Duplex ultrasound and magnetic resonance angiography compared with digital subtraction angiography in carotid artery stenosis: a systematic review

Restenosis Is More Frequent After Carotid Stenting Than After Endarterectomy

Background and Purpose—

Carotid angioplasty and stenting (CAS) may be more often associated with residual or recurrent stenosis than carotid endarterectomy (CEA). We compared the rates of restenosis in patients treated with CAS or CEA in the EVA-3S trial.

Methods—

Five hundred seven patients (242 treated by CAS and 265 by CEA) had carotid ultrasound follow-up (mean carotid ultrasound follow-up, 2.1 years) according to a predefined protocol. Carotid restenosis of 50% to 69% was diagnosed on planimetry, whereas carotid restenosis of ≥70% or occlusion was diagnosed using either planimetry or velocity criteria.

Results—

The rate of carotid restenosis of ≥50% or occlusion was significantly higher after CAS (12.5%) than after CEA (5.0%; time ratio, 0.16; 95% CI, 0.03–0.76; P =0.02). The rates of severe restenosis of ≥70% or occlusion were low and did not differ significantly between the 2 groups (3-year rates are 3.3% in the CAS group and 2.8% in the CEA group). Age at baseline was the only vascular risk factor significantly associated with carotid restenosis. Our study could not detect any effect of carotid restenosis on ipsilateral stroke.

Conclusions—

The short-term rate of carotid restenosis of ≥50% or occlusion is ≈2.5-times more common after CAS than after CEA, a difference accounted for by an excess risk in moderate restenosis. More data with longer follow-up are needed to assess the rates of late severe restenosis and to determine the relation between restenosis and recurrent stroke over time.

[Ocular ischemic syndrome]

Ocular ischemic syndrome (OIS) is a group of ocular diseases caused by chronic artery occlusion usually involving the internal carotid artery. Patients suffer from visual loss and pain. OIS is a rare disease which can be confounded with diabetic retinopathy or an older central retinal vein occlusion. The only therapy is to treat the neovascular complications. Due to the high mortality of OIS patients, medical and neurological examinations are mandatory. We discuss the clinical findings and diagnostic and therapeutic options of OIS patients in this paper.

Risk factors for ischemic stroke and transient ischemic attack in patients under age 50

To analyze risk factors for ischemic stroke and transient ischemic attack (TIA) in young adults under the age of 50. To make recommendations for additional research and practical consequences. From 97 patients with ischemic stroke or TIA under the age of 50, classical cardiovascular risk factors, coagulation disorders, history of migraine, use of oral contraceptives, cardiac abnormalities on ECG and echocardiography, and the results of duplex ultrasound were retrospectively analyzed. Literature was reviewed and compared to the results. 56.4% of the patients had hypertension, 12.1% increased total cholesterol, 20% hypertriglyceridemia, 31.5% an increased LDL-level, 32.6% a decreased HDL-level and 7.2% a disturbed glucose tolerance. Thrombophilia investigation was abnormal in 21 patients and auto-immune serology was abnormal in 15 patients. Ten of these patients were already known with a systemic disease associated with an increased risk for ischemic stroke (i.e. systemic lupus erythematosus). The ECG was abnormal in 16.7% of the cases, the echocardiography in 12.1% and duplex ultrasound of the carotid arteries was in 31.8% of the cases abnormal. Conventional cardiovascular risk factors are not only important in patients over the age of 50 with ischemic stroke or TIA, but also in this younger population under the age of 50. Thrombophilia investigation and/ or autoimmune serology should be restricted to patients without conventional cardiovascular risk factors and a history or other clinical symptoms associated with hypercoagulability and/ or autoimmune diseases.

Discordant findings in color-coded duplex-sonography and magnetic resonance angiography in symptomatic internal carotid artery stenosis: implications for diagnostic work-up and early intervention

BACKGROUND

Magnetic resonance angiography (MRA) is supposed to be the new 'gold standard' in the diagnosis of atherosclerotic disease of the extracranial arteries.

