative measures for the lesion load are derived that compare well with results from experts that visually rated lesions on a semiquantitative scale. Texture-based segmentation can be considered as a general method for lesion segmentation, and an outline for adapting this method to similar problems is presented.

Longitudinal magnetic resonance imaging vascular changes, apolipoprotein E genotype, and development of dementia in the neurocognitive outcomes of depression in the elderly study

OBJECTIVE

Several studies suggest that depression is a risk factor for development of dementia in the elderly. In a study of older depressed individuals, the authors examined both neuroimaging and genetic factors in development of dementia. The authors hypothesized that change in subcortical gray matter and white matter hyperintensity volumes would be associated with development of dementia, as would presence of an apolipoprotein E (APOE) epsilon 4 allele.

METHODS

The sample consisted of 161 older depressed subjects without dementia who had magnetic resonance imaging scans at baseline and at two years. Blood samples were also taken to determine APOE genotype. All participants were treated with antidepressants using a guideline-based treatment algorithm. Their cognitive status was evaluated annually. A consensus panel of experts evaluated each case to determine cognitive status and assign a diagnosis.

RESULTS

Twenty subjects became demented over the follow-up period (5.4 years on average). Change in white matter hyperintensity volume was significantly associated with development of dementia, especially among non-Alzheimer dementias. There was a trend for change in subcortical gray matter hyperintensity volume to be associated with incident dementia. APOE genotype was not associated with onset of dementia.

CONCLUSION

Worsening cerebrovascular disease in older depressed adults is associated with cognitive decline and dementia, particularly of the non-Alzheimer disease type. The association of change in white matter lesion volume and incident dementia among depressed elders extends the vascular depression hypothesis of geriatric depression to include cognitive outcomes of depression in the elderly.

Prefrontal white matter lesions and prefrontal task impersistence in depressed and nondepressed elders

Poor task persistence is often observed among depressed individuals, and may be associated with some of the same frontal regions that are involved in depression. The current study explored the association between white-matter lesion volume in prefrontal cortex and noncompletion rates on a complex neurocognitive task among older adults in a treatment study for depression. Older adults in treatment for depression (n=83) and nondepressed (n=47) elders were administered the Stockings of Cambridge subtest (SoC) of the Cambridge Automated Neuropsychological Testing Battery (CANTAB) and completed a brain magnetic resonance imaging scan as part of an ongoing research study. Noncompletion of the SoC occurred in approximately 19% of depressed participants (16/83) and only 2% of nondepressed participants (1/47), which was statistically significant. In multivariate models, failure to complete the SoC was consistently and significantly associated with greater volume of white matter lesions in the anterior-most region of prefrontal cortex, particularly in the left hemisphere, and with greater age. Although SoC completion was not significantly associated with depression severity, noncompletion rates were significantly higher among unremitted individuals and those with comorbid anxiety at study entry. The inability to initiate behavior sufficient to sustain a complex neurocognitive task is a characteristic of geriatric depression which may be associated with integrity of left-prefrontal regions. Future research should investigate whether task impersistence is a construct that generalizes to other neurocognitive tasks, and if it is associated with other adverse outcomes in geriatric depression related to cerebrovascular pathology, such as poor treatment response.

Quantitative morphologic evaluation of magnetic resonance imaging during and after treatment of childhood leukemia

INTRODUCTION

Medical advances over the last several decades, including CNS prophylaxis, have greatly increased survival in children with leukemia. As survival rates have increased, clinicians and scientists have been afforded the opportunity to further develop treatments to improve the quality of life of survivors by minimizing the long-term adverse effects. When evaluating the effect of antileukemia therapy on the developing brain, magnetic resonance (MR) imaging has been the preferred modality because it quantifies morphologic changes objectively and noninvasively.

METHOD AND RESULTS

Computer-aided detection of changes on neuroimages enables us to objectively differentiate leukoencephalopathy from normal maturation of the developing brain. Quantitative tissue segmentation algorithms and relaxometry measures have been used to determine the prevalence, extent, and intensity of white matter changes that occur during therapy. More recently, diffusion tensor imaging has been used to quantify microstructural changes in the integrity of the white matter fiber tracts. MR perfusion imaging can be used to noninvasively monitor vascular changes during therapy. Changes in quantitative MR measures have been associated, to some degree, with changes in neurocognitive function during and after treatment.

CONCLUSION

In this review, we present recent advances in quantitative evaluation of MR imaging and discuss how these methods hold the promise to further elucidate the pathophysiologic effects of treatment for childhood leukemia.

