Journal of neuroimaging : official journal of the American Society of Neuroimaging
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Hyperechoic middle cerebral artery: acute occlusion detected by transcranial duplex ultrasonography.
The authors describe the appearance of acute thromboembolic occlusion of the middle cerebral artery (MCA) using transcranial duplex ultrasonography. Acute occlusion of the MCA commonly leads to severe cerebral infarction. In patients with acute MCA occlusion, secondary edema and elevated intracranial pressure are major causes of increased morbidity and mortality. ⋯ Subsequent duplex ultrasonography and magnetic resonance angiography showed all four patients had ipsilateral occlusion of the internal carotid artery. Transcranial duplex ultrasonography assists in the early diagnosis of acute MCA occlusion. The affected vessel is displayed as a hyperechoic structure associated with no flow using Doppler examination.
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After diagnosing abnormality of cardiac and carotid-cerebral circulation in an infant with isolated ventricular septal defect (VSD) associated with severe congestive heart failure, the authors measured the carotid arterial blood flow volume (CABF). At 3 months, the patient was not thriving and had dyspnea because of severe congestive heart failure. The authors measured the VSD size/body surface area (BSA) ratio relative to the predicted value of the left ventricular end-diastolic dimension (%LVEDd), left-to-right shunt ratio (Qp/Qs), and the small stroke volume (SV)/BSA using echocardiography and cardiac catheterization. ⋯ The mean CABF, maxCABF, and minCABF were significantly lower than those of control children (VSD patient vs. controls; 2.7 +/- 0.4 vs. 4.5 +/- 0.6, 6.1 +/- 0.9 vs. 12.0 +/- 2.1, 1.2 +/- 0.2 vs. 1.7 +/- 0.4 mL/sec (mean +/- S. D.)), respectively (p < 0.01). The authors' results showed abnormal cardiac and carotid-cerebral circulation in an infant with large VSD associated with severe congestive heart failure.
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The authors present two comatose patients with brain swelling from anoxic encephalopathy. Nonenhanced computed tomography (CT) images showed increased density on the falx, on the tentorium, and in the basal cisterns, all of which falsely suggested subarachnoid hemorrhage. Autopsy in both patients failed to show subarachnoid hemorrhage. In rare circumstances, anoxic encephalopathy can mimic subarachnoid hemorrhage on nonenhanced CT.
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Comparative Study
Transcranial harmonic power duplex sonography for the evaluation of cerebral arteries.
Harmonic power-based duplex sonography is a new ultrasound method that improves the signal-to-noise ratio of extracranial vascular imaging. The authors evaluated this new method for transtemporal imaging of the basal cerebral arteries. Fundamental power-based duplex sonography (p-TCCS) and harmonic power-based duplex sonography (HI-p-TCCS) in combination with a novel perfluoropropane-containing ultrasound contrast agent (Optison) were investigated for the evaluation of the basal cerebral arteries in 12 healthy volunteers. ⋯ The spatial resolution was markedly increased with HI-p-TCCS, resulting in a striking difference in the detection of distal arterial segments and cortical and parenchymal branches. Except for the diastolic blood flow velocities (BFVs) in the M1 segment, the BFVs did not differ significantly between p-TCCS and HI-p-TCCS. Comparing HI-p-TCCS with 0.5 mL and 1.5 mL Optison, the authors found a small but significant reduction of the latency period (18.2 vs. 15.9 seconds, respectively; p < 0.01), a significant increase of the blooming phase (62.7 vs. 99.8 seconds, respectively; p < 0.0006) and a significant prolongation of the diagnostically useful signal enhancement (233.7 vs. 427.6 seconds, respectively; p < 0.004).
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Comparative Study
Acute optic neuritis: association with paranasal sinus inflammatory changes on magnetic resonance imaging.
The authors compared the frequency of paranasal sinus inflammatory changes (SIC) on brain magnetic resonance imaging (MRI) obtained from 23 patients with new onset acute optic neuritis (ON) and 48 control patients who underwent outpatient MRI of the brain for reasons other than ON. The authors found a higher frequency of paranasal SIC in patients with ON (83%) than in controls (54%) (p = 0.02). The distribution of paranasal SIC (in ON and in controls) was maxillary (83% and 52%), ethmoid (4% and 2%), frontal (9% and 14%), and sphenoid (4% and 10%). ⋯ Grade I SIC did not significantly differ between the groups. There was a trend (p = 0.09) toward a higher prevalence of bilateral sinus inflammatory changes in patients with bilateral ON. These findings suggest that ON may be associated with sinus inflammatory changes.