Severity Of White Matter Changes Research Articles

Evaluation of brain white matter changes on MRI in patients newly diagnosed with obstructive sleep apnea compared with the control group

BackgroundObstructive sleep apnea (OSA) is nowadays introduced as a risk factor for white matter brain changes. Research on OSA and white matter changes provides contradictory evidence for the contextual link between the two conditions. This study aimed to determine the prevalence and severity of OSA and changes in the brain's white matter and the relationship between severity levels of both diseases.MethodsThis was a cross-sectional study in which 40 patients with OSA and 40 patients without OSA underwent polysomnography to determine the severity of OSA and MRI for detecting white matter changes. The severity of white matter changes was classified according to the age-related white matter change (ARWMC) score, and the severity of OSA based on the apnea–hypopnea index (AHI). To evaluate the independent effect of OSA on white matter changes, a multivariate regression model, including the severity of OSA and risk factors, was used.Results76.5% of affected people did not show any changes, and from 13 (32.5%) patients with OSA who experienced white matter changes, 10% were mild, and 22.5% were moderate to severe changes. The white matter changes score increased with increasing OSA severity. The univariate analysis also showed a significant positive correlation between OSA severity and ARWMC score.ConclusionOur major finding was that moderate to severe OSA was independently associated with the prevalence of white matter changes. We also observed a higher prevalence of moderate to severe OSA associated with increasing white matter changes, suggesting that the severity of the disease affects brain structural modification.

Diffusion Tensor Imaging Shows More Extensive White Matter Changes in Frontal than in Temporal Lobe Epilepsy

Introduction: FLE is known to have a poorer prognosis than TLE. We compared the extent of white matter changes in these groups using diffusion tensor imaging-based tractography. Methods: 20 tracts each were made in five TLE and six FLE patients (bilateral FORX, CGC, PH, UF, SLF, ILF, IFOF, ATR, CST; FMajor and FMinor) and their FA values compared. Results: The TLE group had decreased FA of all ipsilateral fibres except IFOF, with a statistically significant decrease in FORX and UF. The FLE group had a significant decrease (p< 0.05) in the FA values of contralateral ATR and CST. A few contralateral tracts (PH, UF, SLF, IFOF) and ipsilateral FORX and ILF also showed (statistically nonsignificant) decreased mean FA. Mann-Whitney U test comparing ipsilateral nine fibre pairs of FLE vs. TLE was non-significant and significant (p<0.05) only for CST in contralateral fibre comparison. However, a generalised decrease in all fibre FA in FLE vs. TLE was noticed, except for the ‘intimate’ temporal fibres, viz., FORX and PH. The mean FA of all tracts was 0.4982 and 0.5201 for FLE and TLE, respectively (p<0.05). The mean FMajor and FMinor FA were 0.6146 vs. 0.6702 and 0.5598 vs. 0.5917 in FLE vs. TLE, respectively. Conclusion: Tractography based FA value comparison reveals more extensive and severe white matter changes in FLE than in TLE.

Insulin resistance based on postglucose load measure is associated with prevalence and burden of cerebral small vessel disease

IntroductionCerebral small vessel disease (cSVD) is highly prevalent and results in irreversible cognitive impairment and reduced quality of life. Previous studies reported controversial associations between insulin resistance and cSVD. Here,...

Cognitive dysfunction and white matter hyperintensities in Fabry disease.

Fabry disease (FD) is an X-linked lysosomal storage disorder with multi-system involvement including cerebrovascular disease. Patients with FD also have a high risk of ischaemic stroke and TIA. White matter hyperintensities are common, but their clinical impact on cognition remains uncertain. Previous studies have examined the neuropsychological profile of FD, but have been inconclusive in part due to methodological limitations including small sample sizes. We sought to address these limitations in a case-control study of 26 patients with Fabry disease with mild to moderate disease symptoms matched with 18 healthy controls for age and premorbid intellectual level. We obtained detailed neuropsychological data and MRI neuroimaging data on the severity of white matter changes. Mood was accounted for as a possible confounder. Our results showed significant compromise of executive functions and information processing speed for the FD group. Error analyses suggested that the compromise of executive functions could not be entirely accounted for by slowed information processing speed. We demonstrated significant correlations between cognitive decline and the overall volume of white matter hyperintensities in the FD group. Our results point to significant compromise of cognition in FD even without stroke or mood difficulties. This suggests that neuropsychological assessment and rehabilitation should be routinely offered to patients with FD.

