cerebral_microbleed

Cerebral microbleed

Clinically silent ischemic stroke and previous brain hemorrhages are a common finding on MR images of patients with primary intracerebral hemorrhage. They may therefore serve as evidence of diffuse microangiopathy with a possible increased risk for cerebral hemorrhage. 1).

MRI evidence of past microbleeds may be found even in neurologically normal elderly individuals and is related, but not restricted, to other indicators of small vessel disease. The predictive potential of this finding regarding the risk of intracerebral bleeding requires further investigation 2).

The prevalence of cerebral microbleeds is high.

Data support the hypothesis that strictly lobar microbleeds are related to cerebral amyloid angiopathy, whereas microbleeds in a deep or infratentorial location result from hypertensive or atherosclerotic microangiopathy 3).

Cerebral Microbleed Etiology.

Traumatic brain injury-induced cerebral microbleeds

They appear as small, hypointense lesions on T2-weighted images.

When cerebral microhemorrhages are diagnosed on MRI, conclusions regarding their significance and associated risks should be made based on the population examined. Further studies to characterize the associated risks of cerebral microhemorrhages in different stroke populations are needed to use this new imaging marker in therapeutic decisions 4).

Cerebral microbleeds might indicate a higher risk of future intracerebral hemorrhage and may be a marker of cerebral small-vessel disease and cerebral amyloid angiopathy. However, more prospective data are required in order to confirm these assumptions. Recommendations to guide antithrombotic treatment based on the detection of cerebral microbleeds are presently not justified 5).

Cordonnier et al., reviewed and critically appraised the published literature according to QUADAS, STARD and Cochrane principles. The selection criteria were met by 54 studies of 53 case series involving 9073 participants, 4432 of whom were people with cerebrovascular diseases. There were significant biases in many of the studies: variation in MRI magnet strength, flip angle, slice gap and slice thickness; inconsistent definitions of BMB size (23% did not define size at all, and of those that did 44% chose a diameter of < or =5 mm); only 30% included participants who were representative of the disease under study; and only 53% mentioned that BMB evaluation was blinded to other factors of interest. By pooling data from similar studies, we found that the prevalence of BMBs was 5% [95% confidence interval (CI) 4-6] in healthy adults, 34% (95% CI 31-36) in people with ischaemic stroke, and 60% (95% CI 57-64) in people with non-traumatic intracerebral haemorrhage (ICH). In the studies where a distinction could be made, BMBs were more prevalent among recurrent strokes than first-ever strokes: they affected 23% (95% CI 18-29) with first-ever ischaemic stroke but 44% (95% CI 34-54) with recurrent ischaemic stroke, and 52% (95% CI 47-56) with first-ever ICH but 83% (95% CI 71-90) with recurrent ICH. By pooling data that could be extracted from similar studies, it appears that BMBs are associated with hypertension (OR 3.9, 95% CI 2.4-6.4) and diabetes mellitus (OR 2.2, 95% CI 1.2-4.2) in otherwise healthy adults, and that they are associated with hypertension (OR 2.3, 95% CI 1.7-3.0) in adults with cerebrovascular diseases. The association with hypertension was robust in sensitivity analyses. There is a pressing need for better designed studies to assess the diagnostic utility of BMBs, disentangle the many likely influences on their occurrence, and determine their prognostic utility and whether they should influence treatment. They conclude by proposing criteria for ideal study design and reporting 6).

A total of 1847 patients with unruptured and ruptured intracranial aneurysm from January 2010 to November 2017 were included in this cross-sectional study. Their clinical records and images, including the preoperative presence of CMBs identified by T2-weighted gradient-recalled-echo sequence on magnetic resonance imaging (MRI) were evaluated. Univariate analysis and multivariate logistic regression were done to determine which parameters are independent factors for aneurysm rupture. The incubation period of CMBs related intracranial aneurysm rupture was also evaluated.

CMBs confirmed by MRI were present in 142 patients, with 7.7% incidence rate (142/1847). Of the total 142 patients with CMBs, 56 patients (including 17 ruptured anrueysms) received endovascular treatment, and other 86 consecutive patients who did not receive emobilization or surgery due to various reasons were followed for 3-49 months. The incidence of CMBs related intracranial aneurysm rupture was 27.9% (24/86) during the follow-up. The incubation period of CMBs related intracranial aneurysm rupture varies from 3 to 27 months (median month, 9.5 months). Multivariate analyses showed CMBs is significantly correlated with the intracranial aneurysm rupture (OR 1.6, 95%C.I. 1.1 to 2.4, P=0.010).

CMBs is independently associated with the intracranial aneurysm rupture. Patient with CMBs has the increased 60% risk of aneurysm rupture than those without 7).


1)
Offenbacher H, Fazekas F, Schmidt R, Koch M, Fazekas G, Kapeller P. MR of cerebral abnormalities concomitant with primary intracerebral hematomas. AJNR Am J Neuroradiol. 1996 Mar;17(3):573-8. PubMed PMID: 8881257.
2)
Roob G, Schmidt R, Kapeller P, Lechner A, Hartung HP, Fazekas F. MRI evidence of past cerebral microbleeds in a healthy elderly population. Neurology. 1999 Mar 23;52(5):991-4. PubMed PMID: 10102418.
3)
Vernooij MW, van der Lugt A, Ikram MA, Wielopolski PA, Niessen WJ, Hofman A, Krestin GP, Breteler MM. Prevalence and risk factors of cerebral microbleeds: the Rotterdam Scan Study. Neurology. 2008 Apr 1;70(14):1208-14. doi: 10.1212/01.wnl.0000307750.41970.d9. PubMed PMID: 18378884.
4)
Viswanathan A, Chabriat H. Cerebral microhemorrhage. Stroke. 2006 Feb;37(2):550-5. Review. PubMed PMID: 16397165.
5)
Koennecke HC. Cerebral microbleeds on MRI: prevalence, associations, and potential clinical implications. Neurology. 2006 Jan 24;66(2):165-71. Review. PubMed PMID: 16434647.
6)
Cordonnier C, Al-Shahi Salman R, Wardlaw J. Spontaneous brain microbleeds: systematic review, subgroup analyses and standards for study design and reporting. Brain. 2007 Aug;130(Pt 8):1988-2003. Review. PubMed PMID: 17322562.
7)
Zhang X, Yao ZQ, Karuna T, Duan CZ, Wang XM, Li XF, Yin JH, He XY, Guo SQ, Chen YC, Liu WC. Cerebral Microbleeds Could be Independently Associated with the Intracranial Aneurysm Rupture: A Cross-Sectional Population-Based Study. World Neurosurg. 2018 Apr 11. pii: S1878-8750(18)30734-4. doi: 10.1016/j.wneu.2018.04.018. [Epub ahead of print] PubMed PMID: 29654957.
  • cerebral_microbleed.txt
  • Last modified: 2021/04/08 13:22
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