Renal artery stenosis evaluation in chronic kidney disease patients: nonenhanced time-spatial labeling inversion-pulse three-dimensional MR angiography with regulated breathing versus DSA.

PURPOSE: To evaluate the diagnostic performance of nonenhanced magnetic resonance (MR) angiographic flow-in technique with three-dimensional balanced steady-state free precession (SSFP) (flow-in balanced SSFP), compared with digital subtraction angiography (DSA) as reference standard, for assessment of renal artery stenosis (RAS) in chronic kidney disease (CKD) patients. MATERIALS AND METHODS: Institutional review board approval and written informed consent were obtained for this prospective HIPAA-compliant study. Twenty-three patients, 13 men (mean age, 67.6 years ± 8.1 [standard deviation]; age range, 58-86 years) and 10 women (mean age 73.1 years ± 12.4; age range, 49-89 years), were evaluated with flow-in balanced SSFP and DSA. Coronal and axial flow-in balanced SSFP images were obtained with 1.5-T system, with regulated breathing (recorded voice instruction). The quality of flow-in balanced SSFP images was visually evaluated; the degree of stenosis was compared between flow-in balanced SSFP source images and DSA images by using the Wilcoxon signed-rank test. Correlation between images from both modalities was calculated as the Spearman rank-order correlation coefficient; bias was examined with Bland-Altman plots. RESULTS: Diagnostic images were obtained in all patients. Flow-in balanced SSFP image quality was good in 87% (20 of 23) and moderate in 13% (three of 23) of patients. Forty-five renal arteries were included in the statistical analysis. Of 36 stenoses detected with flow-in balanced SSFP, 28 were relevant (degree of stenosis, ≥ 50%). The stenosis measurements of flow-in balanced SSFP were highly correlated (ρ = 0.91, P < .001) with those of DSA. The Bland-Altman plot showed a slight overestimation of the degree of stenosis (mean bias, 2.33% ± 11.95). The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of flow-in balanced SSFP relative to DSA for the diagnosis of a stenosis of 50% or greater were 93% (26 of 28), 88% (15 of 17), 93% (26 of 28), 88% (15 of 17), and 91% (41 of 45), respectively. CONCLUSION: Flow-in balanced SSFP with regulated breathing is an appropriate nonenhanced MR angiographic technique for RAS assessment in CKD patients. SUPPLEMENTAL MATERIAL: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.11101422/-/DC1.

Noncontrast-enhanced peripheral MRA: technical optimization of flow-spoiled fresh blood imaging for screening peripheral arterial diseases.

Flow-spoiled fresh blood imaging, a noncontrast peripheral MR angiography technique, allows the depiction of the entire tree of peripheral arteries by utilizing the signal difference between systolic- and diastolic-triggered data. The image quality of the technique relies on selecting the right triggering delay times and flow-dependent read-out spoiler gradient pulses. ECG triggering delays were verified using manual subtraction and automated software. The read-out spoiler gradients pulses were optimized on volunteers before utilizing the flow-spoiled fresh blood imaging technique to screen for peripheral arterial disease. Thirteen consecutive patients with suspected peripheral arterial disease underwent both flow-spoiled fresh blood imaging and 16-detector-row computed tomography angiography examinations. A total of 23 segments were evaluated in the arterial vascular system. Using computed tomography angiography as the reference standard, 56 diseased segments were detected with 22 nonsignificant stenoses (<50%) and 34 significant stenoses, 15 of which were totally occluded. Flow-spoiled fresh blood imaging had a sensitivity of 97%, a specificity of 96%, an accuracy of 96%, a positive predictive value of 88%, and a negative predictive value of 99%. With such a high negative predictive value, flow-spoiled fresh blood imaging has the potential to become the safest noninvasive screening tool for peripheral arterial disease, especially for patients with impaired renal function.

Ventricular dilation: association with gait and cognition.

