Sensitivity and specificity of color duplex ultrasound measurement in the estimation of internal carotid artery stenosis: A systematic review and meta-analysis

Division of Vascular Surgery, McMaster University, Toronto, Ontario, Canada.
Journal of Vascular Surgery (Impact Factor: 3.02). 07/2005; 41(6):962-72. DOI: 10.1016/j.jvs.2005.02.044
Source: PubMed


Duplex ultrasound is widely used for the diagnosis of internal carotid artery stenosis. Standard duplex ultrasound criteria for the grading of internal carotid artery stenosis do not exist; thus, we conducted a systematic review and meta-analysis of the relation between the degree of internal carotid artery stenosis by duplex ultrasound criteria and degree of stenosis by angiography.
Data were gathered from Medline from January 1966 to January 2003, the Cochrane Central Register of Controlled Trials and Database of Systematic Reviews, Database of Abstracts of Reviews of Effects, ACP Journal Club, UpToDate, reference lists, and authors' files. Inclusion criteria were the comparison of color duplex ultrasound results with angiography by the North American Symptomatic Carotid Endarterectomy Trial method; peer-reviewed publications, and >/=10 adults.
Variables extracted included internal carotid artery peak systolic velocity, internal carotid artery end diastolic velocity, internal carotid artery/common carotid artery peak systolic velocity ratio, sensitivity and specificity of duplex ultrasound scanning for internal carotid artery stenosis by angiography. The Standards for Reporting of Diagnostic Accuracy (STARD) criteria were used to assess study quality. Sensitivity and specificity for duplex ultrasound criteria were combined as weighted means by using a random effects model. The threshold of peak systolic velocity >/=130 cm/s is associated with sensitivity of 98% (95% confidence intervals [CI], 97% to 100%) and specificity of 88% (95% CI, 76% to 100%) in the identification of angiographic stenosis of >/=50%. For the diagnosis of angiographic stenosis of >/=70%, a peak systolic velocity >/=200 cm/s has a sensitivity of 90% (95% CI, 84% to 94%) and a specificity of 94% (95% CI, 88% to 97%). For each duplex ultrasound threshold, measurement properties vary widely between laboratories, and the magnitude of the variation is clinically important. The heterogeneity observed in the measurement properties of duplex ultrasound may be caused by differences in patients, study design, equipment, techniques or training.
Clinicians need to be aware of the limitations of duplex ultrasound scanning when making management decisions.

