Amyloid angiopathy causing widespread miliary haemorrhages within the brain evident on MRI

Structural imaging measures of brain aging

During the course of normal aging, biological changes occur in the brain that are associated with changes in cognitive ability. This review presents data from neuroimaging studies of primarily "normal" or healthy brain aging. As such, we focus on research in unimpaired or nondemented older adults, but also include findings from lifespan studies that include younger and middle aged individuals as well as from populations with prodromal or clinically symptomatic disease such as cerebrovascular or Alzheimer's disease. This review predominantly addresses structural MRI biomarkers, such as volumetric or thickness measures from anatomical images, and measures of white matter injury and integrity respectively from FLAIR or DTI, and includes complementary data from PET and cognitive or clinical testing as appropriate. The findings reveal highly consistent age-related differences in brain structure, particularly frontal lobe and medial temporal regions that are also accompanied by age-related differences in frontal and medial temporal lobe mediated cognitive abilities. Newer findings also suggest that degeneration of specific white matter tracts such as those passing through the genu and splenium of the corpus callosum may also be related to age-related differences in cognitive performance. Interpretation of these findings, however, must be tempered by the fact that comorbid diseases such as cerebrovascular and Alzheimer's disease also increase in prevalence with advancing age. As such, this review discusses challenges related to interpretation of current theories of cognitive aging in light of the common occurrence of these later-life diseases. Understanding the differences between "Normal" and "Healthy" brain aging and identifying potential modifiable risk factors for brain aging is critical to inform potential treatments to stall or reverse the effects of brain aging and possibly extend cognitive health for our aging society.

Intracerebral hematoma extends via perivascular spaces and perineurium

Intracerebral hemorrhage (ICH) is a devastating disorder associated with high morbidity and mortality. ICH results in the formation of hematoma that affects not only the primary site of injury but also the remote regions. In fact, hematoma can extend via perivascular spaces (also called Virchow-Robin spaces, VRS) and perineurium in an animal model of ICH. In the present study, we used magnetic resonance imaging (MRI) with susceptibility-weighted imaging (SWI) to investigate the characteristics of the perivascular and perineural extensions of hematomas in patients with ICH. A total of 20 ICH patients without secondary subarachnoid and secondary intraventricular hemorrhages were recruited. Brain MRI scans, including SWI, T1, and T2-weighted images, were performed between 17 h to 7 days after the onset of ICH. MRI with SWI revealed that paramagnetic substances spread along the VRS or the perineurium. Such distribution could cause the formation of cerebral microbleeds (CMBs). However, the distribution of remote hemorrhagic lesions varied, depending on the size and location of the original hematoma. The unenhanced CT scans of the 20 patients did not show any hyperdensity around the blood vessels and nerve tracts outside the hematoma. These results indicate the perivascular and perineural extensions of hematomas in patients with ICH, which is formed by the leakage of the original hematoma via the VRS or perineurium. We also provide a new explanation for the series of pathological processes involved in ICH, including the remote effects of hematoma and the formation of CMBs in patients with ICH.

Antithrombotic drug uses and deep intracerebral hemorrhages in stroke patients with deep cerebral microbleeds

BACKGROUND

It has been suggested that antiplatelet or anticoagulant drugs elevate the rate of intracerebral hemorrhage (ICH) in patients with cerebral microbleeds (MBs). To investigate the mechanism by which antiplatelet drugs or warfarin may contribute to deep ICH occurrences in patients with deep MBs, we prospectively analyzed deep ICH occurrences in 807 consecutive patients (351 females and 456 males; mean age ± standard deviation 69.8 ± 12.0 years) who were admitted to our hospital with strokes.

METHODS

Occurrence-free rate curves were generated using the Kaplan-Meier method; deep ICH occurrence-free rates were compared using the log-rank test. The follow-up period was 0.5 to 71 months (mean ± standard deviation 31.6 ± 22.2 months).