OBJECTIVE: Normal pressure hydrocephalus is characterized by gait impairment, cognitive impairment, and urinary incontinence, and is associated with disproportionate ventricular dilation. Here we report the distribution of ventricular volume relative to sulcal cerebrospinal fluid (CSF) volume, and the association of increasing ventricular volume relative to sulcal CSF volume with a cluster of gait impairment, cognitive impairment, and urinary incontinence in a stroke-free cohort of elderly persons from the general population. METHODS: Data are based on 858 persons (35.4% men; age range, 66-92 years) who participated in the Age, Gene/Environment Susceptibility-Reykjavik Study. Gait was evaluated with an assessment of gait speed. Composite scores representing speed of processing, memory, and executive function were constructed from a neuropsychological battery. Bladder function was assessed with a questionnaire. Magnetic resonance brain imaging was followed by semiautomated segmentation of intracranial CSF volume. White matter hyperintensity (WMH) volume was assessed with a semiquantitative scale. For the analysis of ventricular dilation relative to the sulcal spaces, ventricular volume was divided by sulcal CSF volume (VV/SV). RESULTS: Disproportion between ventricular and sulcal CSF volume, defined as the highest quartile of the VV/SV z score, was associated with gait impairment (odds ratio [OR], 1.9; 95% confidence interval [CI], 1.1-3.3) and cognitive impairment (OR, 1.8; 95% CI, 1.1-3.0). We did not find an association between the VV/SV z score and bladder dysfunction. INTERPRETATION: The prevalence and severity of gait impairment and cognitive impairment increases with ventricular dilation in persons without stroke from the general population, independent of WMH volume.

Frontal lobe structure and executive function in migraine patients.

Neuroimaging studies have identified frontal lobe brain abnormalities in migraineurs. Neuropsychological investigations highlighted frontal lobe related cognitive impairments in migraineurs, including working memory and executive function deficits. The relationship between brain anatomy and cognitive function in migraine, however, is unclear. The aim of this study was to simultaneously investigated cortex structure and executive function (EF) in patients with migraine and control subjects. Thus, we assessed grey matter (GM) density in 25 adult patients with migraine, compared to age and sex-matched control subjects, using magnetic resonance imaging (MRI) and voxel-based-morphometry (VBM), and we measured EF in the same population, employing three EF tasks of the Maudsley attention and response suppression (MARS) battery. Migraineurs, compared to control subjects, showed decreased frontal and parietal lobe GM density and slower response time to task set-shifting and, the delayed response time correlated significantly with reduced GM density of the frontal lobes in migraineurs. Frontal and parietal lobe abnormalities in migraineurs could be an underlying cause of significantly slower response time during cognitive set-shifting.

Risk factors for cerebral microbleeds in the elderly.

BACKGROUND: To define the cardiovascular risk factors for cerebral microbleeds and to investigate the relationship between microbleeds on the one hand, and the volume of age-related white matter hyperintensities (WMH) and atrophy on the other in an elderly population. METHODS: Four hundred and thirty-nine elderly subjects (age range: 72-85; mean: 77) suffering from vascular disease or at high risk for developing this condition were included in this study. For each subject the number and localization of the microbleeds was recorded. RESULTS: The prevalence of microbleeds in this study was 24%. We found age and a history of hypertension to be risk factors for microbleeds. After regional subdivision systolic blood pressure was found to be a risk factor for microbleeds located in the basal ganglia. A history of hypertension was more prevalent in patients with corticosubcortical and basal ganglia microbleeds. Magnetic resonance imaging risk factors associated with one or more microbleeds were total WMH volume, subcortical WMH volume, and periventricular WMH volume. Total WMH volume and periventricular WMH volume were risk factors for corticosubcortical microbleeds and basal ganglia microbleeds. CONCLUSION: A high prevalence of microbleeds was found in a population of patients suffering from vascular disease or at high risk for developing this condition. Age, hypertension and WMH were the most important risk factors for microbleeds, especially when located in the corticosubcortial junction or in the basal ganglia.

Attack frequency and disease duration as indicators for brain damage in migraine.

OBJECTIVE: The aim of this study was to pinpoint predilection sites of brain damage in migraine by quantitatively identifying morphometric and diffusion differences in migraineurs, compared with control subjects, and to assess whether migraine attack frequency and attack history are indicators for brain abnormalities in migraineurs. BACKGROUND: Previous clinical neuroimaging investigations introduced the concept of migraine as a progressive brain disease. They reported an increased risk of white matter hyperintensities (WMH) with increasing attack frequency in migraineurs. METHODS: We investigated 28 patients with migraine, using high-resolution T1- and diffusion-weighted magnetic resonance imaging and optimized voxel-based morphometry to localize gray and WM density, and fractional anisotropy and apparent diffusion coefficient differences. RESULTS: We identified predilection sites of brain abnormalities in migraineurs in the frontal lobes, brainstem, and the cerebellum, and we show that both attack frequency and disease duration are indicators for brain damage in migraine. CONCLUSION: Our findings report an unbiased quantitative whole brain assessment of morphological abnormalities in migraine. This might help to identify indicators for migraine as a possibly progressive brain disease. In order to reveal the causes and consequences of brain damage in migraine, further neuroimaging studies have to investigate quantitative brain changes in a longitudinal design.

