Elsevier

The Lancet Neurology

Volume 6, Issue 7, July 2007, Pages 611-619
The Lancet Neurology

Review
Silent brain infarcts: a systematic review

https://doi.org/10.1016/S1474-4422(07)70170-9Get rights and content

Summary

As the availability and quality of imaging techniques improve, doctors are identifying more patients with no history of transient ischaemic attack or stroke in whom imaging shows brain infarcts. Until recently, little was known about the relevance of these lesions. In this systematic review, we give an overview of the frequency, causes, and consequences of MRI-defined silent brain infarcts, which are detected in 20% of healthy elderly people and up to 50% of patients in selected series. Most infarcts are lacunes, of which hypertensive small-vessel disease is thought to be the main cause. Although silent infarcts, by definition, lack clinically overt stroke-like symptoms, they are associated with subtle deficits in physical and cognitive function that commonly go unnoticed. Moreover, the presence of silent infarcts more than doubles the risk of subsequent stroke and dementia. Future studies will have to show whether screening and treating high-risk patients can effectively reduce the risk of further infarcts, stroke, and dementia.

Introduction

The symptoms and signs of transient ischemic attack or stroke have long defined cerebrovascular disease of the brain. However, the results of neuropathological studies in highly selected populations have shown that vascular disease manifesting as infarcts can result in injury to the brain in the absence of transient ischemic attack or stroke.1 The development of sophisticated brain-imaging techniques, initially with CT and subsequently with MRI, has enabled similar observations to be made in groups of patients and in healthy people and has forced a rethink of how to define cerebrovascular disease. In this review, we concentrate on one imaging modality (MRI) and one finding that is indicative of brain vascular disease (infarct) in selected patients and otherwise healthy people without a history of transient ischemic attack or stroke to explain the imaging findings. We present an overview of the frequency of these MRI-defined silent brain infarcts, their risk factors, and their consequences. Because they are common and associated with adverse health outcomes, these brain infarcts, which have often been considered as benign accompaniments to ageing, demand greater attention from those trying to control the deleterious effects of vascular disease in the brain.

Section snippets

Search strategy and selection criteria

Articles dating from 1966 to November 2006 were identified through searches of PubMed with the following terms: “silent brain infarcts”, “silent cerebral infarction”, “silent ischaemic lesions”, and “silent lacunes”. We limited searches to adult populations and papers written in English. The PubMed searches identified 313 articles in total. We also searched in the reference lists of relevant publications for further studies, resulting in another 34 articles. We restricted our systematic review

Detection

Infarcts are visible as focal lesions with roughly the same intensity as cerebrospinal fluid on both CT and MRI (figure 1). The sensitivity to detect infarcts is better for MRI compared with CT because of the improvements in MRI techniques with stronger field magnets, thinner slices, and different pulse sequences. This greater sensitivity is particularly true for small lesions located in the basal ganglia, which are often visible only on T2-weighted MRI scans. Studies using CT to detect silent

Conclusion

Silent brain infarcts are common not only in selected patients but also in the general population of elderly people; they are far more common than stroke, both with respect to prevalence and incidence. Cardiovascular risk factors known to increase the risk of stroke are also associated with silent brain infarcts, with hypertension being, by far, the strongest modifiable risk factor identified to date. Therefore, silent brain infarcts might differ from symptomatic infarcts only with respect to

References (152)

  • T Kawamura et al.

    Soluble adhesion molecules and C-reactive protein in the progression of silent cerebral infarction in patients with type 2 diabetes mellitus

    Metabolism

    (2006)
  • F Anan et al.

    Hyperhomocysteinemia is a significant risk factor for silent cerebral infarction in patients with chronic renal failure undergoing hemodialysis

    Metabolism

    (2006)
  • NL Cantelmo et al.

    Cerebral microembolism and ischemic changes associated with carotid endarterectomy

    J Vasc Surg

    (1998)
  • G Madycki et al.

    Carotid plaque texture analysis can predict the incidence of silent brain infarcts among patients undergoing carotid endarterectomy

    Eur J Vasc Endovasc Surg

    (2006)
  • CM Fisher

    Lacunes: small, deep cerebral infarcts

    Neurology

    (1965)
  • H Bokura et al.

    Distinguishing silent lacunar infarction from enlarged Virchow–Robin spaces: a magnetic resonance imaging and pathological study

    J Neurol

    (1998)
  • CA Jungreis et al.

    Normal perivascular spaces mimicking lacunar infarction: MR imaging

    Radiology

    (1998)
  • BH Braffman et al.

    Brain MR: pathologic correlation with gross and histopathology. 1: lacunar infarction and Virchow–Robin spaces

    Am J Roentgenol

    (1988)
  • T Revesz et al.

    Pathological findings correlated with magnetic resonance imaging in subcortical arteriosclerotic encephalopathy (Binswanger's disease)

    J Neurol Neurosurg Psychiatry

    (1989)
  • L White et al.

