Diffuse axonal injury after traumatic cerebral microbleeds: an evaluation of imaging techniques

Previous neuropathological studies regarding traumatic brain injury have primarily focused on changes in large structures, for example, the clinical prognosis after cerebral contusion, intrace- rebral hematoma, and epidural and subdural hematoma. In fact, many smaller injuries can also lead to severe neurological disorders. For example, cerebral microbleeds result in the dysfunc- tion of adjacent neurons and the disassociation between cortex and subcortical structures. These tiny changes cannot be adequately visualized on CT or conventional MRI. In contrast, gradient echo sequence-based susceptibility-weighted imaging is very sensitive to blood metabolites and microbleeds, and can be used to evaluate traumatic cerebral microbleeds with high sensitivity and accuracy. Cerebral microbleed can be considered as an important imaging marker for dif- fuse axonal injury with potential relevance for prognosis. For this reason, based on experimental and clinical studies, this study reviews the role of imaging data showing traumatic cerebral microbleeds in the evaluation of cerebral neuronal injury and neurofunctional loss.

Microbleeds in fronto-subcortical circuits are predictive of dementia conversion in patients with vascular cognitive impairment but no dementia

Cerebral small vessel disease（CSVD） is a common etiology of vascular cognitive impairment with no dementia（V-CIND）. Studies have revealed that cerebral microbleeds（CMBs）, a feature of CSVD, contribute to cognitive impairment. However, the association between CMBs and dementia conversion in individuals with V-CIND is still unclear. Here, we analyzed the predictive role of CMBs in the conversion from V-CIND to dementia in CSVD patients. We recruited and prospectively assessed 85 patients with CSVD and V-CIND. V-CIND was evaluated using a series of comprehensive neuropsychological scales, including the Chinese version of the Montreal Cognitive Assessment and the Clinical Dementia Rating. MRI assessments were used to quantify lacunar infarcts, white matter hyperintensities, CMBs, and medial temporal lobe atrophy. Eighty-two of the 85 patients completed the assessment for dementia conversion at a 1-year follow-up assessment. Multivariate logistic regression analyses were conducted to examine independent clinical and MRI variables associated with dementia conversion. Twenty-four patients（29.3%） had converted to dementia at the 1-year follow-up, and these individuals had significantly more CMBs in the fronto-subcortical circuits. Multivariate logistic regression analyses revealed that the patients with CMBs in the fronto-subcortical circuits（odds ratio = 4.4; 95% confidence interval： 1.602-12.081, P = 0.004） and 5 or more CMBs overall（odds ratio = 17.6, 95% confidence interval： 3.23-95.84, P = 0.001） had a significantly increased risk of dementia at the 1-year follow-up. These findings indicate that CMBs in the fronto-subcortical circuits may be predictive of dementia conversion in CSVD patients with V-CIND, and thus extend the clinical significance of CMBs.

A Transfer Learning-Based Approach to Detect Cerebral Microbleeds

Cerebral microbleeds are small chronic vascular diseases that occur because of irregularities in the cerebrum vessels.Individuals and elderly people with brain injury and dementia can have small microbleeds in their brains.A recent study has shown that cerebral microbleeds could be remarkably risky in terms of life and can be riskier for patients with dementia.In this study,we proposed an efficient approach to automatically identify microbleeds by reducing the false positives in openly available susceptibility-weighted imaging(SWI)data samples.The proposed structure comprises two different pretrained convolutional models with four stages.These stages include(i)skull removal and augmentation,(ii)making clusters of data samples using the k-mean classifier,(iii)reduction of false positives for efficient performance,and(iv)transfer-learning classification.The proposed technique was assessed using the SWI dataset available for 20 subjects.For our findings,we attained an accuracy of 97.26%with a 1.8%false-positive rate using data augmentation on the AlexNet transfer learning model and a 1.1%false-positive rate with 97.89%accuracy for the ResNet 50 model with data augmentation approaches.The results show that our models outperformed the existing approach for the detection of microbleeds.

Cerebral Microbleeds Identified by Susceptibility-Weighted Imaging in Two Cases of Fabry Disease without Neurological Symptoms

Cerebrovascular disease is one of the fatal causes of Fabry disease (FD). Brain magnetic resonance imaging findings typically show lacunar infarcts in young patients with FD, but brain hemorrhages in FD are rarely reported. We report two cases of FD focusing on cerebral microbleeds (CMBs). Susceptibility-weighted imaging (SWI) and T2*-weighted imaging reveal several lobar and deep CMBs in two patients with no medical history of stroke symptoms, hypertension, and anticoagulant/antiplatelet treatment. SWI can detect a greater number of CMBs than T2*-weighted imaging. Thus, SWI is an excellent tool for identifying underlying CMBs in FD.

