Journal of neuroimaging : official journal of the American Society of Neuroimaging
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Intravenous recombinant tissue plasminogen activator (rt-PA) is the only therapy of proven value for patients with acute ischemic stroke (AIS). Controversy exists with regard to the prognostic significance of early computed tomography (CT) changes in patients receiving rt-PA for AIS. The authors retrospectively reviewed all cases of AIS who received intravenous rt-PA for AIS in University of South Alabama hospitals between January 1996 and May 1999. ⋯ The frequency of specific findings were as follows: SE in 13 patients (36%), LGWD in 12 patients (33%), PH in 9 patients (25%), HMCA in 4 patients (11%), and IRS in 3 patients (8%) patients. There was no statistically significant association between the occurrence of these imaging findings and subsequent functional outcome after thrombolysis. The data suggest that the presence of subtle acute CT changes in AIS patients is not predictive of clinical outcome following administration of rt-PA as per National Institute of Neurological Disorders and Stroke protocol.
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There has been limited data on the frequency of microembolic signals in patients with middle cerebral artery (MCA) stenosis, especially during the acute phase of stroke. Using transcranial Doppler, the authors prospectively monitored the MCA segments distal to stenosis in 4 groups of patients for 30 minutes: (1) symptomatic patients with acute ischemic stroke and MCA stenosis, (2) asymptomatic group patients with asymptomatic MCA stenosis, (3) control patients with acute ischemic stroke of undetermined etiology, and (4) normal people. A total of 60 patients completed the study. ⋯ Among 20 patients in the symptomatic group, microembolic signals were detected in 3 patients (15%). The number of emboli ranged from 1 to 6 per 30 minutes. This is the first report of the presence of microembolic signals in acute stroke patients with MCA stenosis.
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The purpose of this study was to investigate cerebral arteriolar vasoreactivity function in preeclampsia. Preeclamptic (n = 26) and healthy pregnant (n = 22) women underwent transcranial Doppler sonography of the middle cerebral artery at rest and after 60 seconds of hyperventilation (HV). Systolic, diastolic, and mean blood flow velocities were recorded. ⋯ No difference could be detected in percentage change of middle cerebral artery blood flow velocities after HV between the two groups. There is no evidence of a small-vessel vasoconstriction among preeclamptic patients. The role of vasoconstriction of the large cerebral arteries and vasodilation of the resistance arterioles, as well as a combination of these 2 pathomechanisms, in determining cerebral blood flow in preeclampsia and eclampsia should be investigated in further studies.
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The objective of this study was to examine cerebral hemodynamics changes during hypothermic circulatory arrest (HCA) with and without retrograde cerebral perfusion (RCP). Thirteen colony-bred hound dogs were placed on cardiopulmonary bypass (CPB) and cooled to 18 degrees C. Five dogs underwent 2 hours of HCA without RCP and 8 with RCP. ⋯ During hypothermic circulatory arrest, RCP provides CBFV in the MCA comparable to MCA CBFV during CPB. HCA dogs without RCP showed immediate hyperemia on reperfusion. The decreased CBFV and increased PI at 1 hour after postarrest CPB could be an indicator of progressive ischemic injury due to the increased intracranial pressure despite the implementation of RCP.
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Regression of symptomatic intracranial atherostenosis is not known to be a common occurrence. In this case, delay of basilar reconstruction by endovascular means permitted serial angiographic assessment of plaque change. The use of high-dose atorvastatin over a 2-week period was associated with marked angiographic improvement. Medical programs of plaque stabilization may provide adjunctive benefit in patients with symptomatic intracranial disease.