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Available from: Catherine M Clase, Mar 21, 2014
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    • "Colour-coded duplex ultrasound would be a relatively inexpensive alternative without radiation burden. For carotid artery stenosis high sensitivity and specificity values have been reported [13]. Although the carotid bifurcation can be well visualized, ultrasound does not allow visualization of the complete branching of the external carotid artery, especially in the postoperative, irradiated neck, it is highly operator dependent and allows only segmental views of vascular anatomy rather than longitudinal images. "
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    ABSTRACT: Introduction: The aim of the study was to compare the detectability of neck vessels with contrast enhanced magnetic resonance angiography (MRA) in the setting of a whole-body MRA and multislice computed tomography angiography (CTA) for preoperative vascular mapping of head and neck. Methods: In 20 patients MRA was performed prior to microvascular reconstruction of the mandible with osteomyocutaneous flaps. CTA of the neck served as the method of reference.1.5 T contrast enhanced magnetic resonance angiograms were acquired to visualize the vascular structures of the neck in the setting of a whole-body MRA examination. 64-slice spiral computed tomography was performed with a dual-phase protocol, using the arterial phase images for 3D CTA reconstruction. Maximum intensity projection was employed to visualize MRA and CTA data. To retrieve differences in the detectability of vessel branches between MRA and CTA, a McNemar test was performed. Results: All angiograms were of diagnostic quality. There were no statistically significant differences between MRA and CTA for the detection of branches of the external carotid artery that are relevant host vessels for microsurgery (p = 0.118). CTA was superior to MRA if all the external carotid artery branches were included (p < 0.001). Conclusions: MRA is a reliable alternative to CTA in vascular mapping of the cervical vasculature for planning of microvascular reconstruction of the mandible. In the setting of whole-body MRA it could serve as a radiation free one-stop-shop tool for preoperative assessment of the arterial system, potentially covering both, the donor and host site in one single examination.
    Head & Face Medicine 05/2014; 10(1):16. DOI:10.1186/1746-160X-10-16 · 0.85 Impact Factor
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    • "All duplex ultrasound scanning was performed by a registered vascular scientist using a standard protocol to assess the common, internal, and external carotid arteries bilaterally. In addition to visual estimates of stenosis, Doppler flow velocities were used to estimate stenoses as follows: ≥130 cm/s, >50%; >180 cm/s, >65%; >230 cm/s, >70%; >300 cm/s, >80% [22]. "
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    ABSTRACT: Restenosis of the carotid artery is common following carotid endarterectomy, but analysis of lesion composition has mostly been based on histological study of explanted restenotic lesions. This study investigated the ability of 3T cardiovascular magnetic resonance (CMR) to determine the components of recurrent carotid artery disease and examined whether these differed from primary atherosclerotic plaque. 50 patients underwent 3T CMR of both carotid arteries using a standard multicontrast protocol: time-of-flight (TOF), T1-weighted (T1W), T2-weighted (T2W), and PD-weighted (PDW) Turbo-Spin-Echo (TSE) sequences. 25 patients had previously undergone carotid endarterectomy (mean time since surgery 1580 days, range 45-6560 days), and 25 with primary asymptomatic atherosclerotic plaques served as controls. Two experienced reviewers analysed the multicontrast CMR images according to the presence or absence of major plaque features and assigned an overall classification type. In patients with recurrent carotid disease following endarterectomy, the mean degree of restenosis was 51% (range 30-90%). Three distinct types of restenosis were identified: 5 patients (20%) showed CMR characteristics of fibro-atheromatous tissue, 11 patients (44%) had plaque features consistent with possible myointimal (fibromuscular) hyperplasia, and 6 patients (24%) had recurrent plaque suggestive of further lipid accumulation. Three patients (12%) showed evidence of post-surgical dissection of the carotid intima. Compared to primary atherosclerotic plaques, restenotic plaques were more likely to contain fibro-atheromatous tissue (p = 0.05) and smooth muscle (p < 0.01), and less likely to contain lipid (p < 0.01). Composition did not differ significantly between patients with early and late restenosis. As defined by CMR, restenotic lesions of the carotid artery fall into three distinct types and differ in composition from primary atherosclerotic plaques. If validated by subsequent histological studies, these findings could suggest a role for CMR in detecting high-risk (i.e. lipid-rich) restenotic lesions.
    Journal of Cardiovascular Magnetic Resonance 01/2014; 16(1):5. DOI:10.1186/1532-429X-16-5 · 4.56 Impact Factor
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    ABSTRACT: The search for embolic sources has high priority in patients presenting with suspected cerebral embolism. Non-invasive cardiovascular ultrasound is frequently used to reveal the presence of carotid stenosis and cardiac disorders with embolic potential. Transesophageal echocardiography (TEE) provides images of aortic atherosclerosis, shown to be associated with increased risk of stroke. Some guidelines claim that TEE should be reserved for younger patients. In recent years microembolic signal (MES) detection with transcranial Doppler has emerged as a tool with potential of identifying patients at high risk of recurrent embolism. We compared the diagnostic value of transthoracic and transesophageal echocardiography in relation to age in stroke/TIA patients. We found that among 453 patients investigated with TEE during 3 years, TEE had a higher proportion of relevant findings, e.g. complex aortic arch atheromas, in patients aged > 50 years compared to those < 50 years. Carotid stenosis is a well known cause of embolism; however the association between routinely described plaque morphology and risk of recurrent embolism is not clear. In 197 patients with symptomatic high grade carotid stenosis, we found a strong correlation between the side of symptomatic stenosis and occurrence of microembolic signals on transcranial Doppler compared to the contralateral hemisphere. The occurrence of MES, however, only tended to correlate to plaque morphology. Complex aortic atheromas are often found in the distal aortic arch or proximal descending aorta. Therefore, we investigated if regional flow conditions, with retrograde diastolic flow, make plaques located in the aorta distal to the cerebral branches relevant as sources of cerebral embolism; we found that this possibility does exist. Previous research has shown hyperlipidemic rabbits to be a useful atherosclerosis model. The possibility to perform serial non-invasive evaluation of the aorta in the same animal would add a new dimension in the study of pathophysiology and treatment effects. Therefore, we validated high frequency transthoracic ultrasound for repeated in vivo measurements of aortic intima-media thickness in hyperlipidemic rabbits. To conclude, our study shows that TEE has the highest yield of relevant information in stroke/TIA patients above 50 years of age. In carotid stenosis, plaque morphology as described by Gray-Weale scaling shows only a tendency to correlate with microembolism. Local flow conditions can allow plaques located in the aorta distal to the cerebral arteries to embolize to the brain. To facilitate future studies of aortic atherosclerosis, we developed and validated an animal model for repeated ultrasound investigations of aortic intima media thickness.
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