Evaluation of Classic 2D Time-of-Flight MR Angiography in the Depiction of Severe Carotid Stenosis

Management of extracranial carotid artery disease

Stroke is the third leading cause of death in developed nations. Up to 88% of strokes are ischemic in nature. Extracranial carotid artery atherosclerotic disease is the third leading cause of ischemic stroke in the general population and the second most common nontraumatic cause among adults younger than 45 years. This article provides comprehensive, evidence-based recommendations for the management of extracranial atherosclerotic disease, including imaging for screening and diagnosis, medical management, and interventional management.

Non-Invasive Carotid Imaging: A Comparative Assessment and Practical Approach

Stroke originating from carotid artery disease remains a significant source of morbidity and mortality, and both medical and invasive therapies targeting the carotid artery can improve patient outcomes. Multiple noninvasive imaging methods, including duplex ultrasonography, computerized tomographic angiography, and magnetic resonance angiography, are available to assess the extracranial carotid artery and guide clinical decision making. This article discusses the advantages and limitations of these imaging modalities and provides a practical framework by which clinicians may use imaging to evaluate patients with carotid artery disease.

Diagnosis and management of calcified carotid artery atheroma: dental perspectives

The calcification of cervical carotid artery atheroma (CCAA) represents maturation of a lumenal atherosclerotic plaque that has been associated with a high risk of cerebral stroke. The demonstration of CCAA on rotational panoramic images has received increasing attention in dentistry since it was first described in 1981. The purposes of this article are to provide a background to the mechanism of arterial calcification, to review the clinical diagnostic and management algorithms for dental practitioners when CCAA are identified radiologically, and to describe and illustrate current appropriate radiographic modalities and medical management strategies used to confirm and assess stenosis associated with CCAA.

Magnetic resonance angiography of the extracranial carotid system

OBJECTIVES

To discuss the role of magnetic resonance angiography (MRA) in the evaluation of the extracranial carotid system with an emphasis on atherosclerosis and to briefly address the role of magnetic resonance imaging in imaging of carotid atherosclerotic plaque.

METHODS

Literature and institutional review.

DISCUSSION

The North American Symptomatic Carotid Endarterectomy Trial and European Carotid Surgery Trial studies have emphasized the importance of recognition and treatment of carotid stenosis in the prevention of ischemic stroke. Magnetic resonance angiography is a viable tool in the screening and quantification of this entity. Both time of flight and contrast-enhanced MRA techniques are available for clinical use, each with distinct advantages and limitations. A thorough understanding of these is vital for correct performance and interpretation of these studies. Plaque imaging with magnetic resonance imaging offers new insights into the pathophysiology of the atherosclerotic process and may be used in the future to monitor response to lipid-lowering drug therapy.

CONCLUSION

Magnetic resonance angiography is a robust imaging technique for evaluation of the extracranial carotid circulation. The radiologist must be aware of the advantages and limitations of the different techniques available. Contrast-enhanced MRA is now the most widely performed technique. It can be used to replace digital subtraction angiography in the evaluation of carotid stenosis in most clinical settings.

Imaging of the carotid arteries: the role of duplex ultrasonography, magnetic resonance arteriography, and computerized tomographic arteriography

Stenosis of the internal carotid artery represents a major cause of stroke, with atherosclerosis representing the major pathophysiology of this stenosis. It is estimated that over 700,000 Americans suffer a stroke annually. A prompt and accurate diagnosis of carotid artery disease is critical when planning a therapeutic strategy. Physical examination is inaccurate in determining the presence and severity of carotid artery disease. Therefore, reliable imaging tests which offer little risk to the patient are required.

Specificity of MR Angiography as a Confirmatory Test for Carotid Artery Stenosis: Is It Valid?

OBJECTIVE

We believe that many studies in the literature show a falsely elevated specificity for carotid MR angiography (MRA) in the detection of high-grade stenosis. The purpose of this study was to test the hypothesis that inclusion of a substantial proportion of normal carotid arteries in a study population will falsely elevate the specificity of MRA for confirming a high-grade carotid artery stenosis.

MATERIALS AND METHODS

Seventy-seven carotid arteries were evaluated in 63 patients suspected of having a high-grade carotid stenosis, and all vessels were evaluated with contrast-enhanced MRA. Two subgroups were created, and the specificity of MRA was calculated for each group using digital subtraction angiography (DSA) as the gold standard. Group 1 included 44 vessels classified as high-grade stenosis on sonography and all were evaluated with DSA. To test our hypothesis, group 2 included the 44 carotid arteries from group 1 plus 33 carotid arteries classified as normal or minimally narrowed on sonography and MRA.

RESULTS

In group 1, the specificity of MRA for accurately confirming a high-grade stenosis was 29% for contrast-enhanced maximum-intensity-projection (MIP) images alone and 75% for contrast-enhanced axially reformatted source images as compared with DSA. When the 33 normal arteries from group 2 were added to the data set, the specificities increased to 70% and 89%, respectively.

CONCLUSION

The calculated specificity of MRA as a confirmatory test for high-grade carotid stenosis is highly dependent on the proportion of normal carotid arteries included in the calculation. Based on our results, the specificity of MRA reported in the literature has likely been overstated because of spectrum bias.

Practical noninvasive neurovascular imaging of the neck arteries in patients with stroke, transient ischemic attack, and suspected arterial disease that may lead to ischemia, infarction, or flow abnormalities

Stroke is the third leading cause of death in the United States, killing nearly 157,000 people a year with an estimated society cost of dollar 58 billion in 2006. A large percentage of ischemic strokes is secondary to extracranial carotid and vertebral arterial disease. While digital subtraction angiography has traditionally been used for the initial evaluation of the degree of stenosis, noninvasive imaging has moved to the forefront in the extracranial arterial evaluation. The importance of understanding the imaging techniques, findings, interpretation, artifacts, and pitfalls is essential to appropriate patient management.

Utility of MRA and CTA in the evaluation of carotid occlusive disease

Cervical carotid artery atherosclerotic disease is an important cause of thromboembolic stroke. Noninvasive imaging techniques have become preferred in initial diagnostic workup. We review the current approach to carotid imaging, and the clinical utility and limitations of carotid computed tomography angiography (CTA) and magnetic resonance angiography (MRA). Future directions of these modalities, including carotid plaque imaging, are also discussed.