Journal of neuroimaging : official journal of the American Society of Neuroimaging
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Usually, microembolic signal (MES) monitoring is performed for MESs arising from downstream sources. The aim of this study is to describe the special characteristics of MESs originating from nearby sources in the middle cerebral artery (MCA). ⋯ MESs recorded from MCA stenoses may have special characteristics of multiple frequencies on both post-FFT spectra and pre-FFT time domain signals. Our findings may represent rotating or vibrating emboli as they are just dislodged from the thrombus and are moving from the vessel wall to the center. Further clinical and laboratory studies are needed to confirm this hypothesis.
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Involvement of the brain is one of the most important complications of Behçet's disease, but its diagnosis is difficult because of the lack of effective imaging tools. Therefore, technetium-99m ethyl cysteinate dimer (Tc-99m ECD) single-photon emission computed tomography (SPECT) of the brain was used to detect abnormal regional cerebral blood flow in patients with neuro-Behçet's syndrome (NBS). ⋯ The parietal lobes were the most common areas with hypoperfusion lesions. Tc-99m ECD brain SPECT is a more sensitive and useful tool than brain MRI for detecting hypoperfusion areas of the brain in NBS patients.
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Cerebral malaria occurs in 2% of patients infected by Plasmodium falciparum. Magnetic resonance imaging findings of small white matter infarcts due to cerebral malaria have been previously reported, however nonspecific. Since diffusion-weighted imaging can differentiate acute embolic infarcts from other chronic or nonspecific white matter lesions, it may aid diagnosis of this illness in patients who travel to endemic areas.
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Double Inversion Recovery Magnetic Resonance Imaging (DIR) consists of two adiabatic non-selective inversion pulses applied before a Turbo Spin Echo (TSE) sequence, in order to suppress the signal from two tissues with different longitudinal relaxation times T(1) simultaneously. In the brain, DIR is used to selectively image the gray matter (GM) by nulling the signal from white matter (WM) and cerebrospinal fluid (CSF). The main limitation of the technique remains the intrinsic low SNR due to the specific preparation of the longitudinal magnetization. The recent availability of high field magnets operating at 7 T for human imaging offers the advantage of higher SNR. This study shows the feasibility of brain Double Inversion Recovery Magnetic Resonance Imaging (DIR-MRI) at 7 T in vivo in healthy volunteers. ⋯ DIR is feasible at 7 T despite the problems associated with B(1) in-homogeneity.
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A persistent trigeminal artery (PTA) has been found in a number of cerebrovascular diseases. A 73-year-old asymptomatic woman was noted to have a left PTA and left subclavian steal by catheter angiography. Carotid duplex revealed a peak systolic flow velocity of 294 cm/s in the internal carotid artery (ICA) and an ICA to common carotid artery ratio > 4, suggestive of a high-grade stenosis. ⋯ Transcranial Doppler found an alternating flow pattern in the basilar artery (mean flow velocity [MFV] = 18 cm/s) and left vertebral artery (MFV = 43 cm/s). During brachial hyperemia, the MFV increased by 178% in the basilar artery and 102% in the left vertebral artery. The data suggest that a PTA may compensate for subclavian steal and may have a protective hemodynamic role in this setting.