Neuropsychological Features of Microbleeds and Cortical Microinfarct Detected by High Resolution Magnetic Resonance Imaging

The performance of patients with cerebral microbleeds in different cognitive tests: A cross-sectional study

Background

The clinical features and pathological process of cerebral microbleed (CMB)-related cognitive impairment are hot topics of cerebral small vessel disease (CSVD). However, how to choose a more suitable cognitive assessment battery for CMB patients is still an urgent issue to be solved. This study aimed to analyze the performance of CMB patients on different cognitive tests.

Methods

This study was designed as a cross-sectional study. The five main markers of CSVD (including the CMB, white matter hyperintensities, perivascular spaces, lacunes and brain atrophy) were assessed according to magnetic resonance imaging. The burden of CMB was categorized into four grades based on the total number of lesions. Cognitive function was assessed by Mini-Mental State Examination (MMSE), Trail-Making Test (TMT, Part A and Part B), Stroop color-word test (Stroop test, Part A, B and C), Verbal Fluency Test (VF, animal), Digit-Symbol Substitution Test (DSST), Digit Cancellation Test (DCT) and Maze. Multiple linear regression analysis was conducted to analyze the association between CMB and cognitive findings.

Results

A total of 563 participants (median age of 69 years) were enrolled in this study, including 218 (38.7%) CMB patients. CMB patients showed worse performance than non-CMB subjects in each cognitive test. Correlation analysis indicated the total number of CMB lesions had positive correlations with the time of TMT, Maze and Stroop test, and negative correlations with the performance of MMSE, VF, DSST, and DCT. After the adjustment for all the potential confounders by linear regression, the CMB burden grade was correlated with the performance of VF, Stroop test C, Maze and DCT.

Conclusion

The presence of CMB lesions was associated with much worse cognitive performances. In VF, Stroop test C, Maze and DCT, the correlations between CMB severity and assessment results were more significant. Our study further confirmed that the attention/executive function domain was the most commonly evaluated in CMB, which provided a picture of the most utilized tools to analyze the prognostic and diagnostic value in CMB.

3D Cube FLAIR plus HyperSense compressed sensing is superior to 2D T2WI FLAIR scanning regarding image quality, spatial resolution, detection rate for cortical microinfarcts

3-dimention (3D) Cube isotropic volumetric magnetic resonance imaging (MRI) facilitates comprehensive recognition of microinfarcts while it takes long scanning time. HyperSense compressed sensing is an emerging technique for accelerating MRI acquisition to reduce scanning time, while its application along with 3D Cube MRI for microinfarcts is seldom reported. Therefore, this study aimed to investigate the efficiency of 3D Cube FLAIR plus HyperSense compressed sensing technique versus conventional 2-dimention (2D) FLAIR scanning in the detection of cortical microinfarcts (CMIs). Totally 59 patients with cerebrovascular disease were enrolled then scanned by 3D Cube FLAIR plus HyperSense compressed sensing and 2D T2WI FLAIR sequences. The image quality scores, signal-to-noise ratio (SNR) for gray matter (GM), SNR for white matter (WM), their contrast-to-noise ratio (WM-to-GM CNR), detected number of CMIs were evaluated. 3D Cube FLAIR plus HyperSense showed a dramatically increased scores of uniformity, artifact, degree of lesion displacement, and overall image quality compared to 2D T2WI FLAIR. Meanwhile, it exhibited similar SNRwm and SNRgm, but a higher WM-to-GM contrast-to-noise ratio compared with 2D T2WI FLAIR. Furthermore, the scanning time of 3D Cube FLAIR plus HyperSense and 2D T2WI FLAIR were both set as 2.5 minutes. Encouragingly, 244 CMIs were detected by 3D Cube FLAIR plus HyperSense, which was higher compared to 2D T2WI FLAIR (106 detected CMIs). 3D Cube FLAIR plus HyperSense compressed sensing is superior to 2D T2WI FLAIR scanning regarding image quality, spatial resolution, detection rate for CMIs; meanwhile, it does not increase the scanning time. These findings may contribute to early detection and treatment of stroke.

