Nascent lobar microbleeds and stroke recurrences.

BACKGROUND: Lobar microbleeds (MBs) are occasionally visible on gradient-echo T2*-weighted (T2*-w) magnetic resonance imagings (MRIs) in patients with deep intracerebral hemorrhages (ICHs). This study investigated the contribution of nascent lobar MBs to occurrences of deep ICHs. METHODS: We prospectively analyzed nascent lobar MBs in patients admitted to our hospital who were treated with index strokes between April 2004 and November 2009. Numbers of nascent lobar MBs were counted on T2*-w MRI scans around 1 year after index strokes and compared with previous MRIs on admission. Deep ICH occurrence-free rate curves were generated by the Kaplan-Meier method using the log-rank test. The odds ratio (OR) for deep ICH occurrence was derived from a multivariate logistic regression model using nascent lobar MBs and risk factors. RESULTS: We investigated MRIs (interscan interval: 14.6 ± 5.9 months) of 508 patients (207 women, 68.9 ± 11.5 years), with a follow-up period of 44.1 ± 15.4 months. Repeated T2*-w MRIs demonstrated 157 nascent lobar MBs in 62 of 508 patients. The occurrence rate of deep ICHs (1.9% per year) was significantly higher in patients with nascent lobar MBs than in those without (.5% per year, P = .012). Multivariate analyses revealed that the rate of nascent lobar MBs was significantly elevated in patients with deep ICH-type stroke recurrences (OR: 3.85, P = .020), adjusted by the presence of hypertension, diabetes mellitus, use of antithrombotic drugs, severity of white matter lesions, age, and gender. CONCLUSIONS: Though a cohort study limited the power of analyses, our findings suggested that lobar MBs might be associated with deep ICH.

Nascent deep microbleeds and stroke recurrences.

BACKGROUND: Cerebral microbleeds (MBs) on gradient echo T2*-weighted magnetic resonance imaging (MRI) scans are associated with the severity of cerebral microangiopathies. This study investigated the contributions of nascent deep MBs to stroke recurrence. METHODS: We prospectively analyzed nascent deep MBs in patients admitted to our hospital who were treated for index strokes between April 2004 and November 2009. The number of nascent deep MBs was counted on T2*-weighted MRI scans around 1 year after the index strokes, and compared to previous MRIs on admission. Stroke recurrence-free rate curves were generated using the Kaplan-Meier method using the log-rank test. The odds ratio for nascent deep MBs was derived using a multivariate logistic regression model that was based on recurrent strokes and other risk factors. RESULTS: We evaluated the MRIs (interval between MRIs 14.6 ± 5.9 months) of 508 patients (207 women; 68.9 ± 11.5 years), with a follow-up period of 44.1 ± 15.4 months. Repeated T2*-weighted MRI scans revealed 256 nascent deep MBs in 116 of 508 patients. The incidence of deep intracerebral hemorrhage was significantly greater in patients with nascent deep MBs than those without (2.0% vs 0.4% per year, respectively; P < .0001). Multivariate analyses revealed that the rate of nascent deep MBs was significantly elevated in patients whose stroke recurrences took the form of deep intracerebral hemorrhages (odds ratio 5.41; P = .007), when adjusted for hypertension, preexisting MBs, and other risk factors. CONCLUSIONS: Our findings suggested that nascent deep MBs might be associated with stroke recurrence, in particular with deep intracerebral hemorrhage.

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.

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.

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.

[Study on hemosiderin deposition after intracerebral hemorrhage].

BACKGROUND AND PURPOSE: Hemosiderin degenerated from intracerebral hematoma (ICH) can be visualized as low intensity on gradient-echo T2*-weighted (T2*-w) MRI, which is sensitive for hemosiderin. We studied the factors associated with the hemosiderin deposition on T2*-w MRI after ICH. METHODS: We analyzed T2*-w MRIs in 72 outpatients with past ICH (46 males, 26 females, 28-89 (60.0 +/- 9.8) years old) consecutively came to our hospital. The odds ratio (OR) for the apparent thickness > or = 2.5 mm of low intensity surrounding ICH cavity was estimated, using the time after the onset of ICH (17 weeks - 26 years), and other factors. RESULTS: All of old ICHs were visible as low intensities on T2*-w MRI. Multivariate logistic regression analysis revealed that an elevated ratio of the apparent thickness > or = 2.5 mm of hemosiderin was found for the patients with time > or =5 years between T2*-w MRI and the onset (odds ratio (OR): 0.24, 95% confidence interval (CI): 0.06-0.99), intraventricular or subarachnoid hemorrhage related to ICH (OR: 0.16, 95% CI: 0.03-0.77), and the diameter of ICH > or =2 cm (OR: 33.7, 95% CI: 4.6-245). CONCLUSION: Though small sample size limited the power of analyses, our findings suggest that the amount of hemosiderin deposition after ICH may be associated with the time after the onset, intraventricular or subarachnoid hemorrhage related to ICH, and the diameter of ICH.

Identification of Respiratory Neurons Regenerating Axons into Peripheral Nerve Grafts in Adult Rats.

The present aimed to identify the origin of medullary and upper cervical respiratory neurons regenerating their axons into the peripheral nerve grafts in adult rats. We employed an antidromic activation technique and a retrograde horseradish peroxidase (HRP) tracing method for determining the origins of the regenerating axons. Autologous segments of the common peroneal nerve were successfully implanted ventrolaterally into the proximal cut end of the C2 spinal cord hemisection (n = 24). Two to 5 months after implantation, spontaneous multi-unit discharges were recorded in all grafts; respiratory-related discharges in 21 (87.5%) grafts; and non-respiratory discharges in 3 (12.5%) grafts. The respiratory discharge patterns were similar to those for normal respiratory efferent neurons in rats. After the recordings were completed, 5 of 182 respiratory units explored in the medullary ventral respiratory cell group (VRG) neurons were antidromically activated by electrical stimulation of the grafts (n = 15). The estimated axonal conduction velocities ranged from 5.6 to 7.4 (mean 6.7) m/s. Retrograde horseradish peroxidase (HRP) labelings applied to the distal cut end of the grafts (n = 13) revealed that HRP-labeled cells were located, predominantly ipsilaterally, in the brainstem up to 5-10 mm distant from the implanted site. Some HRP-labeled cells were observed in the region of the nucleus ambiguus where many respiratory neurons exist. These results demonstrate that peripheral nerve grafts implanted in the C2 segment can induce axonal regeneration of medullary VRG neurons conveying funcional efferent signals.