Journal of neuroimaging : official journal of the American Society of Neuroimaging
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Case Reports
Unusual imaging findings in brain and spinal cord in two siblings with maple syrup urine disease.
Maple syrup urine disease (MSUD) is a rare metabolic disease affecting the neural tissue. While the brain abnormalities present on MRI are well known, spinal imaging features have not been studied. ⋯ To the best of our knowledge, spinal MRI findings in cases of MSUD have not been previously reported. Knowledge of spinal MRI findings may be useful in diagnosis of this rare disorder.
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The detection of microembolic signals in transcranial-Doppler monitoring is associated with a higher stroke risk. We investigated the correlation between the frequency of microembolic signals and the efficacy of the antiplatelet therapy in patients with a recent symptomatic carotid-artery stenosis. ⋯ Our study suggests that in patients with recent symptomatic carotid-artery stenosis the detection of more than one microembolic signals might serve as a useful marker for the effectiveness of the antiplatelet treatment.
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Posterior cerebral artery aneurysms are treatment challenge for the neurosurgeon. Parent artery occlusion, trapping and bypass have been the classic treatment options for aneurysms in this location. With the introduction of newer embolic agents such as Onyx®, endovascular intervention is now a viable therapy for these aneurysms. ⋯ This report illustrates the ability of a high-density liquid embolic agent to provide immediate reconstruction of a fusiform aneurysm in a distal location.
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Review
Application of chemical exchange saturation transfer (CEST) MRI for endogenous contrast at 7 Tesla.
Chemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI) indirectly images exchangeable solute protons resonating at frequencies different than bulk water. These solute protons are selectively saturated using low bandwidth RF irradiation and saturation is transferred to bulk water protons via chemical exchange, resulting in an attenuation of the measured water proton signal. CEST MRI is an advanced MRI technique with wide application potential due to the ability to examine complex molecular contributions. ⋯ Increased field strength translates to enhanced quantification of the metabolite of interest, allowing more fundamental studies on underlying pathophysiology. CEST contrast is affected by several tissue properties, such as the concentrations of exchange partners and their rate of proton exchange, whose effects have been examined and explored in this review. We have highlighted the background of CEST MRI, typical implementation strategy, and complications at 7 T.
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In transcranial sonography (TCS), hypoechogenic signal of mesencephalic raphe structures has been described as a frequent finding in unipolar depression. It remains unclear if raphe hypoechogenicity represents a correlate for an altered serotonergic system. The loudness dependence of auditory evoked potentials (LDAEP) has been proposed as an indirect indicator of central serotonergic activity. ⋯ There were no significant correlations with the psychometric assessments. At least in healthy subjects, our findings do not support the hypothesis that abnormal structural finding of hypoechogenic BR in TCS is accompanied by a functional impairment of serotonergic system as assessed by LDAEP. Further multimodal studies on patients with depressive disorders are needed to elucidate the impact of the hypoechogenic raphe signal in the pathophysiology of depression.