Autonomous virtual mobile robot for three-dimensional medical image exploration: application to micro-CT cochlear images.

OBJECTIVE: In this paper, we present an autonomous virtual mobile robot (AVMR) for three-dimensional (3D) exploration of unknown tubular-like structures in 3D images. METHODS AND MATERIALS: The trajectory planning for 3D central navigation is achieved by combining two neuro-fuzzy controllers, and is based on 3D sensory information; a Hough transform is used to locally fit a cylinder during the exploration, estimating the local radius of the tube. Nonholonomic constraints are applied to assure a smooth, continuous and unique final path. When applied to 3D medical images, the AVMR operates as a virtual endoscope, directly providing anatomical measurements of the organ. After a thorough validation on challenging synthetic environments, we applied our method to eight micro-CT datasets of cochleae. RESULTS: Validation on synthetic environments proved the robustness of our method, and highlighted key parameters for the design of the AVMR. When applied to the micro-CT datasets, the AVMR automatically estimated length and radius of the cochleae: results were compared to manual delineations, proving the accuracy of our approach. CONCLUSIONS: The AVMR presents several advantages when used as a virtual endoscope: the nonholonomic constraint guarantees a unique and smooth central path, which can be reliably used both for qualitative and quantitative investigation of 3D medical datasets. Results on the micro-CT cochleae are a significant step towards the validation of more clinical computed tomography (CT) studies.

GAMEs: growing and adaptive meshes for fully automatic shape modeling and analysis.

This paper presents a new framework for shape modeling and analysis, rooted in the pattern recognition theory and based on artificial neural networks. Growing and adaptive meshes (GAMEs) are introduced: GAMEs combine the self-organizing networks which grow when require (SONGWR) algorithm and the Kohonen's self-organizing maps (SOMs) in order to build a mesh representation of a given shape and adapt it to instances of similar shapes. The modeling of a surface is seen as an unsupervised clustering problem, and tackled by using SONGWR (topology-learning phase). The point correspondence between point distribution models is granted by adapting the original model to other instances: the adaptation is seen as a classification task and performed accordingly to SOMs (topology-preserving phase). We thoroughly evaluated our method on challenging synthetic datasets, with different levels of noise and shape variations. Finally, we describe its application to the analysis of a challenging medical dataset. Our method proved to be reproducible, robust to noise, and capable of capturing real variations within and between groups of shapes.

The effect of corticosteroid medication on quantitative MR parameters of the brain.

BACKGROUND AND PURPOSE: Quantitative MR imaging techniques such as magnetization transfer imaging (MTI), diffusion-weighted imaging (DWI), and MR spectroscopy are promising diagnostic tools for use with patients with diffuse brain diseases such as neuropsychiatric systemic lupus erythematosus (NPSLE). Such patients are often on corticosteroid (CS) treatment. Presently, it is unknown whether CSs per se influence quantitative MR imaging measurements. The aim of this study was to evaluate the effect of low-dose oral CSs on MTI, DWI, and MR spectroscopy parameters of the brain. METHODS: Twenty-seven rheumatoid arthritis (RA) patients with and without CS medication and 15 healthy controls were subjected to conventional MR imaging, whole-brain MTI and DWI, and single-voxel MR spectroscopy. Oral CSs were used by 13 of the RA patients. Univariate analyses with age as a covariate were performed on MTI, DWI, and MR spectroscopy parameters between RA patients with and without CSs and healthy controls. Pearson correlations were calculated between all imaging parameters and duration of disease, duration of CS use, and CS dosage. RESULTS: No significant differences between the groups of subjects or significant correlations with clinical parameters were found for MTI, DWI and MR spectroscopy parameters. CONCLUSION: In this study, we found no evidence for an effect of low-dose oral CSs on whole-brain MTI and DWI histogram parameters and single-voxel MR spectroscopy measurements of the brain. The results of this study demonstrate that it is unlikely that MTI, DWI, and MR spectroscopy parameters reported in NPSLE studies are confounded by low-dose oral CS.