The COMT Val158Met polymorphism and temporal lobe morphometry in healthy adults

We examined the relationship between COMT Val158Met genotype and temporal lobe volumes, including the caudate as a control region. Thirty-one healthy subjects completed 1.5T brain MRI and genotyping. After controlling for demographics, Val158 allele homozygotes exhibited significantly smaller temporal lobe and hippocampal volumes, with a trend for smaller amygdala volumes.

Association of AGTR1 with 18-month treatment outcome in late-life depression

OBJECTIVE

Converging lines of evidence implicate vascular factors in late-life depression, and argue that late-life depression is a distinct entity among the mood disorders. The A1166C polymorphism in the angiotensin II receptor, vascular type 1 (AGTR1) gene has been associated with a range of vascular diseases. This study investigated the association of AGTR1 genotype on 18-month treatment outcome in late-life depression.

METHODS

In a large, prospective cohort study, patients with late-life depression received individualized treatment using a standardized algorithm. The authors genotyped participants at the AGTR1 A1166C single nucleotide polymorphism (SNP) using standardized methodology, then used survival analysis to estimate the impact of A1166C and demographic variables on time to remission during 18 months of follow-up.

RESULTS

The hazard ratio for AGTR1 homozygous C/C status was 0.37. The A1166C SNP showed evidence for genotypic and allelic association in a comparison of remitted and unremitted/censored subjects.

CONCLUSION

Consistent with its association with numerous vascular disorders, AGTR1 is associated with treatment outcome in late-life depression. Further studies are needed to replicate this finding, and to investigate the impact of other genetic markers of vascular disease on late-life depression outcome.

Widespread effects of hyperintense lesions on cerebral white matter structure

OBJECTIVE

Hyperintense lesions are a common finding on neuroimaging and are associated not only with aging, medical illness, and some invasive medical procedures, but also with neurologic and psychiatric morbidity. We hypothesized that hyperintense lesions are associated with alterations in white matter structure beyond the visible lesion boundaries as assessed with diffusion tensor imaging (DTI).

SUBJECTS AND METHODS

Eighty-two neurologically intact older individuals completed brain MRI with DTI. DTI scans were analyzed using regions of interest placed in normal-appearing white matter to measure fractional anisotropy and diffusivity in the white matter of the frontal lobe, the genu of the corpus callosum, and the internal capsule. Hyperintense lesions volumes were measured separately in subcortical gray matter and anterior white matter through a semiautomated segmentation program. The relationship between lesion volumes and DTI measures was examined while controlling for patient age, patient sex, and total cerebral volume.

RESULTS

Greater anterior white matter lesion volumes were associated with higher diffusivity and lower anisotropy in the white matter of the dorsolateral prefrontal cortex and with higher diffusivity of the internal capsule and white matter lateral to the anterior cingulate cortex. Gray matter lesion volumes were associated with higher diffusivity in the genu of the corpus callosum and the internal capsule.

CONCLUSION

Ischemic hyperintense lesions are associated with widespread effects on the structure of the frontal lobe white matter and central white matter structures. This may reflect effects of lesions on neural circuits or identification of white matter changes that have not yet become visible on conventional MRI.

White matter lesion volumes and caudate volumes in late-life depression

BACKGROUND

Decreased caudate volumes and increased white matter lesions (WMLs) are associated both with aging and late-life depression, but the relationship between the two is unclear. We examined the association between WML and caudate volume, hypothesizing there would be a negative association, which would be stronger for WMLs located in anterior regions. We additionally hypothesized that this association would be stronger in depressed subjects.

METHOD

This MRI study included 182 elderly depressed and 64 elderly control subjects. Our imaging analysis procedures divided the brain into anterior and posterior halves. WML volume in each half was calculated, as were left and right caudate volumes. A statistical model incorporating WML volumes, age, total brain volume, diagnosis, and gender was used to examine caudate volumes.

RESULTS

WML volume was negatively associated with total and right caudate volume. This association was stronger for WMLs in the anterior half of the brain. Anterior WML volume was additionally negatively associated with right caudate volume in depressed subjects, but not in controls.

CONCLUSIONS

Using unadjusted levels of significance, WML volume is negatively associated with right caudate volume in both older populations, but with left caudate volume only in depressed individuals. When statistical corrections for multiple comparisons are used, the finding is limited to a negative association between WML volume and right caudate volume, primarily in depressed subjects. This study demonstrates one mechanism by which WMLs may disrupt frontostriatal circuits.