RESULTS

In patients with deep MBs, the rates (1.0%/year; 6 ICHs in 180 patients) of deep ICH occurrence associated with antiplatelet drugs were not significantly greater than that without the drugs (1.0%/year; 6 ICHs in 167 patients; P = .977). The incidence of deep ICHs associated with warfarin use was not significantly greater than that without warfarin use.

CONCLUSIONS

Multivariate analysis revealed that the use of antiplatelet drugs or warfarin did not significantly influence the occurrence of deep ICH in patients with deep MBs. Antiplatelet drugs or warfarin did not significantly elevate the rate of deep ICHs in stroke patients with pre-existing deep MBs.

The difference in location between traumatic cerebral microbleeds and microangiopathic microbleeds associated with stroke

BACKGROUND AND PURPOSE

Microbleeds (MBs) are low-intensity spots on gradient echo T2*-weighted MRI frequently associated with cerebral microangiopathies resulting in stroke. MBs can also be caused by cerebral axonal injuries. We compared the location of MBs associated with cerebral microangiopathies with those associated with trauma.

METHODS

T2*-weighted MRI identified traumatic MBs (t-MBs) in 23 (6 females; 38.7 ± 25.8 years old) of the 312 patients with head trauma consecutively admitted to our hospital between March 2003 and March 2009. We prospectively examined for the presence of microangiopathic MBs (m-MBs) in the 131 patients (59 females; 65.2 ± 9.2 years old) admitted consecutively for stroke (May -December 2004) as controls.

RESULTS

We identified a total of 145 t-MBs and 504 m-MBs. t-MBs were frequently located in the mid portion of the subcortical area of the cerebrum, above the corpus callosum in axial slices, and were absent from the basal ganglia. In contrast, m-MBs were frequently located within the basal ganglia or thalamus.

CONCLUSION

There are substantial differences in locations of MB development in trauma patients in comparison to stroke patients.

Hypoperfusion and ischemia in cerebral amyloid angiopathy documented by 99mTc-ECD brain perfusion SPECT

Cerebral amyloid angiopathy (CAA) is known to be an important cause of spontaneous cortical-subcortical intracranial hemorrhage in normotensive older persons. CAA can also manifest as leukoencephalopathy, brain atrophy, and ischemia secondary to hypoperfusion. Our goal was to verify cerebral hypoperfusion in patients with CAA using (99m)Tc-ethylcysteinate dimer ((99m)Tc-ECD) brain perfusion SPECT.

METHODS

A total of 11 patients (5 men and 6 women; age range, 58-78 y; mean age +/- SD, 70.0 +/- 7.0 y) with clinically and radiologically established probable CAA who underwent (99m)Tc-ECD SPECT were included. (99m)Tc-ECD SPECT scans were also obtained from 13 age-matched healthy control subjects (7 men and 6 women; age range, 60-79 y; mean age +/- SD, 66.7 +/- 6.4 y) for comparison. The relative regional cerebral blood flow values obtained for patients and controls were compared using software.

RESULTS

Compared with controls, patients with probable CAA showed hypoperfusion in the inferior parietal lobule of both parietal lobes (Brodmann area [BA] 40), middle temporal gyrus of the left temporal lobe (BA 39), postcentral gyrus of the right parietal lobe, superior temporal gyrus of the right temporal lobe (BA 22), superior temporal gyrus of the right frontal lobe (BA 10), inferior temporal gyrus of the left temporal lobe (BA 20), and both caudate bodies (P < 0.0001, t = 4.65).

CONCLUSION

Patients with probable CAA had significantly decreased cerebral perfusion and may be at risk for leukoencephalopathy, atrophy, and ischemia.

The number of microbleeds on gradient T2*-weighted magnetic resonance image at the onset of intracerebral hemorrhage

OBJECTIVE

Deep intracerebral hematoma (ICH) is frequently associated with microbleed (MB) arising from degenerated MB. Increased numbers of MB are correlated with increased age, and we examined a possible relationship between MB number and ICH onset in younger patients.

