Journal of neuroimaging : official journal of the American Society of Neuroimaging
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Although anterior circulation transient ischemic attacks (TIAs) tend to be more common in patients with extra- cranial carotid arterial disease than in those with intracranial carotid or middle cerebral arterial disease, the authors recently encountered 4 patients with both recurrent, stereotypical TIAs as well as isolated stenosis of their petrous internal carotid artery (ICA). While the gold standard for establishing the diagnosis of intracranial large-artery disease has always been conventional angiography, magnetic resonance angiography changes, confirmed with intra-arterial digital subtraction angiography in 2 of these patients, were quite sufficient to define the occlusive disease in each of the cases. Petrous ICA stenosis is not uncommon, but it has often been overshadowed by the search for extracranial ICA disease that might be amenable to surgical reconstruction.
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Brain atrophy may occur early in the course of multiple sclerosis (MS) and may be associated with disability. Brain magnetic resonance imaging (MRI) of 114 MS patients (group A) were analyzed for regional atrophy (vs age-/gender-matched controls) and T1 and T2 lesions using 4-point rating systems. Thirty-five separate patients (group B) were analyzed for cortical atrophy (ordinal scale), third ventricular width, and total T2 hyperintense lesion volume (computer assisted). ⋯ Mean kappa coefficients of ordinal ratings were 0.9 (intraobserver) and 0.8 (interobserver). Ordinal ratings correlated well with quantitative assessments. The authors conclude that brain atrophy is closely associated with physical disability and clinical course in MS patients and can be appreciated using a semiquantitative MRI regional rating system.
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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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Diffusion-weighted magnetic resonance imaging (DWI) detects acute ischemic infarcts with high lesion conspicuity. Determination of infarct age is difficult on DWI alone because infarct signal intensity (SIinfarct) on DWI is influenced by T2 properties ("T2 shine-through"). Maps of the apparent diffusion coefficient (ADC) reflect pure diffusion characteristics without T2 effects but have low lesion conspicuity. ⋯ All infarcts > 10 days old had an eDWI signal intensity lower than control tissue (hypointense appearance). The authors concluded that the use of eDWI, as a single set of images, reliably differentiates acute infarcts (< or = 5 days old) from infarcts > 10 days old. This feature would be expected to be helpful when the distinction between acute and nonacute infarction cannot be determined on clinical grounds.
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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.