METHODS

A case report is presented on a patient in whom discordant findings of the status of the left internal carotid artery (ICA) were identified in color-coded duplex-sonography and MRA.

RESULTS

Left ICA stenosis was suspected in duplex-sonography, yet not confirmed in contrast-enhanced (CE) MRA reconstruction. Diagnosis was confirmed after surgery and in subsequent analysis of the original CE-MRI data.

CONCLUSIONS

The analysis of source images must not be missed in MRA examinations. Conventional duplex-sonography may be superior in the estimation of the embolic potential of vascular lesions. Advanced CE techniques may therefore be adequate tools in differentiating patients eligible for carotid endarterectomy (CEA) or carotid stenting, avoiding the risk of peri-interventional iatrogenic complications. It should urgently be further improved and validated.

Characterization of carotid artery plaques with USPIO-enhanced MRI: assessment of inflammation and vascularity as in vivo imaging biomarkers for plaque vulnerability

To evaluate ultra small superparamagnetic iron oxide particles (USPIO) enhanced magnetic resonance (MR) imaging for characterization of atherosclerotic carotid plaques by assessing vascularity and plaque inflammation, besides contrast-enhanced MR angiography (CE-MRA) of the carotid artery stenosis. Twelve patients with severe carotid artery stenosis, scheduled for endarterectomy, underwent MRI of the carotid artery bifurcation using SHU 555 C at a dose of 40 μmol Fe/kg BW. The MR imaging protocol comprised pre- and post-contrast T2*-w, a first-pass CE-MRA and dynamic T1-w sequences. For quantitative data analysis, the signal intensities (SI) were measured and SNR-data (SNR = SI(blood/plaque/bone marrow)/standard deviation(noise)) as well as ΔSI-data (SNR(post)-SNR(pre)) were calculated. In addition, two radiologists rated the diagnostic performance of first-pass MRA according to a four level decision scale. Staining of anti-dextran (SHU 555 C) and anti-CD68 (macrophages) was performed for immunohistological confirmation. Plaque sections with a T2*-w signal decline (intracellular USPIO accumulation in macrophages) showed significantly changes (mean -14%, 95% CI, -5 to -20%; P < 0.01) and corresponding plaque regions had significantly higher (15.15 ± 1.76 vs. 5.22 ± 1.50; P < 0.01) T1-w enhancement data (global estimation of vascularity). The first-pass MRA of the supra-aortal vessels provided images of diagnostic quality. Representative immunohistology sections revealed colocalization of dextran- and CD68-immunoreactive cells. USPIO-enhanced MRI is feasible for in vivo assessment of vascularity and macrophage content in atherosclerotic carotid plaques, determining an association of these potential imaging biomarkers of plaque vulnerability. Diagnostic MRA of the supra-aortal vessels can be imaged additionally with a single administration of SHU 555 C.

The role of CT and MRI in the emergency evaluation of persons with suspected stroke

As a growing number of therapeutic treatment options for acute stroke are being introduced, multimodal acute neuroimaging is assuming a growing role in the initial evaluation and management of patients. Multimodal neuroimaging, using either a CT or MRI approach, can identify the type, location, and severity of the lesion (ischemia or hemorrhage); the status of the cerebral vasculature; the status of cerebral perfusion; and the existence and extent of the ischemic penumbra. Both acute and long-term treatment decisions for stroke patients can then be optimally guided by this information.

Magnetic resonance imaging in neonatal stroke

Neonatal stroke occurs in 1 in 2300-5000 live births, the incidence of which is lower than that in adults, but still higher than that in childhood. The higher incidence of perinatal stroke in preterm and term infants compared to stroke in childhood may be partly explained by higher detection rates using routine fetal ultrasound and postnatal cranial sonography. In addition, there is greater availability of magnetic resonance imaging (MRI) for neuroimaging in preterm and full-term infants, which is due in part to the availability of MR-compatible incubators and MR systems at or near the neonatal intensive care unit. In addition, the wide range of MR techniques, such as T2-, diffusion- and susceptibility-weighted imaging allows improved visualization and quantification of neonatal stroke or hypoxic-ischemic injury. This chapter reviews the MR neuroimaging modalities that actually assist the clinician in the detection of neonatal stroke.