Differences in brain volumes among males and female hormone-therapy users and nonusers

Numerous studies have shown gender differences in the brain volumes of elderly adults. Some evidence shows that higher estrogen levels may be neuroprotective, suggesting that hormone therapy (HT) may in part be responsible for these gender differences; however, few studies have examined the relation between HT and brain volumes. Brain volumes of caudate, putamen, hippocampus, gray matter, white matter, white-matter lesions, and cerebrospinal fluid were measured on magnetic resonance imaging scans. A comprehensive neuropsychological battery was administered. Women were separated into two groups based on HT use, and we used multiple regression analyses to compare these groups with one another and with men. Results of brain-volume measurements showed that HT users had significantly less gray matter and more cerebrospinal fluid than nonusers. Results of the neuropsychological testing showed that HT users performed better on the Shipley Vocabulary Test than males did.

Aging, gender, and the elderly adult brain: an examination of analytical strategies

We sought to examine the relations between age, gender and brain volumes in an elderly population; we also sought to examine ways of measuring these relations. Three sets of analyses were used: correlational analyses, in which correlations between independent variables and brain volumes were calculated without correction for intracranial volume (ICV); covariational analyses, in which ICV was used as a covariate in regression equations; and ratio analyses, in which the dependent variable was the ratio of brain volume to ICV. These analyses yielded similar results, except that (as expected) adjusting for ICV altered estimates of gender differences. Analyses of age showed decreases in left caudate, putamen, and right hippocampus and an increase in CSF, a result generally in accord with previous findings. However, we also found a significant decrease of white-matter volumes and no significant decrease in total gray-matter volumes. Correlational analyses showed that men did not always have larger volumes despite their larger head size; women generally had larger volumes after adjusting for ICV. We found no age-gender interactions.

Lobar distribution of lesion volumes in late-life depression: the Biomedical Informatics Research Network (BIRN)

White matter hyperintense lesions on T2-weighted images are associated with late-life depression. Little work has been carried out examining differences in lesion location between elderly individuals with and without depression. In contrast to previous studies examining total brain white matter lesion volume, this study examined lobar differences in white matter lesion volumes derived from brain magnetic resonance imaging. This study examined 49 subjects with a DSM-IV diagnosis of major depression and 50 comparison subjects without depression. All participants were age 60 years or older. White matter lesion volumes were measured in each hemisphere using a semiautomated segmentation process and localized to lobar regions using a lobar atlas created for this sample using the imaging tools provided by the Biomedical Informatics Research Network (BIRN). The lobar lesion volumes were compared against depression status. After controlling for age and hypertension, subjects with depression exhibited significantly greater total white matter lesion volume in both hemispheres and in both frontal lobes than did control subjects. Although a similar trend was observed in the parietal lobes, the difference did not reach a level of statistical significance. Models of the temporal and occipital lobes were not statistically significant. Older individuals with depression have greater white matter disease than healthy controls, predominantly in the frontal lobes. These changes are thought to disrupt neural circuits involved in mood regulation, thus increasing the risk of developing depression.

Increase in periventricular white matter hyperintensities parallels decline in mental processing speed in a non-demented elderly population

OBJECTIVE

To investigate the influence of deep white matter hyperintensities (DWMH) and periventricular white matter hyperintensities (PVWMH) on progression of cognitive decline in non-demented elderly people.

METHODS

All data come from the nested MRI sub-study of the PROspective Study of Pravastatin in the Elderly at Risk (PROSPER). We performed a 3 year follow up study on 554 subjects of the PROSPER study using both repeated magnetic resonance imaging and cognitive testing. Cognitive decline and its dependency on WMH severity was assessed using linear regression models adjusted for sex, age, education, treatment group, and test version when applicable.

RESULTS

We found that the volume of PVWMH at baseline was longitudinally associated with reduced mental processing speed (p = 0.0075). In addition, we found that the progression in PVWMH volume paralleled the decline in mental processing speed (p = 0.024). In contrast, neither presence nor progression of DWMH was associated with change in performance on any of the cognitive tests.

CONCLUSION

PVWMH should not be considered benign but probably underlie impairment in cognitive processing speed.