The influence of cerebrovascular disease in dementia with Lewy bodies and Parkinson's disease dementia.

Lewy body dementia (LBD), including dementia with Lewy bodies (DLB) and Parkinson's disease dementia, is a common form of neurodegenerative dementia. The frequency and influence of comorbid cerebrovascular disease is not understood but has potentially important clinical management implications. A systematic literature search was conducted (MEDLINE and Embase) for studies including participants with DLB and/or Parkinson's disease dementia assessing cerebrovascular lesions (imaging and pathological studies). They included white matter changes, cerebral amyloid angiopathy, cerebral microbleeds (CMB), macroscopic infarcts, microinfarcts and intracerebral haemorrhage. Of 4411 articles, 63 studies were included. Cerebrovascular lesions commonly studied included white matter changes (41 studies) and CMB (18 studies). There was an increased severity of white matter changes on magnetic resonance imaging (visualized as white matter hyperintensities), but not neuropathology, in LBD compared to Parkinson's disease without dementia and age-matched controls. CMB prevalence in DLB was highly variable but broadly similar to Alzheimer's disease (0%-48%), with a lobar predominance. No relationship was found between large cortical or small subcortical infarcts or intracerebral haemorrhage and the presence of LBD. The underlying mechanisms of white matter hyperintensities in LBD require further exploration, as their increased severity in LBD was not supported by neuropathological examination of white matter. CMB in LBD had a similar prevalence to Alzheimer's disease. There is a need for larger studies assessing the influence of cerebrovascular lesions on clinical symptoms, disease progression and outcomes.

Post-Mortem Comparison of the Incidence and the Distribution of Cerebrovascular Lesions Using Additional 7.0-Tesla Magnetic Resonance Imaging in Cognitive Normal Young, Middle-Aged, and Elderly Persons

Regional brain atrophy and an escalation in vascular risk are associated to increasing age in normal cognitive healthy persons. The present post-mortem study compares the incidence of cerebrovascular lesions between young-aged, middle-aged, and elderly cognitive normal persons with additional 7.0-tesla MRI). The patients consisted of 10 young adults, 20 middle-aged adults, and 14 elderly ones. In addition to the macroscopic visible cerebrovascular lesions, a whole coronal section of a cerebral hemisphere was taken for the semi-quantitative evaluation of white matter changes (WMCs), cortical micro-infarcts (CoMIs), and cortical micro-bleeds (CoMBs). Three separate coronal sections of a cerebral hemisphere were submitted to T2 and T2* MRI sequences for semi-quantitative evaluation of the small cerebrovascular lesions. Arterial hypertension, hypercholesterolemia, and the use of anti-thrombotic agents were found to be more frequent in the elderly group, and to a lesser degree in the middle-aged group. The neuropathological examination showed more severe WMCs and an increased number of CoMBs in the elderly group. On NMR the increased severity of WMCs was only found in the frontal and occipital sections of the elderly brains. CoMIs were augmented in the central and occipital sections of the middle-aged and the elderly persons. CoMBs were increased in all coronal sections of elderly as well as middle-aged groups. CoMIs reflect most significantly the cerebrovascular involvement of the aging brain. The increase of WMCs is probably mostly related the aging related neurodegenerative progression. The increase of CoMBs is probably due to mixed cerebrovascular and neurodegenerative pathology.

Hemodynamic Significance of Middle Cerebral Artery Stenosis Associated With the Severity of Ipsilateral White Matter Changes.

