New development in diagnosis of vascular cognitive impairment

Evaluating the Role of Reduced Oxygen Saturation and Vascular Damage in Traumatic Brain Injury Using Magnetic Resonance Perfusion-Weighted Imaging and Susceptibility-Weighted Imaging and Mapping

The cerebral vasculature, along with neurons and axons, is vulnerable to biomechanical insult during traumatic brain injury (TBI). Trauma-induced vascular injury is still an underinvestigated area in TBI research. Cerebral blood flow and metabolism could be important future treatment targets in neural critical care. Magnetic resonance imaging offers a number of key methods to probe vascular injury and its relationship with traumatic hemorrhage, perfusion deficits, venous blood oxygen saturation changes, and resultant tissue damage. They make it possible to image the hemodynamics of the brain, monitor regional damage, and potentially show changes induced in the brain's function not only acutely but also longitudinally following treatment. These methods have recently been used to show that even mild TBI (mTBI) subjects can have vascular abnormalities, and thus they provide a major step forward in better diagnosing mTBI patients.

Susceptibility Weighted Imaging and Mapping of Micro-Hemorrhages and Major Deep Veins after Traumatic Brain Injury

Micro-hemorrhages are a common result of traumatic brain injury (TBI), which can be quantified with susceptibility weighted imaging and mapping (SWIM), a quantitative susceptibility mapping approach. A total of 23 TBI patients (five women, 18 men; median age, 41.25 years old; range, 21.69-67.75 years) with an average Glasgow Coma Scale score of 7 (range, 3-15) at admission were recruited at mean 149 d (range, 57-366) after injury. Susceptibility-weighted imaging data were collected and post-processed to create SWIM images. The susceptibility value of small hemorrhages (diameter ≤10 mm) and major deep veins (right septal, left septal, central septal, right thalamostriate, left thalamostriate, internal cerebral, right basal vein of Rosenthal, left basal vein of Rosenthal, and pial veins) were evaluated. Different susceptibility thresholds were tested to determine SWIM's sensitivity and specificity for differentiating hemorrhages from the veins. A total of 253 deep veins and 173 small hemorrhages were identified and evaluated. The mean susceptibility of hemorrhages was 435±206 parts per billion (ppb) and the mean susceptibility of deep veins was 108±56 ppb. Hemorrhages showed a significantly higher susceptibility than all deep veins (p<0.001). With different thresholds (250, 227 and 200 ppb), the specificity was 97%, 95%, and 92%, and the sensitivity was 84%, 90%, and 92%, respectively. These results show that SWIM could be used to differentiate hemorrhages from veins in TBI patients in a semi-automated manner with reasonable sensitivity and specificity. A larger cohort will be needed to validate these findings.

The use of the mini-mental state examination and the clock-drawing test for dementia in a tertiary hospital

INTRODUCTION

An early and a quick identification of dementia is desirable to improve the overall care to the affected persons in the developing countries. The aim of this study was to evaluate the discriminative abilities of the Mini Mental State Examination (MMSE) and the Clock Drawing Test (CDT) in differentiating the demented patients from the controls and also the differentiation between the different types of dementia.

PATIENTS AND METHODS

This study was designed to evaluate the patients with varied types and severities of dementia, who were diagnosed by using the Clinical Dementia Rating (CDR) scale. All the patients completed the MMSE and the simplified CDT.

RESULTS

This study included 197 patients with an age range of 43-79 years. Fifty-one patients (25.9%) were diagnosed with Alzheimer Dementia (AD), 37 patients (18.8%) with Vascular Dementia (VD), 23 patients (11.7%) with Parkinson's Disease Dementia (PDD) and 86 patients (43.6%) with other variants of dementia. The total MMSE score of the enrolled patients was significantly lower as compared to that of the control subjects, with a non-significant difference between the varied diagnoses. The total CDT scores were significantly lower in the patients as compared to those in the controls, with significantly lower scores in the PDD group as compared to those in the AD group. The patients who had AD showed non-significantly higher CDT scores as compared to the patients who had vascular and other types of dementia.

CONCLUSION

A combined application of both MMSE and CDT can identify the persons with a cognitive affection and this may be a useful tool for the diagnosis of the non Alzheimer's type of dementia.

Blood-brain barrier permeability and long-term clinical and imaging outcomes in cerebral small vessel disease

BACKGROUND AND PURPOSE

Increased blood-brain barrier (BBB) permeability occurs in cerebral small vessel disease. It is not known if BBB changes predate progression of small vessel disease.

METHODS

We followed-up patients with nondisabling lacunar or cortical stroke and BBB permeability magnetic resonance imaging after their original stroke. Approximately 3 years later, we assessed functional outcome (Oxford Handicap Score, poor outcome defined as 3-6), recurrent neurological events, and white matter hyperintensity (WMH) progression on magnetic resonance imaging.

RESULTS

Among 70 patients with mean age of 68 (SD ± 11) years, median time to clinical follow-up was 39 months (interquartile range, 30-45) and median Oxford Handicap Score was 2 (interquartile range, 1-3); poor functional outcome was associated with higher baseline WMH score (P<0.001) and increased basal ganglia BBB permeability (P=0.046). Among 48 patients with follow-up magnetic resonance imaging, WMH progression at follow-up was associated with baseline WMH (ANCOVA P<0.0001) and age (ANCOVA P=0.032).

CONCLUSIONS

Further long-term studies to evaluate the role of BBB dysfunction in progression of small vessel disease are required in studies that are large enough to account for key prognostic influences such as baseline WMH and age.