Comparison of dual-source CT angiography and MR angiography in preoperative evaluation of intra- and extracranial vessels: a pilot study

Besides the assessment of carotid artery stenosis, evaluation of the vascular anatomy and lesions within both the extra- and intracranial arteries is crucial for proper clinical evaluation, treatment choice and planning. The purpose of our study was to evaluate the potential of dual-source CTA and 3T-MRA. In 16 symptomatic CAS patients, contrast-enhanced DSCT and 3T-MRA examinations were performed. For DSCT a dual-energy protocol with a 64 x 0.6-mm collimation was applied. In 3T-MRA intracranial high-resolution unenhanced TOF and extracranial contrast-enhanced MRA were performed. All examinations were analyzed for relevant morphologic and pathologic features or anomalies, and a total of 624 vessel segments were scored. All examinations were of diagnostic image quality with good to excellent vessel visibility. Almost all intracranial arteries were significantly better visualized by MRA compared to CTA (five of six vessels, p < 0.05). DSCT however allowed for further morphological carotid stenosis description, especially with respect to calcification. Although MRA proved to be superior in visualization of smaller intracranial arteries, all pre-interventionally relevant information could be perceived from DSCT. DSCT and MRA may both be regarded as a reliable, fast, pre-interventional imaging investigation in patients with carotid artery stenosis.

Optimal cut-off criteria for duplex ultrasound for the diagnosis of restenosis in stented carotid arteries: review and protocol for a diagnostic study

BACKGROUND

Carotid angioplasty with stenting is a relatively new, increasingly used, less-invasive treatment for the treatment of symptomatic carotid artery stenosis. It is being evaluated in ongoing and nearly finished randomized trials. An important factor in the evaluation of stents is the occurrence of in-stent restenosis. An un-stented carotid artery is likely to have a more elastic vessel wall than a stented one, even if stenosis is present. Therefore, duplex ultrasound cut-off criteria for the degrees of an in-stent stenosis, based on blood velocity parameters, are probably different from the established cut-offs used for un-stented arteries. Routine criteria can not be applied to stented arteries but new criteria need to be established for this particular purpose.

METHODS/DESIGN

Current literature was systematically reviewed. From the selected studies, the following data were extracted: publication year, population size, whether the study was prospective, duplex ultrasound cut-off criteria reported, which reference test was used, and if there was an indication for selection bias and for verification bias in particular. Previous studies often were retrospective, or the reference test (DSA or CTA) was carried out only when a patient was suspected of having restenosis at DUS, which may result in verification bias. :

RESULTS

In general, the velocity cut-off values for stenosis measurements in stented arteries were higher than those reported for unstented arteries. Previous studies often were retrospective, or the reference test (DSA or CTA) was carried out only when a patient was suspected of having restenosis at DUS, which may result in verification bias.

DISCUSSION

To address the deficiencies of the existing studies, we propose a prospective cohort study nested within the International Carotid Stenting Study (ICSS), an international multi-centre trial in which over 1,700 patients have been randomised between stenting and CEA. In this cohort we will enrol a minimum of 300 patients treated with a stent. All patients undergo regular DUS examination at the yearly follow-up visit according to the ICSS protocol. To avoid verification bias, an additional computed tomography angiography (CTA) will be performed as a reference test in all consecutive patients, regardless of the degree of stenosis on the initial DUS test.