Background: Previous studies conflicted in the association between intracranial atherosclerotic stenosis (ICAS) and the severity of white matter changes (WMC).Aims: We aimed to investigate the relationships between the severity of luminal stenosis and the hemodynamic significance of middle cerebral artery (MCA) stenosis, and the severity of ipsilateral WMC.Methods: In this cross-sectional study, patients with a recent ischemic stroke or transient ischemic attack and a 50–99% MCA-M1 stenosis in the Chinese Intracranial Atherosclerosis study cohort were analyzed. The post- to pre-stenotic signal intensity ratio (SIR) was obtained in time-of-flight MR angiography (MRA) to represent the hemodynamic significance of MCA-M1 stenosis, with a lower SIR indicating a hemodynamically more severe lesion. The severity of ipsilesional WMC was assessed by an age-related WMC (ARWMC) scale in T2-weighted fluid attenuated inversion recovery MR imaging. The relationships between the degree of MCA-M1 stenosis, SIR, and ipsilesional ARWMC scale were analyzed. The MCA-M1 lesion with a higher percentage of stenosis was chosen for analyses in patients with bilateral MCA-M1 stenoses.Results: Among 180 subjects (mean age, 64 years), a lower SIR of MCA-M1 stenosis (Spearman correlation coefficient, −0.543; p < 0.001), but not the degree of stenosis (p = 0.93), was significantly linearly correlated with a higher ipsilateral ARWMC. Multivariate ordinal logistic regression identified older age (OR = 1.037; 95% CI, 1.008–1.066; p = 0.011) and lower SIR (OR = 0.010; 95% CI, 0.002–0.058; p < 0.001) as independent predictors for more severe ipsilateral WMC.Conclusion: Patients with hemodynamically more severe ICAS are more likely to have more severe ipsilateral WMC. Longitudinal studies with sequential imaging exams may further reveal the impact of hemodynamic significance of ICAS on the development and progression of WMC.

A Comparison Study of Cilostazol and Aspirin on Changes in Volume of Cerebral Small Vessel Disease White Matter Changes: Protocol of a Multicenter, Randomized Controlled Trial.

Background and PurposeCerebral small vessel disease (CSVD) is the most common cause of vascular dementia and a major contributor to mixed dementia. CSVD is characterized by progressive cerebral white matter changes (WMC) due to chronic low perfusion and loss of autoregulation. In addition to its antiplatelet effect, cilostazol exerts a vasodilating effect and improves endothelial function. This study aims to compare the effects of cilostazol and aspirin on changes in WMC volume in CSVD.MethodsThe comparison study of Cilostazol and aspirin on cHAnges in volume of cerebral smaLL vEssel disease white matter chaNGEs (CHALLENGE) is a double blind, randomized trial involving 19 hospitals across South Korea. Patients with moderate or severe WMC and ≥ 1 lacunar infarction detected on brain magnetic resonance imaging (MRI) are eligible; the projected sample size is 254. Participants are randomly assigned to a cilostazol or aspirin group at a 1:1 ratio. Cilostazol slow release 200 mg or aspirin 100 mg are taken once daily for 2 years. The primary outcome measure is the change in WMC volume on MRI from baseline to 104 weeks. Secondary imaging outcomes include changes in the number of lacunes and cerebral microbleeds, fractional anisotropy and mean diffusivity on diffusion tensor imaging, and brain atrophy. Secondary clinical outcomes include all ischemic strokes, all vascular events, and changes in cognition, motor function, mood, urinary symptoms, and disability.ConclusionsCHALLENGE will provide evidence to support the selection of long-term antiplatelet therapy in CSVD.Trial RegistrationClinicalTrials.gov Identifier: NCT01932203

Obstructive sleep apnea and cerebral white matter change: a systematic review and meta-analysis.