An Efficient False-Positive Reduction System for Cerebral Microbleeds Detection

Cerebral Microbleeds(CMBs)are microhemorrhages caused by certain abnormalities of brain vessels.CMBs can be found in people with Traumatic Brain Injury(TBI),Alzheimer’s disease,and in old individuals having a brain injury.Current research reveals that CMBs can be highly dangerous for individuals having dementia and stroke.The CMBs seriously impact individuals’life which makes it crucial to recognize the CMBs in its initial phase to stop deterioration and to assist individuals to have a normal life.The existing work report good results but often ignores false-positive’s perspective for this research area.In this paper,an efficient approach is presented to detect CMBs from the Susceptibility Weighted Images(SWI).The proposed framework consists of four main phases(i)making clusters of brain Magnetic Resonance Imaging(MRI)using k-mean classifier(ii)reduce false positives for better classification results(iii)discriminative feature extraction specific to CMBs(iv)classification using a five layers convolutional neural network(CNN).The proposed method is evaluated on a public dataset available for 20 subjects.The proposed system shows an accuracy of 98.9%and a 1.1%false-positive rate value.The results show the superiority of the proposed work as compared to existing states of the art methods.

Elevated Pulse Pressure Is a Risk Factor for Cerebral Microbleeds. A Single Center Case-Control Study

Recent developments in brain magnetic resonance imaging using advanced Susceptibility Weighted Imaging (SWI) have significantly increased the detection and prevalence of Cerebral Microbleeds (CMBs). Here, we aimed to explore the association between Pulse Pressure (PP) and CMBs. Having been implicated in various arteriopathies, we hypothesized that elevated PP could also be a risk for CMBs. A retrospective case-control study was conducted from August 2021 to September 2022 at Zhongnan Hospital of Wuhan University China. Extracted data were analyzed in SPSS. Chi-square test, binary logistic regression, and Spearman’s correlation analysis were conducted.104 patients were analyzed. Univariate analysis showed no significant association between PP and CMBs, OR 1.65 (95% CI: 0.737 - 3.694;p > 0.05), while DBP and alcohol consumption were significant, ORs 2.956 (95% CI: 1.249 - 6.997, p < 0.05) and 2.525 (95% CI: 1.062 - 6.002, p < 0.05) respectively. Multivariate analysis, showed that PP was significantly associated with CMBs, OR 3.194 (95% CI: 1.024 - 9.964, p < 0.05) in combination with SBP, DBP, gender, age, smoking and alcohol consumption. Taken together, the study showed that elevated PP is associated with CMB, but is not an independent risk factor for CMBs.

High Blood Pressure Increases the Risk of Cerebral Microbleeds in Hypertensive Individuals

Introduction: Hypertension is the leading preventable risk factor for major cardiovascular diseases worldwide. Recently, compelling evidence has emerged associating hypertension with cerebral microbleeds (CMBs), which are subclinical hemorrhages in the brain resulting from structural abnormalities in the small vessels that supply the brain. In addition to overall elevated blood pressure (BP), elevation in individual parameters such as systolic BP, diastolic BP, pulse pressure and mean arterial pressure could also individually be important risk factors for CMBs. This study aimed to assess the association between CMBs and blood pressure, and assess blood pressure parameters that could be possible risk factors for CMB. Methods: A retrospective case-control study was conducted from August 2021 to September 2022 on patients who underwent MRI due to primary complaints of limb disorders, loss of consciousness, persistent dizziness, and intermittent headaches. The patients were divided according to MRI results into 52 cases (those who had CMBs) and 52 controls (those who had no CMBs). Extracted data were analyzed in SPSS. Chi-square test, binary logistic regression, and Spearman’s correlation analysis were conducted. Results: In total, 104 cases and control patients were assessed, with mean (±SD) age 70.6 ± 8.56 vs 68.9 ± 8.93 years respectively (p > 0.05). CMB patients had more cases of stroke, hyperlipidemia and diabetes than non-CMB patients. Systolic blood pressure (SBP), diastolic blood pressure, pulse pressure (PP) and mean arterial pressure (MAP) were all considerably raised in CMB patients than non-CMBs patients. Blood pressure grades were positively correlated with the severity of CMBs (r = 0.22;p = 0.044). Logistic regression analysis showed that SBP and MAP were independent risk factors for CMBs (age and sex adjusted odds ratio = 1.420;95% CI: 1.030 - 1.851, and 1.310;95% CI: 1.011 - 1.631 respectively). Conclusions: In summary, this study found that hypertension was positively correlated with CMBs severity, and that SBP and MAP are independent risk factors for CMBs in patients with hypertension.