Imaging in endovascular therapy: our future

The endovascular therapist now has many modern imaging techniques available to plan and execute treatment, whereas in the past vascular surgeons relied mostly on clinical examination and arteriography. Advances in computer technology have enabled fast acquisition and processing of the large amounts of digital data essential to capture the dynamic information from fast-flowing blood at high resolution. Functional imaging has begun to play a role in predicting stability of progressive vascular disease and the need for and risks of intervention. Computing power now affords the interventionist the ability to handle imaging data in powerful 3-dimensional programs and electronically "in-lay" a variety of devices to plan complex endovascular procedures from the familiar platform of a laptop. In four major clinical areas, carotid intervention, peripheral intervention, endoluminal grafting, and cardiac imaging, we review the latest advances and changes with an eye toward how we should best be using imaging in our patients undergoing endovascular treatment...now and into the future.

Gadofosveset-enhanced MR angiography of carotid arteries: does steady-state imaging improve accuracy of first-pass imaging? Comparison with selective digital subtraction angiography

PURPOSE

To evaluate the diagnostic accuracy of gadofosveset-enhanced magnetic resonance (MR) angiography in the assessment of carotid artery stenosis, with digital subtraction angiography (DSA) as the reference standard, and to determine the value of reading first-pass, steady-state, and "combined" (first-pass plus steady-state) MR angiograms.

MATERIALS AND METHODS

This study was approved by the local ethics committee, and all subjects gave written informed consent. MR angiography and DSA were performed in 84 patients (56 men, 28 women; age range, 61-76 years) with carotid artery stenosis at Doppler ultrasonography. Three readers reviewed the first-pass, steady-state, and combined MR data sets, and one independent observer evaluated the DSA images to assess stenosis degree, plaque morphology and ulceration, stenosis length, and tandem lesions. Interobserver agreement regarding MR angiographic findings was analyzed by using intraclass correlation and Cohen kappa coefficients. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated by using the McNemar test to determine possible significant differences (P < .05).

RESULTS

Interobserver agreement regarding all MR angiogram readings was substantial. For grading stenosis, sensitivity, specificity, PPV, and NPV were, respectively, 90%, 92%, 91%, and 91% for first-pass imaging; 95% each for steady-state imaging; and 96%, 99%, 99%, and 97% for combined imaging. For evaluation of plaque morphology, respective values were 84%, 86%, 88%, and 82% for first-pass imaging; 98%, 97%, 98%, and 97% for steady-state imaging; and 98%, 100%, 100%, and 97% for combined imaging. Differences between the first-pass, steady-state, and combined image readings for assessment of stenosis degree and plaque morphology were significant (P < .001).

CONCLUSION

Gadofosveset-enhanced MR angiography is a promising technique for imaging carotid artery stenosis. Steady-state image reading is superior to first-pass image reading, but the combined reading protocol is more accurate.

Decision analysis to complete diagnostic research by closing the gap between test characteristics and cost-effectiveness

OBJECTIVE

The lack of a standard methodology in diagnostic research impedes adequate evaluation before implementation of constantly developing diagnostic techniques. We discuss the methodology of diagnostic research and underscore the relevance of decision analysis in the process of evaluation of diagnostic tests.

STUDY DESIGN AND SETTING

Overview and conceptual discussion.

RESULTS

Diagnostic research requires a stepwise approach comprising assessment of test characteristics followed by evaluation of added value, clinical outcome, and cost-effectiveness. These multiple goals are generally incompatible with a randomized design. Decision-analytic models provide an important alternative through integration of the best available evidence. Thus, critical assessment of clinical value and efficient use of resources can be achieved.

CONCLUSION

Decision-analytic models should be considered part of the standard methodology in diagnostic research. They can serve as a valid alternative to diagnostic randomized clinical trials (RCTs).

Treatment of carotid artery stenosis: medical therapy, surgery, or stenting?