Memory complaints in patients with normal cognition are associated with smaller hippocampal volumes.

We aimed to investigate volumetry of the medial temporal lobe in patients with subjective memory complaints without any cognitive impairment. This study included 20 patients with subjective memory complaints and normal cognitive function and 28 controls without memory complaints. Volumes of the hippocampus and parahippocampal gyrus (PHG) were measured using coronal T1-weighted MR images. Cognitive functions were assessed using the Cambridge Cognitive Examination. Depressive symptoms were assessed using the Geriatric Depression Scale. Differences between groups were analysed using t-tests. Patients with subjective memory complaints had a higher education and more depressive symptoms than controls ( p < 0.01). Moreover, they had smaller left hippocampal volumes than controls ( p < 0.01). There were no differences between groups in the volume of the right hippocampus or PHG. There was a moderate association between the volume of left hippocampus and left PHG and memory-score (r = 0.32, p = 0.03; r = 0.34, p = 0.02). We concluded that memory complaints in patients without any cognitive impairment were associated with smaller left hippocampal volumes and more depressive symptoms. These preliminary results suggest that memory complaints may reflect minimal brain deficits associated with impending dementia, depression or a combination of both disorders.

Associations between magnetic resonance imaging measures and neuropsychological impairment in early and late onset alzheimer's disease.

AIM: To assess the associations of global atrophy and white matter hyperintensities (WMH) with neuropsychological function in early and late onset Alzheimer's disease (AD). METHODS: We included 107 patients with sporadic AD (21 early onset and 86 late onset) from our memory clinic. Tests for (working) memory, language, executive function, mental speed, and attention were administered. Global atrophy and global and lobar WMH were measured using 1 Tesla MRI. Linear regression analyses with terms for MRI measures, neuropsychological test results, age, gender, education, and the interaction between separate brain measures and age of onset were performed. RESULTS: Global atrophy was associated with more severely impaired global cognition, working memory, mental speed, and executive function (p < 0.05). Significant interactions between global atrophy and age at onset showed that these associations were mostly attributable to patients with early onset AD. By contrast, an association between global atrophy and memory was found, which was specifically attributable to late onset AD patients. No associations between global WMH and cognitive function were found. Subsequently we analyzed regional WMH and found that temporal WMH was associated with impaired memory, and frontal WMH was associated with slower mental speed. CONCLUSION: Cortical atrophy, a key feature of AD, is linked to a wide range of cognitive functions, specifically in early onset AD patients. For WMH, there were no interactions with age at onset, but we found specific associations between temporal WMH and memory and frontal WMH and mental speed.

Associations between total cerebral blood flow and age related changes of the brain.

BACKGROUND AND PURPOSE: Although total cerebral blood flow (tCBF) is known to be related to age, less is known regarding the associations between tCBF and the morphologic changes of the brain accompanying cerebral aging. The purpose of this study was to investigate whether total cerebral blood flow (tCBF) is related to white matter hyperintensity (WMH) volume and/or cerebral atrophy. Furthermore, we investigate whether tCBF should be expressed in mL/min, as was done in all previous MR studies, or in mL/100 mL/min, which yielded good results in precious SPECT, PET and perfusion MRI studies investigating regional cerebral blood flow. MATERIALS AND METHODS: Patients were included from the nested MRI sub-study of the PROSPER study. Dual fast spin echo and FLAIR images were obtained in all patients. In addition, single slice phase contrast MR angiography was used for flow measurements in the internal carotids and vertebral arteries. tCBF was expressed in both mL/min and mL/100 mL/min. RESULTS: We found a significant correlation between tCBF in mL/min and both age (r = -.124; p = p

Anatomic considerations of cochlear morphology and its implications for insertion trauma in cochlear implant surgery.

