Cerebrovascular assessment of the high-risk patient: The role of transcranial doppler ultrasound

Doblar, Dennis D.

doi:10.1016/s1053-0770(96)80173-x

Cited by 14 publications

(5 citation statements)

References 89 publications

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“…Previous studies have suggested that the ACoA is a more important collateral pathway than collateral flow via the PCoA to maintain normal cerebral hemodynamics. 13,37,38 Computerized flow prediction models indicated that the ACoA is the major conduit of collateral blood supply, whereas the PCoA is presumed to be more important as source of collateral flow in patients with a small ACoA. 39 -41 Compared with control subjects, we found a significantly increased prevalence (65%) of collateral flow via the A1 segment, which is in accord with the prevalences described in the literature that varied between 46% and 80%.…”

Section: Discussionsupporting

confidence: 85%

Collateral Ability of the Circle of Willis in Patients With Unilateral Internal Carotid Artery Occlusion

Hendrikse

Hartkamp

Hillen

et al. 2001

Stroke

134

108

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Background and Purpose-The circle of Willis is regarded as the major source of collateral flow in patients with severe carotid artery disease. The purpose of the present study was to assess whether the presence of border zone infarcts is related to the collateral ability of the circle of Willis in symptomatic (transient ischemic attack, minor stroke) and asymptomatic patients with unilateral occlusion of the internal carotid artery (ICA). Methods-Fifty-one patients (35 symptomatic, 16 asymptomatic) and 53 control subjects were investigated. Patients had unilateral occlusion of the ICA and contralateral ICA stenosis between 0% and 69%.

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Section: Discussionsupporting

confidence: 85%

Collateral Ability of the Circle of Willis in Patients With Unilateral Internal Carotid Artery Occlusion

Hendrikse

Hartkamp

Hillen

et al. 2001

Stroke

134

108

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“…Based on anatomical[ 12 13 14 ] and radiological studies,[ 7 15 16 ] it has been shown that more than half of healthy subjects have anatomical variations in the CW. Recent studies have investigated the role of the CW in the development of collateral flow in ICA obstruction; these studies were based on mathematical models[ 17 18 19 ] and used transcranial Doppler ultrasound,[ 20 21 22 23 24 25 ] digital contrast–enhanced angiography,[ 3 26 ] or magnetic resonance angiography (MRA). [ 2 3 27 28 29 ] MRA has previously been shown to be well-suited to investigate the CW, in view of the fact that it is able to provide morphological as well as hemodynamic information concerning blood flow direction in individual vessels accurately.…”

Section: Introductionmentioning

confidence: 99%

Magnetic resonance angiographic evaluation of circle of Willis: A morphologic study in a tertiary hospital set up

Naveen¹,

Bhat²,

Karthik³

2015

Ann Indian Acad Neurol

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Background:Anatomy of circle of Willis (CW) shows wide variation in different individuals, population groups, and has vital clinical significance in causation and presentation of clinical disease. This study evaluates the anatomical variations, incidence of various common anomalies of CW in south Indian tertiary hospital set up, using three-dimensional time-of-flight (3D-TOF) magnetic resonance angiography (MRA).Materials and Methods:A total of 300 patients referred for neuroimaging study over a period of 2-year were included in the analysis. In this prospective and retrospective study, 198 men and 102 women; mean age, 55 years) underwent 3D-TOF MR angiograms of the CW using a 1.5-tesla MR scanner. Images were reviewed for anatomical configuration of the CW using maximum intensity projection (MIP) and 3D volume rendered images.Results:On analysis, a complete CW was seen in 50 (16.6%) of 300 subjects. An incomplete anterior and posterior CW was found in 66 (22%) The remaining 184 (61.3%) subjects had partially complete CW configuration. The most common type of CW in a single subject was anterior variant type A and posterior type variant E.Conclusion:We observed wide variation in CW configuration in our patients. The prevalence of complete configuration of the circle is 16.6%; slightly higher in females and younger subjects. Complete anterior circle was present in 77.3%. Most common anterior variant is type A (normal anterior configuration) with a prevalence of 66%. The most common posterior circle variant is type E (hypoplasia or absence of both PcomA) with 32.6%. Overall, CW variants are slightly more common among the women in comparison to men. Incidence of associated anomalies like aneurysm or arteriovenous malformation (AVM) was comparable to that described in literature.

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“…The collateral potential of the CW is believed to be dependent on the presence and size of its component vessels, [2][3][4] which vary among normal individuals. [5][6][7][8][9] Recent studies have investigated the role of the CW in the development of collateral flow in ICA obstruction; these studies were based on mathematical models 10 -12 and used transcranial Doppler ultrasound, [13][14][15][16][17][18] digital contrast-enhanced angiography, 2,19 or magnetic resonance angiography (MRA). 3,4,13,20 -22 The relative importance of the separate components of the CW have thus been assessed, although no clear consensus is found among these reports.…”

mentioning

confidence: 99%

Circle of Willis Collateral Flow Investigated by Magnetic Resonance Angiography

Hartkamp

Grond

Everdingen

et al. 1999

Stroke

172

149

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Background and Purpose-The circle of Willis (CW) is considered an important collateral pathway in maintaining adequate cerebral blood flow in patients with internal carotid artery (ICA) obstruction. We aimed to investigate the anatomic variation of the CW in patients with severe symptomatic carotid obstructive disease and to analyze diameter changes of its components in relation to varying grades of ICA obstruction and in relation to the presence or absence of (retrograde) collateral flow. Methods-Seventy-five patients with minor disabling neurological deficits and with ICA stenoses or occlusions were categorized into 4 groups according to the severity of ICA obstruction. This patient population reflected a relatively favorable subgroup of cerebral infarction (considering their minor neurological deficits). All subjects underwent magnetic resonance angiography, including magnetic resonance angiography sensitive to flow direction. CW morphology and the size of its components were determined and compared with those values in control subjects (nϭ100). Results-Compared

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Cerebrovascular assessment of the high-risk patient: The role of transcranial doppler ultrasound

Cited by 14 publications

References 89 publications

Collateral Ability of the Circle of Willis in Patients With Unilateral Internal Carotid Artery Occlusion

Collateral Ability of the Circle of Willis in Patients With Unilateral Internal Carotid Artery Occlusion

Magnetic resonance angiographic evaluation of circle of Willis: A morphologic study in a tertiary hospital set up

Circle of Willis Collateral Flow Investigated by Magnetic Resonance Angiography

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