With the aging of the general population and the availability of noninvasive imaging studies, carotid artery stenosis is a disease commonly seen in general medical practice. Differentiation between symptomatic and asymptomatic disease is critical to the treatment course because the natural history differs markedly between them. Antiplatelet therapy and aggressive treatment of vascular risk factors are the mainstays of medical therapy. Class I evidence shows that carotid endarterectomy (CEA) is effective in preventing ipsilateral ischemic events in patients with symptomatic moderate- and high-grade stenosis. The procedure is also effective in selected patients with asymptomatic stenosis, but the benefit is marginal. In the past decade, carotid angioplasty and stenting has been proposed as a valid alternative to CEA. Currently, it is unclear whether carotid angioplasty and stenting is as safe as CEA in patients with carotid artery stenosis who need invasive treatment. Large clinical trials are under way to answer this question.

High-resolution 3T MR angiography of the carotid arteries: comparison of manual and semiautomated quantification of stenosis

BACKGROUND AND PURPOSE

High-resolution contrast-enhanced MR angiography (CE-MRA) acquired at 3T exquisitely depict carotid artery (CA) stenosis. In this study, we examined the agreement of different vessel-analysis tools with manual quantitative measurement by 2 readers using CE-MRA data.

MATERIALS AND METHODS

Three vessel tools determining the trajectory of the vessel of interest and, subsequently, the vessel dimensions were tested against manual measurements. Diameter and area stenoses were calculated. CE-MRA data of 32 patients with CA stenosis were evaluated. The agreement between different measurements was assessed with kappa statistics after categorizing stenosis (<25%, 25%-49%, 50%-69%, 70%-99%, and 100%).

RESULTS

The mean grades of stenosis based on diameter measurements were 59% (readers) and 60%/56%/59% based on the analysis with tools A/B/C (P = 0.2-0.7). kappa values for agreement between readers and the vessel tools were 0.73/0.77/0.77 (tools A/B/C for all CAs) and 0.66/0.74/0.75 (for the symptomatic side). The mean grades of stenoses based on area measurements for tools A/B/C were 68%/63%/69% versus 58% for readers. Values from readers differed significantly from those for tools A and C (P < 0.01). kappa values for agreement between readers and the vessel tools were 0.66/0.55/0.64 (for all CAs) and 0.53/0.44/0.57 (for the symptomatic side).

CONCLUSIONS

The automated approach allows accurate assessment of vessel dimensions in MRA images at least for diameter measurements according to the North American Symptomatic Carotid Endarterectomy Trial criteria.

Imaging for neuro-ophthalmic and orbital disease - a review

A literature review was performed by content experts in neuro-ophthalmology and neuroradiology using a systematic English-language Medline search (1994-2008) limited to articles with relevance to neuro-ophthalmic and orbital imaging. The information covered in this review includes: (i) the basic mechanics, indications and contraindications for cranial and orbital computed tomography and magnetic resonance (MR) imaging; (ii) the utility and indications for intravenous contrast, (iii) the use of specific MR sequences; (iv) the techniques and ophthalmic indications for computed tomography/MR angiography and venography; and (v) the techniques and indications for functional MR imaging, positron emission tomography scanning and single photon emission computed tomography. Throughout the review accurate and timely communication with the neuroradiologist regarding the clinical findings and suspected location of lesions is emphasized so as to optimize the ordering and interpretation of imaging studies for the ophthalmologist.

Mandatory diagnostic angiography for carotid artery stenosis prior to carotid artery intervention

INTRODUCTION

Revascularization is an important strategy for reducing stroke risk in patients with severe carotid atherosclerosis. Magnetic resonance angiography (MRA) and/or carotid ultrasound have traditionally been used as the only diagnostic modalities prior to revascularization. Patients undergoing CEA frequently have no further assessments of carotid anatomy prior to surgery. Evaluation with carotid ultrasound and MRA can often overestimate the degree of stenosis. We sought to determine if noninvasive imaging was sufficient for determining whether a patient should be referred for carotid intervention.

METHODS

We performed an analysis of 101 patients referred for carotid artery stenting (CAS). All patients had previously been evaluated with carotid ultrasound and 94% had undergone MRA as well. We sought to determine if noninvasive diagnostic imaging for carotid stenosis was sufficient to determine the necessity for endovascular intervention.