Ischaemic Stroke Complicating Infective Endocarditis: Microbleeds Are the Diagnostic Clue

Introduction: Ischemic strokes represent a classic complication of infective endocarditis (IE) and are most often related to the fragmentation of valvular vegetation. In most cases, they occur in the Sylvian territory and are related to Staphylococcus aureus. MRI can demonstrate, in addition to the AVCI image, cerebral microbleeds (CMBs) that are very suggestive of the diagnosis. We present the case of a patient who presented an ischemic stroke occurring in the context of infective endocarditis. Observation: A 32-year-old woman with no previous medical history initially presented with acute febrile headache, two weeks later she developed right hemiplegia with aphasia in the context of fever. Her general examination revealed lesions on the soles of her feet, in the form of nodules, infected in places, suggestive of Janeway nodules (characteristic of IE). The brain MRI showed an ischemic stroke in the Sylvian territory, with the presence of multiple microbleeds on the magnetic susceptibility sequences. The biological examination showed a severe inflammatory syndrome;the transthoracic echocardiography (TTE) confirmed the presence of vegetation on the aortic valve;and the blood cultures showed a Staphylococcus aureus. Antibiotic therapy was started, and the patient was transferred to the cardiology department. Discussion: Our observation has a double interest. The first is clinical due to the presence of plantar nodules (Janeway’s nodules) that are characteristic of IE which should orientate the diagnosis before the installation of the stroke, and the second is radiological and linked to the discovery of microbleeds. Their presence is increasingly reported in the literature, but their pathophysiology is not yet very clear. Conclusion: Stroke is the most frequent extracardiac complication during IE. The presence of microbleeds contributes to early diagnosis, especially in asymptomatic forms.

Original article ：Cerebral microbleeds prevalence, distribution and risk factors in northeast population without preceding large-area stroke

Background Cerebral microbleeds （CMBs） occur frequently in patients suspected of cerebrovascular disease and they are the principle radiographic findings in patients with sub-clinical neurological impairment. The objective of this study was to assess the prevalence, distribution, severity and associated clinical features of CMBs in a prospective hospital patient based cohort undergoing brain MRI for suspected cerebrovascular disease, excluding cases with known intracranial hemorrhage or prior large-area stroke. Methods The study population consisted of 447 patients who were evaluated with T2＊-gradient echo sequences to detect the CMBs lesion number, location, and their association with white matter hyperintensities and clinical parameters, including blood pressure. Results CMB lesions were presented in 95 of the 447 patients （21.3%）. The distribution of CMBs was 43.95% cortical, 19.77% thalamic, 14.41% in the brainstem, 11.58% cerebellar, 6.21% periventricular white matter, 5.64% involving the basal ganglia regions, and 0.28% involving the hippocampus. There was a statistically significant association between the presence of CMBs and advancing age （adjusted OR 2.082, P 〈0.01）, the severity of hypertension （adjusted OR 2.208 P 〈0.01）. Also there was a statistically significant （P 〈0.01） correlation between the presence of CMBs and the severity of hypertension and white matter lesions. Conclusions CMBs occur frequently in patients with no prior large-area stroke who were referred for brain MRI for suspected cerebrovascular disease. The severity of CMBs correlates with the severity of hypertension and the presence of cerebral white matter changes detected by MRI.

