This study aimed to compare the results of TCD and DSA assessments of the LMCs and to establish a reference for TCD in severe occlusive ICA and MCA disorders. To determine the accuracy of TCD in LMC flow assessment in patients with severe occlusive ICA and MCA disorders, we compared DSA and TCD findings in patients with these arterial disorders. Several TCD studies have been published regarding the LMCs ( 8- 14) however, no study has identified a standard for LMCs. Moreover, dynamic observations of the LMCs become increasingly important for clinicians when making decisions regarding interventional therapy. TCD is a noninvasive technique and comprises a promising alternative to DSA for collateral supply evaluation ( 6, 7). Modern diagnostic imaging techniques, such as Xenon enhanced computed tomography (CT), single photon emission CT, positron emission tomography (PET), CT perfusion, magnetic resonance (MR) perfusion, cerebral angiography (digital subtraction angiography, DSA), and transcranial doppler (TCD), have improved the assessment of cerebral blood flow via collaterals. The presence of LMCs has also been associated with better outcomes, a reduced infarct size, and faster recanalization ( 5). In chronic hypoperfusion that results from severe carotid or MCA stenosis or occlusion, the LMCs have a high frequency ( 4) and maintain cerebral blood flow when the primary collateral flow is insufficient. As the foremost part of the secondary collaterals, the leptomeningeal collaterals (LMCs), which are also referred to as leptomeningeal anastomoses (LMAs) or pial collaterals, are small arterial connections that join the terminal cortical branches of the major (middle, anterior, and posterior) cerebral arteries along the brain surface. The primary collaterals include the arterial segments of the circle of Wills, which exhibit considerable variability and frequent asymmetry, with an ideal configuration present in only a minority of cases. This failure plays a pivotal role in the pathophysiology of cerebral ischemia, especially ischemia caused by severe occlusion of the internal carotid artery (ICA) or middle cerebral artery (MCA), which has a poor course ( 1) and high recurrence of stroke ( 2, 3). The cerebral collateral circulation refers to the subsidiary network of vascular channels that stabilize cerebral blood flow when principal conduits fail. Transcranial Doppler Ultrasonography Collateral Circulation Internal Carotid Artery Stenosis Middle Cerebral Artery Occlusion 1.
TCD is a reliable tool for LMC assessment in patients with severe occlusive ICA and MCA disorders.
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