    Cerebrovascular pathology and dementia in autopsied Honolulu–Asia Aging Study participants

    Ann N Y Acad Sci

    (2002)
  • VJ Howard et al.

    High prevalence of stroke symptoms among persons without a diagnosis of stroke or transient ischemic attack in a general population: the REasons for Geographic And Racial Differences in Stroke (REGARDS) study

    Arch Intern Med

    (2006)
  • A Ylikoski et al.

    White matter hyperintensities on MRI in the neurologically nondiseased elderly: analysis of cohorts of consecutive subjects aged 55 to 85 years living at home

    Stroke

    (1995)
  • TR Price et al.

    Silent brain infarction on magnetic resonance imaging and neurological abnormalities in community-dwelling older adults

    Stroke

    (1997)
  • G Howard et al.

    Cigarette smoking and other risk factors for silent cerebral infarction in the general population

    Stroke

    (1998)
  • SE Vermeer et al.

    Prevalence and risk factors of silent brain infarcts in the population-based Rotterdam Scan study

    Stroke

    (2002)
  • K Kohara et al.

    MTHFR gene polymorphism as a risk factor for silent brain infarcts and white matter lesions in the Japanese general population: the NILS-LSA study

    Stroke

    (2003)
  • WP Schmidt et al.

    Functional and cognitive consequences of silent stroke discovered using brain magnetic resonance imaging in an elderly population

    J Am Geriatr Soc

    (2004)
  • R Schmidt et al.

    C-reactive protein, carotid atherosclerosis, and cerebral small-vessel disease. Results of the Austrian Stroke Prevention Study

    Stroke

    (2006)
  • ML Bots et al.

    Prevalence of stroke in the general population: the Rotterdam Study

    Stroke

    (1996)
  • MB Mittelmark et al.

    Prevalence of cardiovascular diseases among older adults: the Cardiovascular Health Study

    Am J Epidemiol

    (1993)
  • A Shinkawa et al.

    Silent cerebral infarction in a community-based autopsy series in Japan: the Hisayama Study

    Stroke

    (1995)
  • S Kobayashi et al.

    Subcortical silent brain infarction as a risk factor for clinical stroke

    Stroke

    (1997)
  • T Uehara et al.

    Risk factors for silent cerebral infarcts in subcortical white matter and basal ganglia

    Stroke

    (1999)
  • SC Lee et al.

    Prevalence and risk factors of silent cerebral infarction in apparently normal adults

    Hypertension

    (2000)
  • T Matsui et al.

    Elevated plasma homocysteine levels and risk of silent brain infarction in elderly people

    Stroke

    (2001)
  • S Maeshima et al.

    Silent cerebral infarction and cognitive function in middle-aged neurologically healthy subjects

    Acta Neurol Scand

    (2002)
  • SR Waldstein et al.

    Stress-induced blood pressure reactivity and silent cerebrovascular disease

    Stroke

    (2004)
  • HM Kwon et al.

    Metabolic syndrome as an independent risk factor of silent brain infarction in healthy people

    Stroke

    (2006)
  • WT Longstreth et al.

    Lacunar infarcts defined by magnetic resonance imaging of 3660 elderly people: the Cardiovascular Health Study

    Arch Neurol

    (1998)
  • LB Goldstein et al.

    Primary prevention of ischemic stroke: a statement for healthcare professionals from the Stroke Council of the American Heart Association

    Stroke

    (2001)
  • EA Vogels et al.

    Sex differences in cardiovascular disease: are women with low socioeconomic status at high risk?

    Br J Gen Pract

    (1999)
  • J Herlitz et al.

    Is there a gender difference in aetiology of chest pain and symptoms associated with acute myocardial infarction?

    Eur J Emerg Med

    (1999)
  • JM Holroyd-Leduc et al.

    Sex differences and similarities in the management and outcome of stroke patients

    Stroke

    (2000)
  • S Ramani et al.

    Gender differences in the treatment of cerebrovascular disease

    J Am Geriatr Soc

    (2000)
  • T Adachi et al.

    Frequency and pathogenesis of silent subcortical brain infarction in acute first-ever ischemic stroke

    Intern Med

    (2002)
  • K Uekita et al.

    Cervical and intracranial atherosclerosis and silent brain infarction in Japanese patients with coronary artery disease

    Cerebrovasc Dis

    (2003)
  • JLP Giele et al.

    Silent brain infarcts in patients with manifest vascular disease

    Stroke

    (2004)
  • M Hara et al.

    Silent cortical strokes associated with atrial fibrillation

    Clin Cardiol

    (1995)
  • H Hougaku et al.

    Asymptomatic carotid lesions and silent cerebral infarction

    Stroke

    (1994)
  • K Kario et al.

    ‘Silent’ cerebral infarction is associated with hypercoagulability, endothelial cell damage, and high Lp(a) levels in elderly Japanese

    Arterioscler Thromb Vasc Biol

    (1996)
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