How much do focal infarcts distort white matter lesions and global cerebral atrophy measures?

BACKGROUND

White matter lesions (WML) and brain atrophy are important biomarkers in stroke and dementia. Stroke lesions, either acute or old, symptomatic or silent, are common in older people. Such stroke lesions can have similar signals to WML and cerebrospinal fluid (CSF) on magnetic resonance (MR) images, and may be classified accidentally as WML or CSF by MR image processing algorithms, distorting WML and brain atrophy volume from the true volume. We evaluated the effect that acute or old stroke lesions at baseline, and new stroke lesions occurring during follow-up, could have on measurement of WML volume, cerebral atrophy and their longitudinal progression.

METHODS

We used MR imaging data from patients who had originally presented with acute lacunar or minor cortical ischaemic stroke symptoms, recruited prospectively, who were scanned at baseline and about 3 years later. We measured WML and CSF volumes (ml) semi-automatically. We manually outlined the acute index stroke lesion (ISL), any old stroke lesions present at baseline, and new lesions appearing de novo during follow-up. We compared baseline and follow-up WML volume, cerebral atrophy and their longitudinal progression excluding and including the acute ISL, old and de novo stroke lesions. A non-parametric test (Wilcoxon's signed rank test) was used to compare the effects.

RESULTS

Among 46 patients (mean age 72 years), 33 had an ISL visible on MR imaging (median volume 2.05 ml, IQR 0.88-8.88) and 7 of the 33 had old lacunes at baseline: WML volume was 8.54 ml (IQR 5.86-15.80) excluding versus 10.98 ml (IQR 6.91-24.86) including ISL (p < 0.001). At follow-up, median 39 months later (IQR 30-45), 3 patients had a de novo stroke lesion; total stroke lesion volume had decreased in 11 and increased in 22 patients: WML volume was 12.17 ml (IQR 8.54-19.86) excluding versus 14.79 ml (IQR 10.02-38.03) including total stroke lesions (p < 0.001). Including/excluding lacunes at baseline or follow-up also made small differences. Twenty-two of the 33 patients had tissue loss due to stroke lesions between baseline and follow-up, resulting in a net median brain tissue volume loss (i.e. atrophy) during follow-up of 24.49 ml (IQR 12.87-54.01) excluding versus 24.61 ml (IQR 15.54-54.04) including tissue loss due to stroke lesions (p < 0.001). Including stroke lesions in the WML volume added substantial noise, reduced statistical power, and thus increased sample size estimated for a clinical trial.

CONCLUSIONS

Failure to exclude even small stroke lesions distorts WML volume, cerebral atrophy and their longitudinal progression measurements. This has important implications for design and sample size calculations for observational studies and randomised trials using WML volume, WML progression or brain atrophy as outcome measures. Improved methods of discriminating between stroke lesions and WML, and between tissue loss due to stroke lesions and true brain atrophy are required.

Vascular Cognitive Impairment (VCI) after non-embolic ischemic stroke during a 12-month follow-up in Brazil

VCI represents a spectrum of cognitive impairments associated with stroke, vascular brain injury, or subclinical disease ranging from the least to most severe manifestations. Few studies are available on the prevalence of post-stroke VCI and none have been conducted in Brazil.

Cerebral microbleeds and cognition in cerebrovascular disease: an update

Sporadic cerebral small vessel disease is a major cause of cognitive impairment. MRI is an important tool for detecting and mapping cerebral small vessel disease in vivo. Lacunes and white matter changes are recognized as characteristic MRI manifestations of small vessel disease. Cerebral microbleeds (CMBs) - small, perivascular haemorrhages seen as well-demarcated, hypointense, rounded lesions on MRI sequences sensitive to magnetic susceptibility - are a more recently recognized MRI marker of small vessel pathology. CMBs are increasingly found in various patient populations and disease settings, including first-ever and recurrent ischaemic or haemorrhagic stroke, Alzheimer's disease, vascular cognitive impairment and healthy elderly individuals. Increasing evidence suggests that the anatomical distribution of CMBs (lobar or deep) may have diagnostic value in detecting small vessel disease subtypes including hypertensive arteriopathy and cerebral amyloid angiopathy. However, the relevance of CMBs for cognitive impairment remains uncertain. The study of CMBs and cognition in populations with cerebrovascular disease presents a special challenge as they coexist and correlate with other cerebrovascular pathologies. This review updates current thinking on how CMBs may be relevant in the study of cognitive impairment in populations with cerebrovascular disease, and how they can contribute in understanding the links between cerebrovascular and degenerative pathologies.

Vascular dementia: Diagnostic criteria and supplementary exams. Recommendations of the Scientific Department of Cognitive Neurology and Aging of the Brazilian Academy of Neurology. Part I

Vascular dementia (VaD) is the most prevalent form of secondary dementia and the second most common of all dementias. The present paper aims to define guidelines on the basic principles for treating patients with suspected VaD (and vascular cognitive impairment - no dementia) using an evidence-based, systematized approach. The knowledge used to define these guidelines was retrieved from searches of several databases (Medline, Scielo, Lilacs) containing scientific articles, systematic reviews, meta-analyses, largely published within the last 15 years or earlier when pertinent. Information retrieved and selected for relevance was used to analyze diagnostic criteria and to propose a diagnostic system encompassing diagnostic criteria, anamnesis, as well as supplementary and clinical exams (neuroimaging and laboratory). Wherever possible, instruments were selected that had versions previously adapted and validated for use in Brazil that take into account both schooling and age. This task led to proposed protocols for supplementary exams based on degree of priority, for application in clinical practice and research settings.