Obstructive sleep apnea (OSA) can cause sleep fragmentation and intermittent hypoxemia, which are linked to oxidative stress. White matter changes (WMCs) representing cerebrovascular burden and are at risk factor for oxidative ischemic injury. The current study explores the mutual relationships between OSA and WMCs. We performed a systematic review of electronic databases for clinical studies investigating OSA and WMCs. Random-effects models were used for pooled estimates calculation. A total of 22 studies were included in the meta-analysis. The results revealed a significantly higher prevalence rate of WMCs [odds ratio (OR) 2.06, 95% confidence interval (CI) 1.52-2.80, p < 0.001] and significantly higher severity of WMCs (Hedges' g = 0.23, 95% CI 0.06-0.40, p = 0.009) in the patients with OSA than in controls. Furthermore, the results revealed a significantly higher apnea-hypopnea index (Hedges' g = 0.54, 95% CI 0.31-0.78, p < 0.001) and significantly higher prevalence rate of moderate-to-severe OSA (OR 2.86, 95% CI 1.44-5.66, p = 0.003) in the patients with WMCs than in controls, however there was no significant difference in the prevalence rate of mild OSA between the patients with WMCs and controls (OR 0.71, 95% CI 0.20-2.54, p = 0.603). OSA was associated with a higher prevalence and more severe WMCs, and the patients with WMCs had an increased association with moderate-to-severe OSA. Future large-scale randomized controlled trials with a longitudinal design are essential to further evaluate treatment in patients with OSA.

MRI Features and Site-specific Factors of Ischemic Changes in White Matter: A Retrospective Study.

Brain magnetic resonance imaging (MRI) of the elderly often reveals white matter changes (WMCs) with substantial variability across individuals. Our study was designed to explore MRI features and site-specific factors of ischemic WMCs. Clinical data of consecutive patients diagnosed with ischemic cerebral vascular disease who had undergone brain MRI were collected and analyzed. Multi-logistic regression analysis comparing patients with mild versus severe WMCs was performed to detect independent associations. Analyses of variance (ANOVAs) were used to detect regionally specific differences in lesions. We found that lesion distribution differed significantly across five cerebral areas, with lesions being predominant in the frontal lobe and parieto-occipital area. To explore WMCs risk factors, after adjusting for gender, diabetes mellitus, and hypertension, only age (P<0.01), creatinine (P=0.01), alkaline phosphatase (ALP) (P=0.01) and low-density lipoprotein cholesterol (LDL-C) (P=0.03) were found to be independently associated with severe WMCs. Age (P<0.001) was strongly associated with WMCs in the frontal lobe while hypertension was independently related to lesions in the basal ganglia (P=0.048) or infratentorial area (P=0.016). In conclusion, MRI of WMCs showed that ischemic WMCs occurred mostly in the frontal lobe and parieto-occipital area. The infratentorial area was least affected by WMCs. Typically, age-related WMCs were observed in the frontal lobes, while hypertension-related WMCs tended to occur in the basal ganglia and infratentorial area.

Effect of white matter changes on risk score for peri-procedural complications after carotid artery stenting

ObjectivesThe presence of more severe white matter changes (WMC) may be associated with a higher risk of peri-procedural strokes in patients undergoing carotid artery stenting (CAS). However, to what extent WMC affects peri-procedural risk of CAS is unclear. We aimed to evaluate the effect of WMC on peri-procedural complications by modifying a CAS peri-procedural risk scale through adding the assessment of WMC. Patients and methodsA database of patients undergoing CAS was sampled from 2007 to 2014 in a single Chinese medical center. Risk factors were evaluated for peri-interventional cerebral and cardiac events and mortality. A risk score including contralateral stenosis ≥ 50%, diabetes with HbA1c > 7%, age ≥ 80 years old, symptomatic stenosis or with an ulcer lesion was applied to predict peri-interventional risk. Age-related white matter change (ARWMC) score was calculated and added to this risk scale. The predictive power of the new scale was evaluated. Results151 patients were enrolled in the study. 14 peri-interventional events were recorded. Patients with peri-procedural complications had higher rates of diabetes (57.1% vs 18.2%, P = 0.001), contralateral stenosis (64.29% vs 32.85%, P = 0.019), coronary heart disease (42.9% vs 14.6%, P = 0.008) and ARWMC ≥ 7 (64.3% vs 25.5%, P = 0.002) compared with patients without peri-procedural complications. ARWMC ≥ 7 was an independent risk factor for peri-procedural complications from factors of the CAS scale after adjusting other confounders including contralateral stenosis ≥ 50%, HbA1c > 7%, age ≥ 80 years old and symptomatic stenosis or with an ulcer lesion. After the ARWMC score was added to the original scale, the AUC value of the new scale to predict the risk of peri-procedural complications after CAS was elevated (0.808 vs 0.730, p = 0.068). ConclusionMore severe WMC was a risk factor for peri-procedural complications after CAS in patients with carotid artery stenosis. ARWMC score may help to improve the predictive power of the risk scale for peri-procedural complications after CAS.