Brain magnetic resonance imaging and cognitive alterations after ablation in patients with atrial fibrillation

Catheter ablation is an important non-pharmacological intervention for atrial fibrillation (AF), but its effect on the incidence of asymptomatic cerebral emboli and long-term effects on cognitive function remain unknown. We prospectively enrolled 101 patients who underwent AF ablation. Brain magnetic resonance imaging (MRI) (72 patients) and neuropsychological assessments (66 patients) were performed 1–3 days (baseline) and 6 months after ablation. Immediately after ablation, diffusion-weighted MRI and 3-dimensional double inversion recovery (3D-DIR) detected embolic microinfarctions in 63 patients (87.5%) and 62 patients (86.1%), respectively. After 6 months, DIR lesions disappeared in 41 patients. Microbleeds (MBs) increased by 17%, and 65% of the de novo MBs were exactly at the same location as the microinfarctions. Average Mini-Mental State Examination scores improved from 27.9 ± 2.4 to 28.5 ± 1.7 (p = 0.037), and detailed neuropsychological assessment scores showed improvement in memory, constructional, and frontal lobe functions. Ejection fraction, left atrial volume index and brain natriuretic peptide level improved from baseline to 3–6 months after ablation. Despite incidental microemboli, cognitive function was preserved 6 months after ablation.

Micro-MRI improves the accuracy of clinical diagnosis in cerebral small vessel disease

Even with postmortem pathological examination, only limited information is provided of the foci of in vivo clinical information. Cerebral small vessel disease, which is associated with ageing, dementia and stroke, highlights the difficulty in arriving at a definitive diagnosis of the lesions detected on in vivo radiological examination. We performed a radiological−pathological comparative study using ex vivo MRI to examine small cerebral lesions. Four patients with small vessel disease lesions detected on in vivo MRI were studied. Exact pathological findings of in vivo MRI-detected lesions were revealed. The ischaemic lesion after 17 days from onset showed positivity for peroxiredoxin, cluster of differentiation 204 and glial fibrillary acidic protein, indicating sterile inflammation and neuroprotective reaction. Cortical microinfarcts beneath the cortical superficial siderosis were associated with inflammation from the superficial layer in a patient with cerebral amyloid angiopathy; in this patient, a bilinear track-like appearance of the cortical superficial siderosis on the ex vivo MRI was compatible with iron deposition on the pia matter and within cortical layers II–III. An in vivo MRI-detected cerebral microbleed was revealed to be heterogeneous. An in vivo MRI-detected cerebral microbleed was revealed to be a venous angioma. Furthermore, a neuropathologically confirmed embolic cerebral microbleed was firstly detected using this method. Our results suggest that in vivo MRI-detected lobar cerebral microbleeds can be caused by non-cerebral amyloid angiopathy aetiologies, such as microembolism and venous angioma. Venous angioma and embolic microbleeds may mimic cerebral amyloid angiopathy markers on in vivo MRI. To clarify the clinical importance of these lesions, we should investigate their rate and frequency in a large cohort of healthy individuals and patients with cardiac risk factors. Thus, we provide evidence that ex vivo micro-MRI improves the clinical diagnosis of small vessel diseases.

Long-term neurobehavioral correlates of brain cortical microinfarcts in a memory clinic cohort in Singapore

BACKGROUND

Cortical cerebral microinfarcts are a small vessel disease biomarker underlying cognitive impairment and dementia. However, it is unknown whether cortical cerebral microinfarcts are associated with neuropsychiatric disturbances, and whether its effects are independent of conventional small vessel disease markers.

AIMS

We investigated the associations of cortical cerebral microinfarcts burden with incidence and progression of neuropsychiatric subsyndromes in a memory clinic cohort of elderly in Singapore.

METHODS

In this prospective cohort, 496 subjects underwent detailed neuropsychological and clinical assessments, 3T brain MRI, and Neuropsychiatric Inventory assessment at baseline and two years later. Cortical cerebral microinfarcts and other small vessel disease markers, including white matter hyperintensities, lacunes, and microbleeds, were graded according to established criteria. Neuropsychiatric symptoms (NPS) were clustered into subsyndromes of hyperactivity, psychosis, affective, and apathy following prior findings. Functional decline was determined using the clinical dementia rating (CDR) scale.