HYPOTHESIS: The goal of this study is to analyze the 3-dimensional anatomy of the cochlear spiral and to investigate the consequences of its course to insertion trauma during cochlear implantation. BACKGROUND: Insertion trauma in cochlear implant surgery is a feared surgical risk, potentially causing neural degeneration and altered performance of the implant. In literature, insertion trauma is reported to occur at specific locations. This has been ascribed to surgical technique and electrode design in relation to the size of the scala tympani. This study investigates whether there is an underlying anatomic substrate serving as a potential source for insertion trauma at these specific locations. METHODS: The 3-dimensional path of the cochlear spiral of 8 human temporal bones was determined by segmentation, skeletonization, distance mapping, and wave propagation technique applied on microcomputer tomography images. Potential pressure points along this path were estimated with linear regression. RESULTS: The cochlear lumen shows a noncontinuous spiraling path leading to potential pressure points during cochlear implantation at the basilar membrane in the region of 180 to 225 (12-14 mm) and 725 degrees (22-26 mm) and at the floor of the scala tympani around 0 to 90, 225 to 270, and 405 to 450 degrees. CONCLUSION: Our data favor the idea that the intrinsic 3-dimensional cochlear morphology contributes to the risk for insertion trauma during cochlear implantation at specific locations.

Ventricular shape biomarkers for Alzheimer's disease in clinical MR images.

The aim of this work was to identify ventricular shape-based biomarkers in MR images to discriminate between patients with Alzheimer's disease (AD) and healthy elderly. Clinical MR images were collected for 58 patients and 28 age-matched healthy controls. After normalizing all the images the ventricular cerebrospinal fluid was semiautomatically extracted for each subject and an innovative technique for fully automatic shape modeling was applied to generate comparable meshes of all ventricles. The search for potential biomarkers was carried out with repeated permutation tests: results highlighted well-defined areas of the ventricular surface being discriminating features for AD: the left inferior medial temporal horn, the right medial temporal horn (superior and inferior), and the areas close to the left anterior part of the corpus callosum and the head of the right caudate nucleus. The biomarkers were then used as features to build an intelligent machine for AD detection: a Support Vector Machine was trained on AD and healthy subjects and subsequently tested with leave-1-out experiments and validation tests on previously unseen cases. The results showed a sensitivity of 76% for AD, with an overall accuracy of 84%, proving that suitable biomarkers for AD can be detected in clinical MR images.

Caudate nucleus hypointensity in the elderly is associated with markers of neurodegeneration on MRI.

In this study we investigated patterns of hypointense basal ganglia on T2*-weighted magnetic resonance imaging (MRI) in 413 non-demented elderly (range: 70-82 years, mean 77 years; male/female: 177/239). In addition, we assessed associations between these patterns and age-related changes in the brain. Three patterns were noted: hypointensity limited to the globus pallidus (group I; n=30; 7%), hypointensity of both globus pallidus and putamen (group II; n=272; 66%), and hypointensity of globus pallidus, putamen and caudate nucleus (group III; n=111; 27%). Group III demonstrated a higher volume of white matter hyperintensities, more atrophy, decreased whole brain magnetization transfer ratios and increased T2-values compared to groups I and II. No differences were observed between groups I and II. From this study we conclude that hypointensity of the caudate nucleus is associated with a higher load of age-related cerebral changes. These data suggest that hypointensity of the caudate nucleus could be a new biomarker of age-related changes in the brain.

MMSE scores correlate with local ventricular enlargement in the spectrum from cognitively normal to Alzheimer disease.

In this work, we aimed at correlating focal atrophy in periventricular structures with cognitive function, in the spectrum from healthy subjects to severe Alzheimer disease: 28 subjects with normal cognition and 84 patients presenting various degrees of cognitive impairment were included in the study. The cognitive level of each subject was assessed with the Mini-Mental State Examination (MMSE). Atrophy in periventricular structures was inferred by modeling and analyzing local shape variations of brain ventricles: for a given subject, we distinguished between the severity of atrophy, estimated as local enlargement (in mm) of the ventricular surface relative to an average normal subject, and the extent of atrophy, defined as the percentage of the ventricular surface (global or per anatomical region) significantly different from an average control. Linear regression across subjects was performed to evaluate the correlation between atrophy and MMSE score. The severity of atrophy showed good correlation with MMSE score in the left thalamus, the left temporal horn, the left corona radiata, and the right caudate nuclei. The extent of atrophy showed no significant correlations. In conclusion, the MMSE scores correlate with localized depth of atrophy in well-defined periventricular structures.

Shape differences of the brain ventricles in Alzheimer's disease.