Corrigendum: White Matter Changes-Related Gait and Executive Function Deficits: Associations with Age and Parkinson's Disease.

[This corrects the article on p. 213 in vol. 9, PMID: 28713264.].

Location of white matter changes and response to donepezil in patients with Alzheimer's disease: A retrospective and observational study.

The response to donepezil in patients with Alzheimer's disease varies, and it is important to identify the potential responder before therapy. Cerebral white matter changes (WMC) are frequently observed in older patients, and the effect of WMC on therapeutic response remains controversial. The present study aimed to investigate the relationships between the location of WMC, severe WMC and the response to donepezil. Among 418 patients with Alzheimer's disease receiving donepezil, 196 patients were eligible for analysis. Five brain areas on each side were analyzed using computed tomography scans and the Age-Related White Matter Changes Rating Scale before therapy. The Cognitive Abilities Screening Instrument was used annually. Patients were defined as responders if their baseline Cognitive Abilities Screening Instrument score minus their follow-up Cognitive Abilities Screening Instrument score was ≤0. There was no significant difference in demographic data between responder and non-responder groups. Patients in the responder group had significantly less involvement of WMC in the frontal area (P = 0.0213) and nearly a trend for less involvement of WMC in the basal ganglia (P = 0.1103). After adjustment for age, sex, education, polymorphism of apolipoprotein E, hypertension and diabetes, WMC in the frontal area (OR 0.446, P = 0.0139) and basal ganglia (OR 0.243, P = 0.0380) were significantly associated with a reduced therapeutic response. Patients with WMC in the frontal area and basal ganglia had significant decreases in their therapeutic response to donepezil. The location of WMC, independent of their severity, might be associated with the therapeutic response in patient with Alzheimer's disease. Geriatr Gerontol Int 2018; 18: 123-129.

OBSERVATIONAL LONGITUDINAL STUDY OF BRAIN MRI CHARACTERISTICS AND CLINICAL MEASURES OF FUNCTION AND DISEASE PROGRESSION IN PATIENTS WITH DEMENTIA

Longitudinal brain magnetic resonance imaging (MRI) has shown that changes in white matter and medial temporal atrophy are biomarkers of Alzheimer's disease (AD); however, the correlation with MRI findings and progression of AD has not been fully established. In this prospective, 12-month observational study, consecutive dementia outpatients were recruited from 29 centers across South Korea. Baseline assessments included confirmation of AD (brain MRI data), cognitive function, dementia severity, activities of daily living (ADL), and AD medication use. Follow-up assessments were conducted at 6 and 12 months. Among the 899 enrolled patients with dementia, 748 were diagnosed with AD based on MRI assessment; 654 (87%) were using AD medications. In AD patients, changes in cognitive deficit were not correlated with changes in white matter on brain MRI and changes in IADL, but not other cognitive function, correlated with the changes in hippocampal atrophy on brain MRI. These results were more prominent in untreated group. Positive drinking status and higher CDR score were correlated with more severe white matter changes and age, dementia family history, physical exercise, and the results of neuropsychological assessment were correlated with hippocampal atrophy. We confirmed that there is a relationship between the loss of hippocampal volume in MRI and changes in IADL decline with AD patients, especially untreated group, and showed that patient's lifestyle behaviors are more important than non-modifiable factors in the progression of the MRI findings in this study.

White Matter Changes-Related Gait and Executive Function Deficits: Associations with Age and Parkinson's Disease.