RESULTS

The presence of multiple cortical cerebral microinfarcts (≥2) was associated with higher total NPS scores (β = 4.19, 95% CI = 2.81-5.58, p < 0.001), particularly hyperactivity (β = 2.01, 95% CI = 1.30-2.71, p < 0.01) and apathy (β = 1.42, 95% CI = 0.65-2.18, p < 0.01) at baseline. Between baseline and year-2, multiple cortical cerebral microinfarcts were associated with accelerated progression in total NPS scores (β = 0.29, 95% CI = 0.06-0.53, p = 0.015), driven by hyperactivity (β = 0.45, 95% CI = 0.17-0.72, p < 0.01). Subjects with multiple cortical cerebral microinfarcts also had a faster functional decline, as measured with the CDR-sum-of-boxes scores, when accompanied with progression (β = 0.31, 95% CI = 0.11-0.51, p < 0.01) or hyperactivity in total NPS (β = 0.34, 95% CI = 0.13-0.56, p < 0.01).

CONCLUSION

Cortical cerebral microinfarcts are associated with incidence and progression of geriatric neurobehavioral disturbances, independent of conventional small vessel disease markers. The impact of incident cortical cerebral microinfarcts on neurocognitive and neuropsychiatric trajectories warrants further investigations.

Evaluation of cortical superficial siderosis in patients with cognitive dysfunction using 3D FLAIR and 3D DIR

OBJECTIVES

Our aim was to evaluate the detectability of cortical superficial siderosis (cSS) by 3D FLAIR and 3D DIR images in comparison with the SWI images in patients with cognitive dysfunction.

METHODS

We studied 246 patients with cognitive dysfunction (144 women, 102 men; mean age: 75.5 ± 7.53 years) who visited a memory clinic at our hospital and underwent MR examinations at 3 T. Specifically, 16 patients with Alzheimer disease (AD) (n = 11) and AD with cerebrovascular disease (n = 5) manifested cSS based on SWI. Each set of MR images (3D FLAIR and 3D DIR) was reviewed by two reviewers separately for the detection of sulcal hyperintensity that suggested cSS.

RESULTS

SWI detected a greater number of cSS sulci than 3D DIR and 3D FLAIR. The sensitivity and specificity for the detection of sulcal hyperintensity were the same between 3D FLAIR and 3D DIR (87.5%/100%). However, 3D DIR detected a greater number of cSS sulci than 3D FLAIR (p = .005).

CONCLUSIONS

Our study showed that 3D DIR and 3D FLAIR can detect sulcal hyperintensity related to cSS although they are less sensitive to cSS lesions than SWI.

KEY POINTS

• 3D FLAIR and 3D DIR can show sulcal signal abnormalities related to cSS in patients with cognitive dysfunction. • 3D FLAIR and 3D DIR detect sulcal hyperintensity of cSS, although they are less sensitive to cSS than SWI. • Signal alterations due to cSS are more detectable in 3D DIR than in 3D FLAIR.

Association between cortical microinfarcts and total small vessel disease burden in cerebral amyloid angiopathy on 3-Tesla magnetic resonance imaging

BACKGROUND AND PURPOSE

Cortical microinfarcts (CMIs) are frequently found in the brains of patients with advanced cerebral amyloid angiopathy (CAA) at autopsy. The small vessel disease (SVD) score for CAA (i.e., the CAA-SVD score) has been proposed to evaluate the severity of CAA-associated vasculopathic changes by a combination of magnetic resonance imaging (MRI) markers. The aim of this study was to examine the association between total CAA-SVD score and features of CMIs on in vivo 3-Tesla MRI.

METHODS

Eighty patients with probable CAA were retrospectively analyzed. Lobar cerebral microbleeds, cortical superficial siderosis, enlargement of perivascular space in the centrum semiovale and white matter hyperintensity were collectively assessed, and the total CAA-SVD score was calculated. The presence of CMI was also examined.

RESULTS

Of the 80 patients, 13 (16.25%) had CMIs. CMIs were detected more frequently in the parietal and occipital lobes. A positive correlation was found between total CAA-SVD score and prevalence of CMI (ρ = 0.943; p = 0.005). Total CAA-SVD score was significantly higher in patients with CMIs than in those without (p = 0.009). In a multivariable logistic regression analysis, the presence of CMIs was significantly associated with total CAA-SVD score (odds ratio 2.318 [95% confidence interval 1.228-4.376]; p = 0.01, per each additional point).