METHODS

Excluding patients with ICH and a history of ICH, we examined the number of MB and other risk factors in 195 patients with deep ICH (97 male, 98 female) consecutively admitted to our hospital. The patients were equally divided into 3 subgroups according to age (groups A, B, and C). Odds ratios were estimated from logistic regression analyses.

RESULTS

The number (percentage) of MB in group A (< or =60 years old, n = 64) 5.0 +/- 9.6 (65.6%) was less than group B (61-69 years old, n = 63) 6.6 +/- 9.1 (79.4%) or group C (> or =70 years old, n = 68) 6.0 +/- 7.0 (86.8%). Multivariate analyses demonstrated that MB greater than or equal to 3 was significantly associated with higher age in group A versus B (odds ratio: 2.3; 95% confidence interval: 1.01-5.3; P = .046) and in group A versus C (odds ratio: 2.6; 95% confidence interval: 1.1-6.2; P =.030).

CONCLUSIONS

Our findings suggest that risk factors for the development of ICH may differ with age, and younger patients with deep ICH have fewer MB.

Dynamics of dot-like hemosiderin spots on T2*-weighted MRIs associated with stroke recurrence

BACKGROUND AND PURPOSE

Dot-like low-intensity spots (dot-like hemosiderin spots: dotHSs) on gradient echo T2*-weighted (-w) brain magnetic resonance imaging (MRIs) are frequently associated with cerebral small vessel disease (SVD), including deep intracerebral hemorrhages and lacunar infarctions. This study investigated how numbers of newly appeared dotHSs contribute to recurrent SVD.

METHODS

We prospectively analyzed numbers of newly appeared dotHSs in 12 patients with prior SVD (8 males, 4 females; mean 67.6 +/- 10.7 years old) readmitted with recurring SVD between October 2001 and March 2003. Numbers of appeared dotHSs per year were counted on T2*-w MRI scans after SVD recurrence and compared to previous MRIs. Seventy-one outpatients (35 males, 36 females; mean 64.3 +/- 9.6 years old) with histories of intracerebral hemorrhages (ICH) that came to the hospital during the study period served as controls. The hazard ratio (HR) for recurrence was estimated from a multivariate logistic regression model, using the number of appeared dotHSs (per year) and other risk factors.

RESULTS

Multivariate analyses revealed that an elevated rate of recurrence was found in patients with substantial numbers of appeared dotHSs (>or=5/year) (HR, 7.34; P= 0.0008). We also analyzed factors associated with the numbers of appeared dotHSs. A number of appeared dotHSs (>or=5/year) was significantly and independently associated with the initial number of dotHSs (>or=10) on T2*-w MRIs following the first SVD (HR, 18.6; P= 0.0001).

CONCLUSIONS

Though a small sample size limited the power of our analyses, our findings suggest that a number of newly appeared dotHSs may be associated with SVD recurrence.

Neuroradiological findings in vascular dementia

INTRODUCTION

There are multiple diagnostic criteria for vascular dementia (VaD) that may define different populations. Utilizing the criteria of the National Institute of Neurological Disorders and Stroke and Association Internationale pour la Recherche et l'Enseignement en Neurosciences (NINDS-AIREN) has provided improved consistency in the diagnosis of VaD. The criteria include a table listing brain imaging lesions associated with VaD.

METHODS

The different neuroradiological aspects of the criteria are reviewed based on the imaging data from an ongoing large-scale clinical trial testing a new treatment for VaD. The NINDS-AIREN criteria were applied by a centralized imaging rater to determine eligibility for enrollment in 1,202 patients using brain CT or MRI.

RESULTS

Based on the above data set, the neuroradiological features that are associated with VaD and that can result from cerebral small-vessel disease with extensive leukoencephalopathy or lacunae (basal ganglia or frontal white matter), or may be the consequence of single strategically located infarcts or multiple infarcts in large-vessel territories, are illustrated. These features may also be the consequence of global cerebral hypoperfusion, intracerebral hemorrhage, or other mechanisms such as genetically determined arteriopathies.

