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Chapter 13 - Cerebrovascular disease
- from Section 2 - Cerebrovascular disease
- Edited by Jonathan H. Gillard, University of Cambridge, Adam D. Waldman, Imperial College London, Peter B. Barker, The Johns Hopkins University School of Medicine
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- Book:
- Clinical MR Neuroimaging
- Published online:
- 05 March 2013
- Print publication:
- 26 November 2009, pp 169-172
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Summary
Introduction
Stroke is the third largest cause of death in Western countries. As the commonest form of long-term adult disability, it is a major consumer of health spending. Eighty percent of strokes are caused by ischemic infarcts and 20% by hemorrhages. Despite the magnitude of the problem, successful active treatment of ischemic stroke was almost non-existent until the mid 1990s. Medical management was predominantly prophylactic, particularly concentrated upon the control of hypertension. The role of diagnostic tests was limited to confirmation of stroke diagnosis, differentiation of infarct from hemorrhage, and identification of those entities that may present with stroke-like symptoms and signs (“pseudostroke”). Chronic subdural hematoma, slow-growing tumors, demyelination, and arteriovenous malformations are all potentially treatable lesions that may present as pseudostroke. As many as 20% of stroke-like presentations can be caused by entities other than stroke.[1]
Limitations of basic stroke-screening methods
The success of thrombolytic drugs, coupled with their potential adverse effects in some cases, highlights the need for tests that are highly sensitive and specific for diagnosis, and that provided information on which group of patients is most likely to respond to therapy. Tests that are sufficiently non-invasive for serial measurement of the effect of therapy are also required. Current diagnostic tools for the investigation of stroke have become increasingly sophisticated and non-invasive. The basic principle has been that when investigation has been clinically justified, the brain and the carotid vessels in the neck need to be imaged. The imaging modalities used vary according to those available at the imaging center. Computed tomography (CT) of the brain and duplex Doppler ultrasound of the carotid arteries was until recent years the mainstay of investigation. Magnetic resonance imaging (MRI) and MR angiography (MRA), or CT and CT angiography (CTA) performed with high-resolution multidetector CT machines are progressively replacing single-detector plain CT and ultrasound. Digital subtraction angiography (DSA) and its associated cost and morbidity are progressively being used only as a conduit to interventional procedures.
10 - Cerebrovascular disease: overview
- from SECTION 2 - CEREBROVASCULAR DISEASE
- Edited by Jonathan H. Gillard, University of Cambridge, Adam D. Waldman, Charing Cross Hospital, London, Peter B. Barker, The Johns Hopkins University
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- Book:
- Clinical MR Neuroimaging
- Published online:
- 07 December 2009
- Print publication:
- 02 December 2004, pp 163-167
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Summary
Background
Stroke is the third biggest cause of death in Western countries. As the commonest form of long-term adult disability it is a major consumer of health spending. Eighty percent of strokes are due to ischemic infarcts and 20% due to hemorrhages. Despite the magnitude of the problem successful active treatment of ischemic stroke was almost nonexistent until the mid-1990s. Medical management was predominantly prophylactic, particularly concentrated upon the control of hypertension. The role of diagnostic tests was limited to confirmation of stroke diagnosis, differentiation of infarct from hemorrhage and identification of those entities, which may present with stroke like symptoms and signs (”pseudostroke”). Chronic subdural hematoma, slow growing tumors, demyelination and arteriovenous malformations (AVM) are all potentially treatable lesions which may present as pseudostroke. As many as 20% of stroke like presentations can be due to entities other than stroke (Libman et al., 1995).
Thrombolysis in ischemic stroke
The catalyst for enormously renewed interest in ischemic stroke was the publication in 1995 of the first trial suggesting patient outcome benefit following active thrombolytic treatment in patients treated within 3 h of the onset of symptoms (National Institute of Neurological Disorders and Stroke rtPA Stroke Study Group, 1995). In 1999 a prospective randomised trial of intra-arterial pro-urokinase in patients with occluded middle cerebral arteries (MCA) showed patient outcome benefit when treatment was initiated between 3 and 6 h after the onset of the stroke symptoms (Furlan et al., 1999).
6 - Clinical use of standard MRI
- Edited by Stephen Davis, Marc Fisher, National Institute of Mental Health, Bethesda, Maryland, Steven Warach, National Institutes of Health, Baltimore
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- Book:
- Magnetic Resonance Imaging in Stroke
- Published online:
- 26 August 2009
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- 20 March 2003, pp 69-84
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Summary
The basic standard Magenetic Resonance Imaging (MRI) sequences which should be applied in screening for stroke are T1 and T2- weighted axial or sagittal scans through the whole brain. In hyperacute stroke MRA sequences provide valuable and accurate information in respect to the patency of the major intracranial vessels. The principal use for Magnetization Transfer Contrast (MTC) in the stroke context is in time of flight (TOF) MRA, where it suppresses background parenchymal signal, increasing the conspicuity of small vessels. Fluid Attenuated Inversion Recovery (FLAIR) is a routinely available technique which produces heavily T2-weighted images, at the same time nulling or completely subtracting the normally bright cerebrospinal fluid signal. Hyperacute parenchymal hemorrhage can be detected by MRI by utilizing one of the T2-weighted magnetic susceptibility sensitive sequences such as T2-weighted gradient echo (GE). Standard MRI sequences are extremely sensitive to the detection of acute, subacute and chronic infarcts.