CONCLUSIONS

The presence of CMIs with a high CAA-SVD score could be an indicator of more severe amyloid-associated vasculopathic changes in patients with probable CAA.

Impairment of intermediate somatosensory function in corticobasal syndrome

Corticobasal syndrome (CBS) is characterized by unilateral atrophy of the brain. New diagnostic criteria for CBS include intermediate somatosensory dysfunction. Here, we aimed to carefully examine intermediate somatosensory function to identify tests which can assess impairment in CBS patients. Using voxel-based morphometry (VBM), we also aimed to show the anatomical bases of these impairments. Subjects included 14 patients diagnosed with CBS and 14 patients with Parkinson's disease (PD). Patients were evaluated using intermediate somatosensory tests and neuropsychological assessments. VBM was used to analyze differences in gray matter volumes between CBS and PD patients. In the PD group, no tests showed a significant difference between the dominant-side onset and the non-dominant-side onset. In the CBS group, all tests showed worse scores on the affected side. For detecting intermediate somatosensory dysfunction in CBS, two tests are recommended: tactile object naming and 2-point discrimination. VBM analysis showed that the volume of the left post- and pre-central gyrus, and both sides of the supplementary motor area were significantly decreased in the CBS group compared to the PD group. Although CBS remains untreatable, early and correct diagnosis is possible by performing close examination of intermediate somatosensory function.

Cortical Microinfarcts Detected by 3-Tesla Magnetic Resonance Imaging

Background and Purpose—

Cortical microinfarcts (CMIs) are small ischemic lesions found in cerebral amyloid angiopathy (CAA) and embolic stroke. This study aimed to differentiate CMIs caused by CAA from those caused by microembolisms, using 3-Tesla magnetic resonance imaging.

Methods—

We retrospectively investigated 70 patients with at least 1 cortical infarct <10 mm on 3-dimensional double inversion recovery imaging. Of the 70 patients, 43 had an embolic stroke history (Emboli-G) while 27 had CAA-group. We compared the size, number, location, and distribution of CMIs between groups and designed a radiological score for differentiation based on the comparisons.

Results—

CAA-group showed significantly more lesions <5 mm, which were restricted to the cortex ( P <0.01). Cortical lesion number was significantly higher in Emboli-G than in CAA-group (4 versus 2; P <0.01). Lesions in CAA-group and Emboli-G were disproportionately located in the occipital lobe ( P <0.01) and frontal or parietal lobe ( P =0.04), respectively. In radiological scoring, ≥3 points strongly predicted microembolism (sensitivity, 63%; specificity, 92%) or CAA (sensitivity, 63%; specificity, 91%). The areas under the receiver operating characteristic curve were 0.85 and 0.87 for microembolism and CAA, respectively.

Conclusions—

Characteristics of CMIs on 3T-magnetic resonance imaging may differentiate CMIs due to CAA from those due to microembolisms.

Cortical Cerebral Microinfarcts on 3T Magnetic Resonance Imaging in Patients With Carotid Artery Stenosis

Background and Purpose- Carotid artery stenosis is common in the elderly and contributes to cognitive impairment and dementia. Cortical cerebral microinfarcts (CMIs) play an important role in vascular cognitive impairment and dementia. We aimed to investigate the association between CMIs on 3T magnetic resonance imaging and clinical and radiological features, including plaque morphology, and cognitive function in patients with carotid stenosis. Methods- Eighty-nine patients with >30% carotid stenosis on ultrasound were prospectively enrolled, and underwent brain and carotid artery magnetic resonance imaging. CMIs were rated according to predetermined criteria based on 3D-double inversion recovery and fluid-attenuated inversion recovery images. Results- CMIs were identified in 26 patients (29%; median number 0, range 0-9). Poisson regression models adjusted for age and sex revealed that CMIs were associated with intraplaque hemorrhage (rate ratio, 1.95; 95% CI, 1.26-3.18), lacunar infarcts (rate ratio, 1.54; 95% CI, 1.00-2.44), and cortical infarcts (rate ratio, 3.22; 95% CI, 2.20-5.00). These associations were also observed in asymptomatic patients (n=64). Of 81 patients with unilateral carotid stenosis, the prevalence and number of CMIs were significantly higher in the hemisphere ipsilateral to the carotid stenosis than in the contralateral hemisphere ( P=0.005 and P<0.001, respectively). The presence of CMIs was associated with poor cognitive function. Conclusions- Our results indicate that vulnerable carotid plaque increases the risk of CMIs and subsequent cognitive impairment. Carotid atherosclerosis could be a potential therapeutic target for cognitive impairment.

