Journal of neuroimaging : official journal of the American Society of Neuroimaging
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Changes in partial pressure of carbon dioxide (PaCO2) are associated with a decrease in cerebral blood flow (CBF) during hypocapnia and an increase in CBF during hypercapnia. However, the effects of changes in PaCO2 on cerebral arterial compliance (Ca) are unknown. ⋯ Using a new mathematical model, we have described a reduction of Ca during hypocapnia. Further studies are needed to determine whether Ca may be an independent predictor of outcome in pathological conditions.
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Practice Guideline
American Society of Neurophysiologic Monitoring and American Society of Neuroimaging joint guidelines for transcranial doppler ultrasonic monitoring.
The American Society of Neurophysiologic Monitoring (ASNM) and American Society of Neuroimaging (ASN) Guidelines Committees formed a joint task force and developed guidelines to assist in the use of transcranial Doppler (TCD) monitoring in the surgical and intensive care settings. Specifically, these guidelines: (1) delineate the objectives of TCD monitoring; (2) characterize the responsibilities and behaviors of the sonographer during monitoring; (3) describe methodological and ethical issues uniquely relevant to monitoring. ⋯ We agree with the guidelines of other professional societies regarding the technical and professional qualifications of individuals responsible for TCD signal acquisition and interpretation (Class III evidence, Type C recommendation). On the basis of current clinical literature and scientific evidence, TCD monitoring is an established monitoring modality for the: (1) assessment of cerebral vasomotor reactivity and autoregulation; (2) documentation of the circle of Willis functional status; (3) identification of cerebral hypo- and hyperperfusion, recanalization and re-occlusion; and (4) detection of cerebral emboli (Class II and III evidence, Type B recommendation).
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White matter lesions (WMLs) are age-related manifestations of ischemic cerebrovascular disease and increase the risk for Alzheimer's disease (AD). The apolipoprotein E (ApoE) ɛ4 allele is a risk factor for late onset AD and has been related to low cerebrospinal fluid (CSF) Aβ42 levels and to cerebrovascular disease. The present study analyzed the relationship between WMLs, ApoE-ɛ4 genotype, and low CSF Aβ42. ⋯ A high WML load may interact with the ApoE-ɛ4 genotype and increase the risk for reduced CSF Aβ42 in patients attending a memory clinic.
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Case Reports
Parry-Romberg syndrome and Rasmussen encephalitis: possible association. Clinical and neuroimaging features.
Parry-Romberg syndrome (PRS) is a sporadic disease of unknown etiology with typical onset in childhood or in young adults. It is characterized by a slow and progressive atrophy affecting one side of the face, the skin, the subcutaneous tissue, the muscles, the cartilages, and the underlying bony structures. The neurological symptoms usually include focal epilepsy, migraine, and unilateral brain lesions on the same side as the atrophy. ⋯ We report the clinical and neuroradiological findings in a 6-year-old boy, presenting with focal hemifacial and arm motor seizures and progressive facial hemiatrophy. Serial MR imaging studies revealed progressive brain hemispheric signal alterations and atrophy. This would thus suggest acoexistence of PRS and RE.
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Three-dimensional (3D) ultrasound imaging is a new technique that maximizes the information and image quality of traditional 2-dimensional (2D) B-mode scanning. The aim of this study was to evaluate the ability of the 3D ultrasound technique to characterize ulcerated atherosclerotic carotid plaque. ⋯ 3D ultrasound reliably characterized the surface morphology of atherosclerotic carotid plaques. A trend of superiority of 3D ultrasound over 2D was found in detecting ulcers of carotid artery plaque.