2013 Cerebrovascular Diseases  
The intima-media thickness (IMT) as measured by ultrasonography of carotid arteries is an acknowledged non-invasive method for assessing the impact of vascular risk factors and the progression of cardiovascular disease risk over time. The average of the far wall IMT of the common carotid artery CCA (CIMT) from both right Fax +41 61 306 12 34 E-Mail karger@karger.ch www.karger.com Using a pulsed Doppler system with low transmitter frequency, conventional transcranial Doppler sonography (TCD)
more » ... ws blood flow velocities to be recorded from basal cerebral arteries through the intact skull. The Doppler signal obtained is assigned to a specific artery on the basis of indirect parameters: depth of the sample volume, position of the transducer, and direction of the blood flow. Since this method has no imaging component, the differentiation between individual vessels can be difficult. In addition, Abstracts Tutorials Cerebrovasc Dis 2013;35(suppl 2):1-77 Second-generation echo-contrast agents consist of synthetical microbubbles who respond with non-linear behavior to acoustic waves. Modern ultrasound scanners offer contrast-specific imaging modes and thus allow separation of signals arising from microbubbles and backscatter from tissue. In clinical and experimental neurosonology, echo-contrast agents are used not only for transcranial vascular imaging in patients with insufficient bone windows, but they can also be employed for semiquantitive analysis of cerebral perfusion and for analysis of extracranial plaque 18th Meeting of the ESNCH and 3rd Meeting of CARNet Cerebrovasc Dis 2013;35(suppl 2):1-77 Transcranial B-mode sonography (TCS) is a non-invasive, low-cost, short-duration neuroimaging method that allows highresolution imaging of deep brain structures in patients with movement disorders. With contemporary high-end ultrasound systems, image resolution of echogenic deep brain structures can even be higher on TCS than on MRI. On TCS, about 90% of patients with idiopathic Parkinson's disease (PD) exhibit abnormal hyperechogenicity of the substantia nigra (SN). The TCS finding of SN hyperechogenicity well discriminates PD from other Parkinsonian disorders such as multiple-system atrophy and welding-related Parkinsonism. In turn, normal SN echogenicity in combination with lenticular nucleus hyperechogenicity indicates an atypical Parkinsonian syndrome rather than PD with a specificity of more than 95%. TCS detects characteristic basal ganglia changes also in other movement disorders such as lenticular nucleus hyperechogenicity in idiopathic dystonia and Wilson's disease and caudate nucleus hyperechogenicity in Huntington's disease. Reduced echogenicity of midbrain raphe is frequent in depressive disorders and was found to correlate with responsivity to serotonin reuptake inhibitors. TCS reliably and safely displays deep brain stimulation electrodes in patients with movement disorders and allows postoperative monitoring of electrode location. Novel technologies Abstracts Lectures Cerebrovasc Dis 2013;35(suppl 2):1-77 5 allowing automated image analysis and image fusion with MRI and CT will further enhance the application of TCS in neurodegenerative brain disorders. Recently, we developed a new analysis tool, called multimodal -cal applications. Cerebral autoregulation is an important physiological mechanism that assists in maintaining cerebral blood flow relatively constant in the face of constantly changing blood pressure. The development of transcranial Doppler has allowed us to examine the response of cerebral flow velocity to beat by beat changes in blood pressure. This has resulted in significant advances in our understanding of autoregulation in the last thirty years. However, it remains unclear what role cerebral autoregulation may play clinically. This session will examine how autoregulation is affected in a number of pathological conditions including hypertension, 18th Meeting of the ESNCH and 3rd Meeting of CARNet
doi:10.1159/000351748 pmid:23712294 fatcat:kuw65edukrgkfdsnvwgsbj2r4m