Cerebral microbleeds: hearing through the silence-a narrative review

OBJECTIVE

The term cerebral microbleed (CMB) refers to lesions documented as unexpected findings during computed tomography or magnetic resonance imaging examination of the brain. Initially, a CMB was thought to represent hemosiderin-laden macrophages marking an area of a tiny hemorrhage. Recently, histopathologic studies have shown that the structure of a CMB can be variable. To aid in dealing with this finding and judging its clinical significance, this review addresses important aspects of a CMB, including the definition, prevalence, and incidence in various populations, end-organ damage, associated conditions, and whether any action or treatment by the clinician might be indicated.

METHODS

PubMed Medline, EMBASE, BIOSIS, Current Contents, and Derwent Drug Files databases were searched for the keywords "microbleeds-detection-damage", "silent bleeds", "microbleeds", or "silent bleeds AND hemophilia" from 2011-2016. References of retrieved articles were also reviewed and included if applicable.

RESULTS

The published data are found primarily in the imaging literature and focus on diagnostic techniques. Some publications address relationships with diverse, co-existing clinical conditions and implications for treatment, especially in stroke, intracranial hemorrhage, and antithrombotic therapy.

CONCLUSIONS

It is critical for non-radiologist clinicians (primary care, internists, neurologists, hematologists) to be aware of the potential importance of the finding of a CMB, and the fact that these lesions are not always truly silent or without important clinical consequences. As additional studies appear, clinicians may be able to "hear" more clearly through the silence of the CMB and understand potential clinical implications in patients.

3D double inversion recovery MR imaging: Clinical applications and usefulness in a wide spectrum of central nervous system diseases

Double inversion recovery (DIR) imaging provides two inversion pulses that attenuate signals from cerebrospinal fluid and normal white matter. This review was undertaken to describe the principle of the DIR sequence, the clinical applications of 3D DIR in various central nervous system diseases and the clinical benefits of the 3D DIR compared with those of other MR sequences. 3D DIR imaging provides better lesion conspicuity and topography than other MR techniques. It is particularly useful for diagnosing the following disease entities: cortical and subcortical abnormalities such as multiple sclerosis, cortical microinfarcts and cortical development anomalies; sulcal abnormalities such as meningitis and subacute/chronic subarachnoid hemorrhage; and optic neuritis caused by multiple sclerosis or neuromyelitis optica.

Cortical Cerebral Microinfarcts on 3 Tesla MRI in Patients with Vascular Cognitive Impairment

BACKGROUND

Cerebral microinfarcts (CMIs) are small ischemic lesions that are a common neuropathological finding in patients with stroke or dementia. CMIs in the cortex can now be detected in vivo on 3 Tesla MRI.

OBJECTIVE

To determine the occurrence of CMIs and associated clinical features in patients with possible vascular cognitive impairment (VCI).

METHOD

182 memory-clinic patients (mean age 71.4±10.6, 55% male) with vascular injury on brain MRI (i.e., possible VCI) underwent a standardized work-up including 3 Tesla MRI and cognitive assessment. A control group consisted of 70 cognitively normal subjects (mean age 70.6±4.7, 60% male). Cortical CMIs and other neuroimaging markers of vascular brain injury were rated according to established criteria.

RESULT

Occurrence of CMIs was higher (20%) in patients compared to controls (10%). Among patients, the presence of CMIs was associated with male sex, history of stroke, infarcts, and white matter hyperintensities. CMI presence was also associated with a diagnosis of vascular dementia and reduced performance in multiple cognitive domains.

CONCLUSION

CMIs on 3 Tesla MRI are common in patients with possible VCI and co-occur with imaging markers of small and large vessel disease, likely reflecting a heterogeneous etiology. CMIs are associated with worse cognitive performance, independent of other markers of vascular brain injury.