CONCLUSION

Neuroimaging confirmation of cerebrovascular disease in VaD provides information about the topography and severity of vascular lesions. Neuroimaging may also assist with the differential diagnosis of dementia associated with normal pressure hydrocephalus, chronic subdural hematoma, arteriovenous malformation or tumoral diseases.

Hematoma size in deep intracerebral hemorrhage and its correlation with dot-like hemosiderin spots on gradient echo T2*-weighted MRI

BACKGROUND AND PURPOSE

Dot-like low intensity spots (dot-like hemosiderin spots: dotHSs) on gradient echo T2*-weighted MRI have been histologically diagnosed to represent old cerebral microbleeds associated with microangiopathies. They have also been correlated to the fragility of small vessels and the tendency to bleed. Therefore, a substantial number of dotHSs might be associated with a large-sized, deep intracerebral hematoma (ICH). On the other hand, dotHSs may reflect old microbleeds that did not enlarge to symptomatic size.

METHODS

To investigate how dotHSs are related to the size (maximal diameter) of primary deep ICH, we analyzed the diameter and the number of dotHSs in 151 patients with deep ICH not associated with subarachnoid hemorrhage or intraventricular hemorrhage (75 males and 76 females, age ranged from 37 to 90 [65.7 +/- 11.3 years old] who were consecutively admitted to Hakodate Municipal Hospital. The hazard ratio (HR) for a maximal diameter of deep ICH < or =2 cm was estimated, using the number of dotHSs and risk factors for stroke.

RESULTS

The number of dotHSs associated with the diameter < or =2 cm was 9.2 +/- 11.5, significantly larger than that with the diameter > or =2 cm (4.7 +/- 7.0, P= .012). Multivariate analysis revealed that a maximal diameter of deep ICH of < or =2 cm was found in patients with dotHS (HR, 3.7; 95% confidence interval [CI], 1.4-10.1; P= .009).

CONCLUSION

Though small sample size limited the power of our analyses, these findings suggest that the number of dotHSs may be associated with a small diameter of deep ICH.

Dot-Like Hemosiderin Deposition on T2*-Weighted MR Imaging Associated with Nonhypertensive Intracerebral Hemorrhage

BACKGROUND AND PURPOSE

Microangiopathy, a disorder often related to hypertension, is an important cause of deep intracerebral hematoma (ICH). The microangiopathy is associated with dot-like low-intensity spots (a dot-like hemosiderin spot: dotHS) on gradient-echo T2*-weighted MR images that have been histologically diagnosed as old microbleeds. The locations of dotHS are consistent with deep ICH.

METHODS

To investigate how dotHS or other risk factors contribute to nonhypertensive deep ICH, the number and location of dotHSs, as well as other risk factors were examined in 213 deep ICH patients (106 males, 107 females, age: 37-94 (65.8 +/- 11.2) years) consecutively admitted to Hakodate Municipal Hospital. Patients were divided into two subgroups according to the presence or absence of hypertension. DotHSs were also divided into deep and subcortical dotHS and investigated independently. Odds ratios (ORs) were estimated from logistic regression analyses. Furthermore, nonhypertensive ICH patients were compared with nonhypertensive healthy volunteers matched for age and sex.

RESULTS

No risk factors were identified in the 31 nonhypertensive deep ICH patients that differed from those found in the 182 hypertensive deep ICH patients. Deep dotHS > or = 1 (OR: 25.5; 95% CI: 4.76-137; P = .0002), subcortical dotHS > or = 1 (OR: 9.0; 95% CI: 1.79-44.9; P = .046), diabetes mellitus (OR: 9.0; 95% CI: 1.53-52.3; P = .015), and smoking (OR, 9.6; 95% CI; 1.8-49.8, P = .007) significantly elevated the risk of nonhypertensive ICH, compared to the healthy volunteers.