Background: White matter changes (WMC) are a common finding among older adults and patients with Parkinson's disease (PD), and have been associated with, e.g., gait deficits and executive dysfunction. How the factors age and PD influence WMC-related deficits is, to our best knowledge, not investigated to date. We hypothesized that advanced age and presence of PD leads to WMC-related symptoms while practicing tasks with a low complexity level, and low age and absence of PD leads to WMC-related symptoms while practicing tasks with a high complexity level.Methods: Hundred and thirty-eight participants [65 young persons without PD (50–69 years, yPn), 22 young PD patients (50–69 years, yPD), 36 old persons without PD (70–89 years, oPn) and 15 old PD patients (70–89 years, oPD)] were included. Presence and severity of WMC were determined with the modified Fazekas score. Velocity of walking under single and dual tasking conditions and the Trail Making Test (TMT) were used as gait and executive function parameters. Correlations between presence and severity of WMC, and gait and executive function parameters were tested in yPn, yPD, oPn, and oPD using Spearman's rank correlation, and significance between groups was evaluated with Fisher's z-transformed correlation coefficient.Results: yPn and yPD, as well as oPn and oPD did not differ regarding demographic and clinical parameters. Severity of WMC was not significantly different between groups. yPn and yPD displayed significant correlations of WMC with executive function parameters at low levels of task complexity, oPn at intermediate, and oPD at high complexity levels.Conclusion: This study argues for a relevant association of age and PD-related brain pathology with WMC-related gait and executive function deficits.

Non-linear correlation between cumulative sub-concussive head impact trauma and severity of localised brain white matter changes in college athletes

ObjectiveTest for a dose dependent relationship between cumulative sub-concussive head trauma loading and localised changes of brain white matter in college athletes.DesignProspective cohort studySettingNCAA Division I Women’s SoccerParticipants10 players were monitored for head impacts throughout a soccer season using wearable sensors. Linear and rotational accelerations recorded during impacts were processed to calculate the cumulative impact power. Diffusion spectrum imaging (DSI) data were acquired at season start and at 3 additional intervals. 11 age and gender matched control data sets were acquired.InterventionOne athlete suffered a concussion, was removed from play for neurocognitive testing, and entered a supervised return-to-play protocol.Outcome measuresCumulative impact power was used as a measure of the head trauma load accumulated prior to each MRI. Multi-dimensional anisotropy (MDA) values assessed localised severity of white matter changes. Session specific differences between each player’s MDA values and those of the control population were used to relate cumulative impact power and the severity of white matter changes.Main resultsHighly significant clusters of abnormal voxels were observed in athletes with no diagnosed concussion symptoms. Injury severity correlated with cumulative head impact power and demonstrated a pronounced threshold behaviour. MDA diffusion changes were located mainly within the frontal and occipital cortex at the gray-white boundary, and to a lesser degree in deep subcortical areas where there is a higher proportion of crossing fibres.ConclusionsThis cohort demonstrates dose dependent changes in white matter integrity as a function of cumulative sub-concussive head trauma.Competing interestsSG is supported, in part, by a research grant from X2 Biosystems and a General Electric-National Football League Head Health Challenge award.

Small vessel disease and clinical outcomes after IV rt-PA treatment

Cerebral small vessel disease (SVD) contributes to dementia and disability in the elderly, and may negatively affect stroke outcomes. We aimed to evaluate to what extent single features and global burden of SVD detected with magnetic resonance (MR) are associated with worse outcomes in patients with ischaemic stroke treated with intravenous thrombolysis. We accessed anonymized data and MR images from the Stroke Imaging Repository (STIR) and the Virtual International Stroke Trials Archive (VISTA) Imaging. We described SVD features using validated scales and quantified the global burden of SVD with a combined score. Our mainoutcome was the modified Rankin Scale (mRS) at 90 days after stroke. We used logistic regression and ordinal regression models (adjusted for age, sex, stroke severity, onset to treatment time) to examine the associations between each SVD feature, SVD global burden and clinical outcomes. A total of 259 patients had MR scans available at baseline (mean age±SD=68.7±15.5 years; 131 [49%] males). After adjustment for confounders, severe white matter changes were associated with disability (OR=5.14; 95%CI=2.30-11.48), functional dependency (OR=4.38; 95%CI=2.10-9.13) and worse outcomes in ordinal analysis (OR=2.71; 95%CI=1.25-5.85). SVD score was associated with disability (OR=1.66; 95%CI=1.03-2.66) and functional dependency (OR=1.47; 95%CI=1.00-2.45). Lacunes, enlarged perivascular spaces and brain atrophy showed no association with clinical outcomes. Our results suggest that SVD negatively affects stroke outcomes after intravenous thrombolysis. Although white matter changes seem to be the major driver in relation to worse outcomes, global estimation of SVD is feasible and may provide helpful information.