Fully automatic segmentation of white matter hyperintensities in MR images of the elderly

The role of quantitative image analysis in large clinical trials is continuously increasing. Several methods are available for performing white matter hyperintensity (WMH) volume quantification. They vary in the amount of the human interaction involved. In this paper, we describe a fully automatic segmentation that was used to quantify WMHs in a large clinical trial on elderly subjects. Our segmentation method combines information from 3 different MR images: proton density (PD), T2-weighted and fluid-attenuated inversion recovery (FLAIR) images; our method uses an established artificial intelligent technique (fuzzy inference system) and does not require extensive computations. The reproducibility of the segmentation was evaluated in 9 patients who underwent scan-rescan with repositioning; an inter-class correlation coefficient (ICC) of 0.91 was obtained. The effect of differences in image resolution was tested in 44 patients, scanned with 6- and 3-mm slice thickness FLAIR images; we obtained an ICC value of 0.99. The accuracy of the segmentation was evaluated on 100 patients for whom manual delineation of WMHs was available; the obtained ICC was 0.98 and the similarity index was 0.75. Besides the fact that the approach demonstrated very high volumetric and spatial agreement with expert delineation, the software did not require more than 2 min per patient (from loading the images to saving the results) on a Pentium-4 processor (512 MB RAM).

Greater MRI lesion volumes in elderly depressed subjects than in control subjects

Hyperintense lesions in both white matter and gray matter on T2-weighted magnetic resonance imaging (MRI) are associated with late-life depression. This large study examined differences in gray and white matter lesion volumes on brain MRI between 253 elderly depressed and 146 control subjects. White matter and gray matter lesion volumes were measured in each hemisphere using a semi-automated segmentation process and compared against depression status. Depressed subjects exhibited significantly greater total white matter (mean 7.22 ml) and gray matter (mean 0.30 ml) lesion volumes in both hemispheres than did control subjects (mean 4.87 ml in white matter and 0.18 ml in gray matter). This difference remained statistically significant even after controlling for confounders such as age, sex, race and reports of hypertension, diabetes and heart disease. Patients with late-life depression have larger white matter lesion and gray matter lesion volumes than do control subjects. Future research should combine similar volumetric techniques with methods of identifying the location of lesions specific to late-life depression.

Improving the segmentation of therapy-induced leukoencephalopathy in children with acute lymphoblastic leukemia using a priori information and a gradient magnitude threshold

Reliably quantifying therapy-induced leukoencephalopathy is a challenging task due to the similarity between its MR properties and those of normal tissues. Multispectral MR images were analyzed for 15 children treated for acute lymphoblastic leukemia. Three different analysis techniques were compared to examine improvements in the segmentation accuracy of leukoencephalopathy versus manual tracings by two experienced observers. The original technique used a white matter mask based on the segmentation of the first serial examination of each patient and no a priori information. The modified techniques combine spatially normalized a priori maps as input and a gradient magnitude threshold. The second technique used a 2D threshold, while the third algorithm utilized a 3D threshold. MR images were segmented with a Kohonen self-organizing map for all three algorithms. Kappa values were compared for the three techniques to each observer and statistically significant improvements were seen between the original and third algorithms (Observer 1: 0.651, 0.744, P = 0.015; Observer 2: 0.603, 0.699, P = 0.024). More accurate and reliable quantification reduces the amount of variance in MR measures and facilitates clinical trials to determine the clinical significance of leukoencephalopathy in this vulnerable population.

Methodology and preliminary results from the neurocognitive outcomes of depression in the elderly study

A methodology is presented for following a cohort of older depressed patients to examine neurocognitive outcomes of depression. A total of 265 depressed individuals and 138 healthy, nondepressed controls age 60 and older who completed at least 1 year of follow-up data underwent periodic clinical evaluation by a geriatric psychiatrist. A subset of 141 patients and 137 controls had neuropsychological testing. A consensus panel of experts reviewed 63 depressed subjects with suspected cognitive impairment. Twenty-seven individuals in the depressed group were assigned diagnoses of dementia, including 11 with Alzheimer's disease, 8 with vascular dementia, and 8 with dementia of undetermined etiology. In addition, 25 individuals had other forms of cognitive impairment, and 11 were considered cognitively normal. Among elderly controls, 2 developed substantial cognitive impairment with clinical diagnoses of dementia. Among the depressed group, the incidence rates for dementia for this age are much higher than would be expected. These results are consistent with prior evidence linking depression and later dementia. Future studies are needed to examine neuroimaging and genetic, clinical, and social predictors of neurocognitive decline in depression.

Clinical characteristics of magnetic resonance imaging-defined subcortical ischemic depression

BACKGROUND

There is a substantial body of research supporting the vascular depression hypothesis of late-life depression. To update this hypothesis so it incorporates recent research, we propose that the term subcortical ischemic vascular depression may be a more accurate representation of the disease process. We sought to investigate this diagnosis as a construct by examining differences between depressed subjects with and without magnetic resonance imaging defined subcortical ischemic vascular depression.

