Skip to main content Accessibility help
×
Home
Hostname: page-component-99c86f546-zzcdp Total loading time: 0.366 Render date: 2021-11-27T18:32:53.293Z Has data issue: true Feature Flags: { "shouldUseShareProductTool": true, "shouldUseHypothesis": true, "isUnsiloEnabled": true, "metricsAbstractViews": false, "figures": true, "newCiteModal": false, "newCitedByModal": true, "newEcommerce": true, "newUsageEvents": true }

29 - Disappearing deficits and disappearing lesions: diffusion/perfusion MRI in transient ischemic attack and intra-arterial thrombolysis

from Part IX - Magnetic resonance imaging in clinical stroke

Published online by Cambridge University Press:  02 November 2009

Jeffrey L. Saver
Affiliation:
UCLA Stroke Center, Los Angeles, CA
Chelsea Kidwell
Affiliation:
UCLA Stroke Center, Los Angeles, CA
Pak H. Chan
Affiliation:
Stanford University, California
Get access

Summary

Introduction

The brain responds dynamically to ischemic insult. A brief period of focal ischemia may disrupt synaptic transmission and produce transient neurological deficits without causing permanent tissue injury. A somewhat more severe ischemic insult may sufficiently disrupt the cellular energetic state to impair maintenance of ionic gradients across cell membranes, producing cytotoxic edema. Early restoration of blood flow may permit cellular re-energization and restoration of ionic gradients, with edema resolution. However, some cells that initially restore membrane integrity experience a late, secondary stage of injury and delayed cell death. These findings, previously elucidated in animal models, have now been demonstrated for the first time in acute human brain ischemia by diffusion magnetic resonance imaging (MRI).

Standard brain imaging techniques, computed tomography (CT) and conventional MRI, are insensitive to these dynamic and regionally varying neural parenchymal responses to tissue ischemia. In contrast, the novel MRI technique of diffusion imaging permits visualization of these critical tissue processes, affording new insights into the physiopathology of human cerebral ischemia. We will here review recent diffusion MRI findings in two settings of transient cerebral ischemic insult in human patients: spontaneous transient ischemic attacks and thrombolysis induced cerebral reperfusion.

Transient ischemic attack

Transient ischemic attacks (TIAs) are defined as neurological symptoms due to focal cerebral ischemia that resolve completely within 24 hours. The 24 hour cutoff employed in this definition was first promulgated in the 1950s, based on limited data.

Type
Chapter
Information
Cerebrovascular Disease
22nd Princeton Conference
, pp. 353 - 370
Publisher: Cambridge University Press
Print publication year: 2002

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Send book to Kindle

To send this book to your Kindle, first ensure no-reply@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about sending to your Kindle.

Note you can select to send to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

Find out more about the Kindle Personal Document Service.

Available formats
×

Send book to Dropbox

To send content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about sending content to Dropbox.

Available formats
×

Send book to Google Drive

To send content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about sending content to Google Drive.

Available formats
×