Retinal structure assessed by OCT as a biomarker of brain development in children born small for gestational age

PurposeTo identify differences in neuronal tissue from retinal and brain structures in children born small for gestational age (SGA) with no abnormality in neonatal brain ultrasonography and no previous neurological...

Cerebrovascular Lesions in Pick Complex Diseases – A Neuropathological Study with a 7.0-Tesla Magnetic Resonance Imaging Study

Pick complex refers to a spectrum of diseases that include the presence of tau. The main neuropathological phenotypes comprise tau-frontotemporal lobar degeneration (tau-FTLD), progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD). The present neuropathological study investigated the incidence of cerebrovascular lesions, including the small lesions detected microscopically on a large coronal section of a cerebral hemisphere at the level of the mammillary body. In addition the severity and distribution of white matter changes (WMCs), cortical microinfarcts (CoMIs) and cortical microbleeds (CoMBs) are examined with 7.0-tesla magnetic resonance imaging (MRI) on three coronal sections of a cerebral hemisphere. On neuropathological examination severe WMCs and more CoMBs are observed in tau-FTLD, while the latter are also more frequent in CBD. The MRI examination shows that severe WMCs are present in the frontal section of not only the tau-FTLD, but the PSP and CBD brains, albeit to a lesser degree. Severe WMCs and the increased number of CoMBs are related directly to the neurodegenerative process and do not represent additional cerebrovascular disease. The Pick complex diseases have a low incidence of real cerebrovascular lesions in common.

Frequency and topography of small cerebrovascular lesions in vascular and in mixed dementia: a post-mortem 7-tesla magnetic resonance imaging study with neuropathological correlates.

<i><b>Introduction</b>: Mixed dementia (MixD) refers to a combination of definite Alzheimer's disease (AD) and vascular encephalopathy. The existence of a "pure" type of vascular dementia (VaD) is controversial. There is a need to find magnetic resonance imaging (MRI) characteristics allowing the distinction between VaD and MixD. The present post-mortem 7.0-tesla MRI compares the frequency or severity and the topography of the small cerebrovascular lesions in brains of patients with VaD and with MixD. <b>Material and methods</b>: Based on neuropathological criteria, 14 brains were classified as VaD, 24 as MixD and 11 as controls. Three coronal sections of a cerebral hemisphere and a horizontal section of a cerebellar hemisphere underwent T2 and T2* 7.0-tesla MRI examination. The mean values and topographic distribution of white matter changes (WMCs), lacunar infarcts (LIs), cortical microbleeds (CoMBs) and cortical microinfarcts (CoMIs) were determined and compared between the different groups. <b>Results</b>: Compared to the controls, both VaD and MixD brains had significantly more severe WMCs and increased numbers of CoMBs and CoMIs. Lacunar infarcts predominated only in the VaD cases. On mutual comparison of VaD and MixD brains, CoMBs and CoMIs predominated in the frontal lobe and the cerebellum of VaD, while were mainly present in the occipital lobe of MixD. White matter changes predominated in the temporal lobe of MixD cases. Lacunar infarcts were significantly increased in the corona radiata and putamen of VaD patients. <b>Conclusions</b>: The present post-mortem MRI study shows clear differences in the distribution and the types of cerebrovascular lesions on high-field MRI, confirming that VaD and MixD are different diseases. </i>.