METHODS

This case-control study examined 139 depressed elderly subjects. Demographic data, psychiatric, medical, and family history, depressive symptomatology, and functional impairment were compared between groups dichotomized based on neuroimaging findings.

RESULTS

Seventy-five (54%) of the subjects met neuroimaging criteria for subcortical ischemic vascular depression. Age was most strongly associated with increased prevalence of subcortical ischemic vascular depression. Lassitude and a history of hypertension were also positively associated with the diagnosis; a family history of mental illness and loss of libido were negatively associated with the diagnosis.

CONCLUSIONS

These data support that subcortical ischemic vascular depression may be a specific syndrome from other types of late-life depression. Further research is needed to further characterize this disorder, particularly in regards to cognitive function and treatment implications.

Subcortical lesion severity and orbitofrontal cortex volume in geriatric depression

Previous studies have shown a reduction of orbital frontal cortex volume and an increase in magnetic resonance imaging signal hyperintensities in geriatric depression. We aimed to assess the relationship between subcortical gray- and deep white-matter lesions and orbital frontal cortex volume in elderly depressives and controls. The study included 41 elderly depressed patients and 41 age-matched control subjects. The orbital frontal cortex volume was measured in both hemispheres using a standardized MRI procedure. Signal hyperintensities were rated on (T2)-weighted MRI with qualitative lesion analyses performed according to an established hyperintensity classification system. After controlling for total cerebral hemisphere, age and sex, the geriatric depressed subjects had significant reduction in orbital frontal cortex volume and compared with the control group. Multiple linear regression modeling indicated that reduced orbital frontal cortex volumes were significantly associated with increased subcortical gray-matter lesions. Our study confirmed the reduction of OFC volume in geriatric depressed subjects. We also suggest that subcortical lesions may decrease OFC volume. Further studies are needed to understand how subcortical lesions may be related to OFC volume changes.

Serial MR imaging of volumes of hyperintense white matter lesions in elderly patients: correlation with vascular risk factors

OBJECTIVE

The purpose of the study was to examine change in volume of hyperintense white matter lesions in a cohort of community-dwelling elderly subjects without neuropsychiatric disease. SUBJECTS AND METHODS. One hundred seventeen volunteers underwent brain MR imaging on a 1.5-T scanner. Demographic data and the presence of specific medical illnesses were recorded at the time of the initial scanning. Hyperintense white matter lesion volume was measured using a supervised semiautomated technique that seeded lesions and then created a segmented lesion image. Subjects underwent repeated MR imaging at a mean of 25 months. Mean change in lesion volume and mean percentage of change were determined between the two time points. Logistic regression models were used to examine the differential effects of age, sex, race, and self-reported medical morbidity.

RESULTS

Mean baseline volume of cerebral hyperintense lesions was 4.91 cc, and at 2-year follow-up, it was 6.42 cm(2) (p < 0.0001), for a mean increase of 26.7%. Comparable results were seen in separate analyses of hemispheric hyperintense lesion volumes. Neither sex, race, nor baseline hyperintense lesion volume was significantly associated with an interval increase in lesion volume. Age (p = 0.0117) and presence of diabetes (p = 0.0215) were associated with greater change.

CONCLUSION

Elderly subjects exhibited approximately a 27% increase in hyperintense lesion volume over a 2-year period, a finding influenced by both age and medical comorbidity rates. Because hyperintense lesions can be associated with several neuropsychiatric conditions, further research is needed to determine if interventions designed to slow hyperintense lesion disease progression may improve neuropsychiatric outcomes.

Localization of age-associated white matter hyperintensities in late-life depression

OBJECTIVE

Deep white matter hyperintense lesions are associated with advanced age and late-life depression. The authors examined where age-related cerebral lesions occurred in elderly depressed and healthy control subjects.

METHODS

Eighty-seven depressed subjects and 47 control subjects underwent 1.5 T cranial magnetic resonance imaging (MRI). Utilizing a semiautomated method, a segmented image was created containing only white matter lesions. We created a statistical parametric map (SPM) separately for each subject group that displayed the association between lesions in any voxel and advanced age.

RESULTS

The SPM analysis in depressed subjects demonstrates a significant association between age and lesions found in bilateral, frontal, and left parietal regions. The analysis in control subjects found significant associations only in bilateral parieto-temporal regions, not frontal regions.

CONCLUSIONS

This study demonstrates a different pattern of age-related lesion location between depressed and control subjects. It further supports the theory that frontostriatal disconnection contributes to late-life depression.