Comparative Analysis of Cortical Microinfarcts and Microbleeds using 3.0-Tesla Postmortem Magnetic Resonance Images and Histopathology

Microvascular lesions including cortical microinfarctions (CMIs) and cerebral lobar microbleeds (CMBs) are usually caused by cerebral amyloid angiopathy (CAA) in the elderly and are correlated with cognitive decline. However, their radiological-histopathological coincidence has not been revealed systematically with widely used 3-Tesla (3T) magnetic resonance imaging (MRI). The purpose of the present study is to delineate the histopathological background corresponding to MR images of these lesions. We examined formalin-fixed 10-mm thick coronal brain blocks from 10 CAA patients (five were also diagnosed with Alzheimer's disease, three with dementia with Lewy bodies, and two with CAA only) with dementia and six non CAA patients with neurodegenerative disease. Using 3T MRI, both 3D-fluid attenuated inversion recovery (FLAIR) and 3D-double inversion recovery (DIR) were examined to identify CMIs, and T2* and susceptibility-weighted images (SWI) were examined to identify CMBs. These blocks were subsequently examined histologically and immunohistochemically. In CAA patients, 48 CMIs and 6 lobar CMBs were invariably observed in close proximity to degenerated Aβ-positive blood vessels. Moreover, 16 CMIs (33%) of 48 were detected with postmortem MRI, but none were seen when the lesion size was smaller than 1 mm. In contrast, only 1 undeniable CMI was founded with MRI and histopathology in 6 non CAA patients. Small, cortical high-intensity lesions seen on 3D-FLAIR and 3D-DIR images likely represent CMIs, and low-intensity lesions in T2* and SWI correspond to CMBs with in vivo MRI. Furthermore, a close association between amyloid-laden vessels and these microvascular lesions indicated the contribution of CAA to their pathogenesis.

The significant effects of cerebral microbleeds on cognitive dysfunction: An updated meta-analysis

Objective

Accumulated data suggests that cerebral microbleeds (CMBs) play an important role in the decline of cognitive function, but the results remain inconsistent. In the current study, we aimed to investigate the association between CMBs and cognitive function, as well as the various effects of CMBs on different domains of cognition.

Methods

We searched through the databases of PubMed, Embase, Cochrane Library, and ScienceDirect. After a consistency test, the publication bias was evaluated and a sensitivity analysis was performed with combined odds ratios (OR) and standardized mean difference (SMD) of CMBs.

Results

A meta-analysis of 25 studies with 9343 participants total was conducted. Patients with CMBs had higher incidence of cognitive impairment (OR:3.5410; 95% confidence interval [CI] [2.2979, 5.4567], p<0.05) and lower scores of cognitive functions (SMD: -0.2700 [-0.4267, -0.1133], p<0.05 in Mini-Mental State Examination [MMSE] group and -0.4869 [-0.8902, -0.0818], p<0.05 in Montreal Cognitive Assessment [MoCA] group). Our results also indicated that patients with CMBs had obvious decline in cognitive functions, for instance, orientation (SMD: -0.9565 [-1.7260, -0.1869], p<0.05), attention and calculation (SMD: -1.1518 [-1.9553, -0.3484], p<0.05) and delayed recall (SMD: -0.5527 [-1.1043, -0.0011], p = 0.05).

Conclusions

Our data suggested that CMBs might be an important risk factor for cognitive dysfunction, especially in the domains of orientation, attention and calculation and delayed recall functions. Prospective cohort studies with further investigations will be needed in larger samples.

Detection, risk factors, and functional consequences of cerebral microinfarcts

Cerebral microinfarcts are small lesions that are presumed to be ischaemic. Despite the small size of these lesions, affected individuals can have hundreds to thousands of cerebral microinfarcts, which cause measurable disruption to structural brain connections, and are associated with dementia that is independent of Alzheimer's disease pathology or larger infarcts (ie, lacunar infarcts, and large cortical and non-lacunar subcortical infarcts). Substantial progress has been made with regard to understanding risk factors and functional consequences of cerebral microinfarcts, partly driven by new in-vivo detection methods and the development of animal models that closely mimic multiple aspects of cerebral microinfarcts in human beings. Evidence from these advances suggests that cerebral microinfarcts can be manifestations of both small vessel and large vessel disease, that cerebral microinfarcts are independently associated with cognitive impairment, and that these lesions are likely to cause damage to brain structure and function that extends beyond their actual lesion boundaries. Criteria for the identification of cerebral microinfarcts with in-vivo MRI are provided to support further studies of the association between these lesions and cerebrovascular disease and dementia.