The brain ventricles are surrounded by gray and white matter structures that are often affected in dementia in general and Alzheimer's disease (AD) in particular. Any change of volume or shape occurring in these structures must affect the volume and shape of the ventricles. It is well known that ventricular volume is significantly higher in AD patients compared to age-matched healthy subjects. However, the large overlap between the two volume distributions makes the measurement unsuitable as a biomarker of the disease. The purpose of this work was to assess whether local shape differences of the ventricles can be detected when comparing AD patients and controls. In this work, we captured the ventricle's shape and shape variations of 29 AD subjects and 25 age-matched controls, using a fully automatic shape modeling technique. By applying permutation tests on every single node of a mesh representation of the shapes, we identified local areas with significant differences. About 22% of an average surface of the ventricles presented significant difference (P < 0.05) ( approximately 14% of the left against approximately 7% of the right side). We found out that in patients with Alzheimer disease, not only the lateral horns were significantly affected, but also the areas adjacent to the anterior corpus callosum, the splenium of the corpus callosum, the amygdala, the thalamus, the tale of the caudate nuclei (especially the left one), and the head of the left caudate nucleus.

Detection of change in CNS involvement in neuropsychiatric SLE: a magnetization transfer study.

PURPOSE: To assess whether magnetization transfer imaging (MTI) parameters change in correspondence with clinical changes in NPSLE patients. MATERIALS AND METHODS: Nineteen female patients (mean age=37.5 years, range=19-64) underwent MTI on at least two separate occasions (mean time between scans=25.4 months, range=5.4-52.3 months). Twenty-four pairs of scans of 19 patients were available. Each patient's clinical course was classified as improved, stable, or deteriorated. Whole-brain magnetization transfer ratio (MTR) histograms were generated. The peak height of these histograms was used as an estimate of parenchymal integrity. Based on the change in clinical status, paired examinations were grouped and tested for significant differences between the first and second examinations using paired-samples t-tests. RESULTS: Four patients clinically deteriorated, all patients showed a significant peak height decrease (mean decrease=8.6%, P=0.02), and in 14 patients with stable disease the peak height did not change significantly (mean increase=0.4%). Six patients clinically improved, and all showed a significant relative peak height increase (mean increase=12.0%, P=0.02). CONCLUSION: The peak height of whole-brain MTR histograms corresponds to changes in the clinical status of individual NPSLE patients. This suggests that MTI can be a valuable tool in the clinical assessment of such patients.

Fully automatic shape modelling using growing cell.

In this paper, we present a new framework for shape modelling and analysis: we suggest to look at the problem from a pattern recognition point of view, and claim that under this prospective several advantages are achieved. The modelling of a surface with a point distribution model is seen as an unsupervised clustering problem, and tackled by using growing cell structures. The adaptation of a model to new shapes is studied as a classification task, and provides a straightforward solution to the point correspondence problem in active shape modelling. The method is illustrated and tested in 3D synthetic datasets and applied to the modelling of brain ventricles in an elderly population.

Neuropsychological correlates of MRI measures in the continuum of cognitive decline at old age.

OBJECTIVE: To investigate the independent associations between medial temporal lobe atrophy and white matter hyperintensities (WMH) and cognitive functions in the elderly. METHODS: Cognitive functions of 41 Alzheimer's disease patients, 20 patients with mild cognitive impairment and 28 elderly subjects without memory complaints were assessed using a neuropsychological test battery. Quantitative MRI measures of medial temporal lobe volume and WMH were obtained. Multiple regression analyses were performed to assess the independent contribution of MRI measures to impairment in several cognitive functions. RESULTS: Scores on the Wechsler Memory Scale and Trails B depended selectively on medial temporal lobe volume, whereas WMH selectively contributed to performance on Trails A. Medial temporal lobe volume and WMH both contributed to scores on the Cambridge Cognitive Examination and the Boston naming task. CONCLUSIONS: MRI measures suggestive of Alzheimer-type pathology and microvascular pathology independently contribute to cognitive decline at old age. Memory impairment as measured using the Wechsler Memory Scale and performance on Trails B primarily depended on medial temporal lobe atrophy. Psychomotor slowness, as measured using Trails A, mainly depended on WMH. These results suggest that vascular pathology and Alzheimer-type pathology each have specific cognitive correlates.