CONCLUSIONS

Our findings suggest that deep and subcortical dotHSs may be risk factors for the development of non-hypertensive deep ICH.

Dotlike hemosiderin spots on T2*-weighted magnetic resonance imaging as a predictor of stroke recurrence: a prospective study

Object. Microangiopathy associated with hypertension is a notable cause of cerebral small vessel disease (SVD), including deep intracerebral hemorrhage (ICH) and lacunar infarct. Dotlike low-intensity spots (dotlike hemosiderin spots: dotHSs) on T2*-weighted magnetic resonance (MR) images have been histologically diagnosed as old cerebral microbleeds associated with lipohyalinosis, amyloid angiopathy, or other microangiopathies and located in deep or subcortical regions. The aim of this study was to determine whether dotHSs indicate the severity of microangiopathy, and if so, whether large numbers of deep dotHSs are associated with SVD recurrence.

Methods. The authors prospectively analyzed the number of dotHSs in 337 patients—191 men and 146 women with a mean age of 66 ± 10.4 years (range 37–94 years)—with SVD (199 ICHs and 138 lacunar infarcts) who had been consecutively admitted to Hakodate Municipal Hospital. The follow-up period was 3.5 to 42 months (22.5 ± 13.1 months). Patients were divided into two groups based on the recurrence. The hazard ratio (HR) for recurrence was estimated based on the Cox proportional hazard model by using the number of deep and subcortical dotHSs as well as other factors. Of 337 patients, 20 were readmitted with recurrence. Results of a multivariate analysis revealed an elevated rate of recurrence in patients with many subcortical dotHSs (≥ 5, HR 4.36, p = 0.0019) or a history of ICH (HR 3.82, p = 0.014). A trend toward a positive correlation (Pearson correlation coefficient 0.548, p < 0.0001) was found between the number of deep and subcortical dotHSs.

Conclusions. Although a small sample size limited the power of analyses, the findings indicate that a large number of subcortical dotHSs may predict SVD recurrence.

Cerebral amyloid angiopathy-related hemorrhage. Interaction of APOE epsilon2 with putative clinical risk factors

BACKGROUND AND PURPOSE

Current evidence suggests that the apolipoprotein E (APOE for gene; apoE for protein) epsilon4 allele predisposes to cerebral amyloid angiopathy (CAA) whereas epsilon2 is associated with CAA-related hemorrhage (CAAH). The clinical risk factors for other forms of intracranial hemorrhage are a less-frequent feature of CAAH. In this study we examined potential clinical risk factors in patients with CAAH and assessed these with respect to APOE genotype.

METHODS

Thirty-six patients were identified with a pathological diagnosis of CAAH. Clinical notes were reviewed to document age of hemorrhage onset, history of dementia, antiplatelet/anticoagulant medication, hypertension, minor head trauma, or transient neurological events. In a review of reported cases of CAAH, the frequency of these clinical features was also recorded. APOE genotypes were determined with use of polymerase chain reaction techniques.

RESULTS

There were 24 women and 12 men; the mean age was 70.3 years. One third (n=12) had been taking antiplatelet medication, and a similar number were demented. Nine patients were hypertensive, and 4 had a history of recent minor head trauma. The relative frequency of each of these clinical features was similar to that in previous reports. Forty-four percent (16 of 36) possessed an epsilon2 allele. Antiplatelet or anticoagulant medication, hypertension, or minor head trauma were significantly more frequent antecedents of CAAH in epsilon2 carriers than in non-epsilon2 carriers (81% versus 35%, P=0.008), antiplatelet/anticoagulant medication in particular (P=0.038).

CONCLUSIONS

Our findings suggest that antiplatelet or anticoagulant medication, hypertension, or minor head trauma are most likely to precipitate cerebral hemorrhage in patients with CAA who are also epsilon2 carriers. This may result from isoform-specific effects of apoE on the structure of amyloid-laden blood vessel walls.