Assessment of ≥50% and <50% Intracranial Stenoses by Transcranial Color-Coded Duplex Sonography

Abstract

Background and Purpose-A favorable risk-benefit ratio for warfarin compared with aspirin has been reported for the prevention of major vascular events in symptomatic Ն50% intracranial stenoses. Transcranial color-coded duplex sonography (TCCS) criteria providing an accurate detection of Ն50% and Ͻ50% stenoses of the anterior, middle, and posterior cerebral arteries and basilar and vertebral arteries were evaluated retrospectively with angiography used as the standard of reference. Methods-Prospectively collected TCCS, extracranial color-coded duplex sonography, and intra-arterial digital subtraction angiography data of 310 patients were reviewed. The patients had angiography for confirmation of symptomatic extracranial Ն70% carotid stenoses, symptomatic stenoses (peak systolic velocity higher than the corresponding mean value ϩ2 SDs of 104 normal subjects), and occlusions of the middle cerebral or basilar artery previously assessed by ultrasound. The sonographer was not aware of angiographic findings. Results-TCCS would have detected all 31 of Ն50% intracranial stenoses with 1 false-positive and 35 of 38 Ͻ50% stenoses with 3 false-positives. One of 69 stenoses (1%) and 280 of 2741 normal arteries (10%) were missed because of inadequate insonation windows. The corresponding peak systolic velocity cutoffs for Ն50%/Ͻ50% stenoses were Ն155/Ն120 cm/s (anterior cerebral artery), Ն220/Ն155 cm/s (middle cerebral artery), Ն145/Ն100 cm/s (posterior cerebral artery), Ն140/Ն100 cm/s (basilar artery), and Ն120/Ն90 cm/s (vertebral artery). Conclusions-TCCS may reliably assess Ն50% and Ͻ50% basal cerebral artery narrowing and prove useful for noninvasive management of patients with symptomatic intracranial stenoses. (Stroke. 1999;30:87-92.)

Transcranial Color-Coded Duplex Sonography for Detection of Distal Internal Carotid Artery Stenosis

“…28 With sonography, stenoses of the MCA, ACA, PCA, and BA were assessed as previously described. 29 The sonography investigation was blinded to the results of the DSA but not to those of prior MRA studies, which led to further diagnostic work-ups.…”

Transcranial Doppler findings in middle cerebral arterial occlusive disease in relation to degree of stenosis and presence of concomitant stenoses

“…[19][20][21] Although the clinical value of transcranial color Doppler sonography (TCCD) in the assessment of intracranial vessel abnormalities is still under evaluation, TCCD allows visualization of the vessels of interest and is reported to be superior to TCD. 19 TCCD has been reported to be a valuable method to detect stenoses of less than 50% in large intracranial vessels, with a high accuracy, 22 and to assess the collateral function of smaller communicating vessels. 23,24 Furthermore, TCCD enables the sonographer to correct the angle of insonation, which could be larger than expected in elderly patients with tortuous vessels, in patients with intracranial stenosis, and when a mass effect is present.…”

Neurosonological Evaluation of the Acute Stroke Patients

“…The diagnostic criteria for intracranial stenosis with their velocity threshold are different between TCD and TCCS, because of the angle-corrected measurements with TCCS. Angle corrected threshold have an higher sensitivity to detect arterial narrowing because of stenosis or vasospasm (Baumgartner et al 1999), and they do not cause a decreased intrarater or interrater reproducibility, as compared to non-corrected measurements (Baumgartner et al 1994;Maeda et al 1990;Stolz et al 2001). These considerations lead to the Consensus Statement 4 and 5 about angle-corrected measurements (Fig.…”

“…Some relevant aspects of intracranial large artery disease, as recently stated and summarized (Gorelick et al 2008), are: -the magnitude of the public health problem; -the risk of stroke and other cardiovascular diseases associated with intracranial occlusive disease; -the etiology; -medication and non-medication approaches to treatment and prevention; -gaps in our understanding of intracranial occlusive disease and possible next steps to unravel enigmas related to this disorder. The evaluation of the intracranial atherosclerosis and stenosis has addressed in the literature mainly in the setting of the post-acute phase and the diagnostic criteria for all techniques are not directly applicable in the acute phase; for example the TCCS criteria (Baumgartner et al 1999) were selected and validated in a stable situation, because of the frequent presence of a transient intracranial stenosis (TIBI grade 4 and COGIF grade 4b) during the recanalization process of an occluded intracranial artery; therefore it is not possible to define criteria for a dynamically changing situation and the persistence of the stenosis days and weeks after the acute phase may more reliably indicate the intracranial atherosclerosis as the cause of the cerebrovascular event (Nedelmann et al 2009;Malferrari et al 2007;Malferrari et al 2008). Because of these considerations, the diagnosis of intracranial stenosis is not a main item in the ultrasound monitoring of the acute phase of ischemic stroke.…”