ÎÎA noninvasive intracranial vascular study is strongly recommended
during the initial imaging evaluation of the acute stroke patient if
either intra-arterial fibrinolysis or mechanical thrombectomy is being
considered for management but should not delay IV rtPA if indicated
(I-A).
ÎÎIn IV fibrinolysis candidates, the brain imaging study should be
interpreted within 45 minutes of patient arrival in the ED by a
physician with expertise in reading CT and MRI studies of the brain
parenchyma (I-C).
ÎÎCT perfusion and MRI perfusion and diffusion imaging, including
measures of infarct core and penumbra, may be considered for the
selection of patients for acute reperfusion therapy beyond the time
windows for IV fibrinolysis (IIb-B).
Note: These techniques provide additional information that may improve diagnosis,
mechanism, and severity of ischemic stroke and allow more informed clinical decision
making.
ÎÎFrank hypodensity on non–contrast-enhanced CT may increase the risk
of hemorrhage with fibrinolysis and should be considered in treatment
decisions. If frank hypodensity involves more than one third of the
middle cerebral artery territory, IV rtPA treatment should be withheld
(III-A).
For patients with cerebral ischemic symptoms that have
resolved:
ÎÎNoninvasive imaging of the cervical vessels should be performed
routinely as part of the evaluation of patients with suspected TIAs (I-A).
ÎÎNoninvasive imaging by means of CT angiography or magnetic
resonance angiography of the intracranial vasculature is recommended
to exclude the presence of proximal intracranial stenosis and/or
occlusion (I-A) and should be obtained when knowledge of intracranial
steno-occlusive disease will alter management.
Note: Reliable diagnosis of the presence and degree of intracranial stenosis requires
the performance of catheter angiography to confirm abnormalities detected with
noninvasive testing.
ÎÎPatients with transient ischemic neurological symptoms should
undergo neuroimaging evaluation within 24 hours of symptom onset or
as soon as possible in patients with delayed presentations (I-B).
Note: MRI, including diffusion-weighted imaging, is the preferred brain diagnostic
imaging modality. If MRI is not available, head CT should be performed.
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