RESULTS

Of the 101 patients referred for carotid intervention, 36 (36%) were shown to have <70% stenoses and did not require intervention. Of those who had significant disease, 49 (75%) underwent successful CAS, 15 (23%) underwent CEA, and 1 patient was treated medically for a total occlusion. Three of the 36 patients not requiring carotid intervention were found to have subclavian stenosis. Two (4%) of the patients undergoing CAS and 4 (27%) of the patients undergoing CEA had minor complications. No patients suffered a major stroke, MI, or death at follow-up.

CONCLUSION

This analysis demonstrates that 36% of patients referred for endovascular intervention based on noninvasive imaging did not meet criteria by angiography. This emphasizes the need for carotid angiography prior to carotid intervention.

Meta-analysis of diagnostic studies: a comparison of random intercept, normal-normal, and binomial-normal bivariate summary ROC approaches

BACKGROUND

Using data from a published meta-analysis of magnetic resonance imaging of the menisci and cruciate ligaments, the authors varied the overall sensitivity and specificity, the between-studies variance, the within-study sample size, and the number of studies to evaluate the performances of the 3 methods in a simulation study. The parameters to be compared are the associated intercept, slope, and residual variance, using bias, mean squared error, and coverage probabilities.

RESULTS

The BN method always gave unbiased estimates of the intercept and slope parameter. The coverage probabilities were also reasonably acceptable, unless the number of studies was very small. In contrast, the RI and NN methods could produce large biases with poor coverage probabilities, especially when sample sizes of individual studies were small or when sensitivities or specificities were close to 1. Although this was rare in the simulations, the bivariate methods can suffer from nonconvergence mostly due to the correlation being close to +/- 1.

CONCLUSION

The binomial-normal model performed better than the other recently introduced methods for meta-analysis of data from studies of test performance.

Transient ischemic attack: diagnostic evaluation

A transient ischemic attack portends significant risk of a stroke. Consequently, the diagnostic evaluation in the emergency department is focused on identifying high-risk causes so that preventive strategies can be implemented. The evaluation consists of a facilitated evaluation of the patient's metabolic, cardiac, and neurovascular systems. At a minimum, the following tests are recommended: fingerstick glucose level, electrolyte levels, CBC count, urinalysis, and coagulation studies; noncontrast computed tomography (CT) of the head; electrocardiography; and continuous telemetry monitoring. Vascular imaging studies, such as carotid ultrasonography, CT angiography, or magnetic resonance angiography, should be performed on an urgent basis and prioritized according to the patient's risk stratification for disease. Consideration should be given for echocardiography if no large vessel abnormality is identified.

Developments in neuroimaging for acute ischemic stroke: diagnostic and clinical trial applications

Over the past several years, active investigation into neuroimaging in the setting of acute ischemic stroke has improved our understanding of and ability to visualize the dynamic pathophysiology of acute cerebrovascular disease. Efforts surrounding the application of multimodal CT and MRI have resulted in a growing body of data from systematic evaluations of different parameters, experience in the use of these techniques in guiding clinical decision making, and clinical trials employing neuroimaging for patient selection, for proof of principle, and as a surrogate outcome measure.

Bivariate Random Effects Meta-Analysis of ROC Curves

Meta-analysis of receiver operating characteristic (ROC)-curve data is often done with fixed-effects models, which suffer many shortcomings. Some random-effects models have been proposed to execute a meta-analysis of ROC-curve data, but these models are not often used in practice. Straightforward modeling techniques for multivariate random-effects meta-analysis of ROC-curve data are needed. The 1st aim of this article is to present a practical method that addresses the drawbacks of the fixedeffects summary ROC (SROC) method of Littenberg and Moses. Sensitivities and specificities are analyzed simultaneously using a bivariate random-effects model. The 2nd aim is to show that other SROC curves can also be derived from the bivariate model through different characterizations of the estimated bivariate normal distribution. Thereby the authors show that the bivariate random-effects approach not only extends the SROC approach but also provides a unifying framework for other approaches. The authors bring the statistical meta-analysis of ROC-curve data back into a framework of relatively standard multivariate meta-analysis with random effects. The analyses were carried out using the software package SAS (Proc NLMIXED).