Relationship of cerebral microbleeds to inflammatory marker levels

Aim: The purpose of this study is to investigate the incidence, distribution and risk factors of cerebral microbleeds (CMBs) and the relation between CMBs and inflammation in ischemic cerebrovascular disease. Methods: Two hundred and one patients without acute infarction or transient ischemic attack were enrolled. The presence and number of CMB were assessed on susceptibility-weighted imaging. The traditional risk factors of CMB were recorded. Levels of high-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6), and matrix metalloproteinase-9 (MMP-9) were tested. Logistic regression analyses were used for multiple-factor analysis of risk factors of CMB. Results: Of the 201 patients, 49 (24.38%) had CMB. Multivariate logistic regression analyses showed that the age, the prevalence of hypertension, silent lacunar infarction, white matter lesion, Montreal Cognitive Assessment Score, the using rate of antithrombotic drugs and levels of hs-CRP, IL-6, MMP-9 were the risk factors for CMB. After adjustments for traditional risk factors, inflammatory marker levels remained to be associated with CMBs. The adjusted odd ratios of hs-CRP, IL-6 and MMP-9 were 1.745 (1.342-2.270), 1.223 (1.018-1.533) and 1.284 (1.082-1.423), respectively. Furthermore, inflammatory marker levels were the risk factor for deep or infratentorial CMBs and lobar CMBs. Conclusion: The age, prevalence of hypertension, silent lacunar infarction, white matter lesion, MoCA Score, the using rate of antithrombotic drugs and serum hs-CRP, IL-6, and MMP-9 levels were the independent risk factors for CMBs.

Reversible leukoencephalopathy with seizures:a case of severe high-altitude cerebral edema

Background Acute high-altitude illness(AHAI)refers to a series of syndromes including acute mountain sickness(AMS),high-altitude pulmonary edema(HAPE)and high-altitude cerebral edema(HACE).Among these,HACE is a severe and potentially life-threatening condition that can occur when individuals ascend to high altitudes.It is often characterized by ataxia,confusion,and altered mental status.Without appropriate treatment,HACE can rapidly progress to coma,but seizures are infrequent in occurrence.Case presentation Here,we report a severe HACE patient with coma and status epilepticus.The patient is a 23-year-old male who was visiting Lhasa for the first time.He initially experienced headaches and dizziness on the first day,and then he was found in coma with limb convulsions on the next day.Immediate medical attention was sought,and brain CT and MRI scans showed reversible white matter lesions,especially in the corpus callosum and subcortical white matter.Although the lesions disappeared on T1 and T2 sequences,microbleeds were observed on the SWI sequence.After treatment with tracheal intubation,glucocorticoids and hyperbaric oxygen,the cerebral edema has resolved and the clinical symptoms improved,the patient has no seizures anymore.Conclusions HACE typically follows AMS and poses a significant risk to life.Clinical manifestations mainly include ataxia,alterations of behavior,and impaired consciousness,with severe cases progressing to coma.Seizures,though rarely observed,may occur.Imaging shows reversible white matter lesions,with microbleeds being a significant and persistent imaging marker over time.Administration of glucocorticoids plays a crucial role in treatment.Despite experiencing seizures,this patient did not experienced any further episodes once his condition improved.

Hypertension-Induced Cerebral Small Vessel Disease Leading to Cognitive Impairment

Objective： Alzheimer＇s disease and vascular dementia are responsible for more than 80% of dementia cases. These two conditions share common risk factors including hypertension. Cerebral small vessel disease （CSVD） is strongly associated with both hypertension and cognitive impairment. In this review, we identify the pathophysiological changes in CSVD that are caused by hypertension and further explore the relationship between CSVD and cognitive impairment. Data Sources： We searched and scanned the PubMed database for recently published literatures up to December 2017. We used the keywords of＂hypertension＂, ＂cerebral small vessel disease＂, ＂＇white matter lesions＂, ＂enlarged perivascular spaces＂, ＂lacunar infarcts＂, ＂cerebral microbleeds＂, and ＂cognitive impairment＂ in the database of PubMed. Study Selection： Articles were obtained and reviewed to analyze the hypertension-induced pathophysiological changes that occur in CSVD and the correlation between CSVD and cognitive impairment. Results： In recent years, studies have demonstrated that hypertension-related changes （e.g., small vascular lesions, inflarnmator3, reactions, hypoperfusion, oxidative stress, damage to autoregulatory processes and the blood-brain barrier, and cerebral amyloid angiopathy） can occur over time in cerebral small vessels, potentially leading to lower cognitive function when blood pressure （BP） control is poor or lacking. Both isolated and co-occurrent CSVD can lead to cognitive deterioration, and this effect may be attributable to a dysfunction in either the cholinergic system or the functionality of cortical and subcortical tracts. Conclusions： We explore the currently available evidence about the hypertensive vasculopathy and inflammatory changes that occur in CSVD. Both are vital prognostic indicators of the development of cognitive impairment. Future studies should be performed to validate the relationship between BP levels and CSVD progression and between the nunabers, volumes, and anatomical locations of CSVD and cognitive impairment.