الفهرس 
ANATOMY…Only 14 pages are availabe for public view
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Abstract
The introduction of transcranial Doppler sonography (TCD) by Aaslid in 1982 gave new force to neurosonology, as it provides a mobile, non-¬invasive, and cost- effective method to study intracranial haemodynamics at the patient’s bedside. Transcranial color-coded - duplex sonography (TCCS) is relatively a new technical development. It combines non-invasive imaging of intracranial vessels and parenchymal structures at a high spatial resolution. TCCS is increasingly accepted as a valuable method in neurovascular diagnostics. TCCS is becoming a reliable tool for detecting the occlusion and narrowing of major intracranial arterial trunks. TCCS can image the collateral flow through the anterior and posterior communicating arteries in patients with unilateral high-grade stenosis or occlusion of the extracranial internal carotid artery without using potentially dangerous compression tests. The rapid sonographic assessment of cerebral haemodynamics in a neurosurgical patient with increased intracranial pressure can guide further management. The use of sonographic contrast agents can increase the number of conclusive TCCS studies in patients with insufficient acoustic windows. Middle cerebral artery flow velocity detected by means of TCCS can help identify MCA stem occlusion as well as MCA branch occlusion. TCCS allows a distinction between intracerebral hemorrhage and ischemic stroke in the majority of patients and provides insights into the dynamic evolution of cerebrovascular diseases and resulting complications. Although the accuracy of TCCS is at present inferior to that of CT. technical improvements in the future will make TCCS more reliable and suitable for the differentiation of stroke subtypes. The main limitation of TCCS, like that of conventional TCD is the need for an adequate acoustic window. The inability to image intracranial vessels can be overcome with echo-contrast agents. Transcranial Doppler ultrasound is noninvasive imaging modality as it is suitable bed-sided examination for high risk bed ridden patients in ICU and for patients in the post operative care unit. It also gives indispensable information about the condition of intracranial arteries and has no contraindications for its use. In the hands of an experienced examiner, A combination of carotid duplex and TCCS provides a non-invasive method for more accurate haemodynamic study of cerebral circulation.