Guidelines for management of ischaemic stroke and transient ischaemic attack 2008

This article represents the update of the European Stroke Initiative Recommendations for Stroke Management. These guidelines cover both ischaemic stroke and transient ischaemic attacks, which are now considered to be a single entity. The article covers referral and emergency management, Stroke Unit service, diagnostics, primary and secondary prevention, general stroke treatment, specific treatment including acute management, management of complications, and rehabilitation.

Carotid Imaging for Secondary Stroke Prevention in Routine Practice

Carotid imaging is key to effective secondary stroke prevention. It is commonly performed, but is a rather specialist procedure requiring regular practice to maintain acceptable accuracy. Previously the domain of the neuroradiologist, noninvasive carotid imaging is now widely practiced in general departments where specialist knowledge of anatomy and intracranial disorders may be less available. Noninvasive imaging is largely replacing intraarterial angiography in the assessment of carotid stenosis in most centres because the accuracy is perceived to be sufficient. However, effective stroke prevention needs to be delivered rapidly, guided by imaging tests that are used with an understanding of their limitations and accuracy. This review will discuss currently available imaging methods, their advantages and disadvantages, difficulties in determining their accuracy, current estimates of accuracy and gaps in knowledge.

Introduction: Stroke is common, has a poor outcome, and treatment must be delivered quickly. Many pharmacological acute stroke treatments have failed, reinforcing the need for effective prevention. There has been extensive testing of many pharmacological secondary prevention treatments and most of the ‘positive’ stroke trials have been in secondary prevention of ischaemic stroke. The surgical procedures for stroke prevention, carotid endarterectomy and angioplasty, have also been subjected to far closer scrutiny in large randomised-controlled trials than almost any other surgical or interventional radiological procedures. However, it is unfortunate that much of the focus of secondary stroke prevention has been on drug mechanisms, or surgery vs. endovascular methods, rather than on how to identify accurately and quickly the right patients for each intervention. Thus, until fairly recently ( 1 , 2 ), the need for very rapid initiation of medical and surgical interventions in patients whose carotid stenosis has been accurately diagnosed by imaging ( 3 ), and the service modifications required to deliver this ( 4 ), have largely been overlooked.

Outcome analysis of carotid artery occlusion

The outcome of carotid artery occlusion was studied through the retrospective identification of 115 affected patients. The majority were white (77%) males (61%) with multiple atherogenic risk factors and suffering ipsilateral stroke (57%). Those patients presenting with stroke were not distinguished by demographic features, risk factors, lipid profile, medical regimen, or subsequent mortality when compared with those without. Overall, 36 patients (31%) required contralateral carotid endarterectomy (CEA), with one (2.8%) perioperative stroke, whereas 4 (3%) underwent ipsilateral external CEA without incident. With 81% follow-up (mean 3.9 years), the overall mortality of the group was 46%; the annualized risk of ipsilateral stroke was 1.6%. This study documents a significant risk of stroke and contralateral occlusive disease with ipsilateral carotid artery occlusion, which cannot be reliably predicted by clinical criteria. Duplex surveillance is valuable, but flow velocity measurements alone may be misleading. Surgical endarterectomy can be performed with an acceptable rate of perioperative stroke.

Advances in vascular imaging

Advances in vascular surgery have mirrored advances in diagnostic imaging. Indeed, the endovascular revolution has been made possible largely by advances in computed tomography, magnetic resonance imaging, and vascular ultrasound. As technology allows better noninvasive vascular diagnosis, conventional angiography, once the gold standard for the diagnosis of vascular disease, is now reserved largely for intervention. This article discusses the current state of vascular imaging. Specific emphasis is placed on the comparative clinical utility of different imaging modalities in the detection and management of vascular disease.