The management of carotid stenosis has been based on major prospective trials that have used arteriography. However, noninvasive methods of evaluation have been sought because angiography has a significant risk of major complications and a high cost. Availability, low cost, and high diagnostic accuracy make duplex ultrasound the first line of investigation when carotid disease is suspected. Duplex ultrasound is limited by operator and machine variability. Magnetic resonance angiography in coordination with duplex ultrasound has increased accuracy and should be done after an equivocal or inadequate duplex ultrasound exam. Magnetic resonance angiography accuracy has improved with the use of contrast and threedimensional time-of-flight techniques over a two-dimensional time-of-flight method. Computed tomographic angiography can also validate the duplex ultrasound exam and give additional information for the arch and intracranial vessels. Axial reconstruction has shown the greatest accuracy. Future studies defining the prognosis of area stenosis, plaque volume, and composition will further improve treatment that is based on noninvasive imaging.
1.North American Symptomatic Carotid Endarterectomy Trial Collaborators: Beneficial effect of carotid endarterectomy in symptomatic patients with highgrade stenosis. N Engl J Med325:445-453, 1991.
2.
2.European Carotid Surgery Trialists' Collaborative Group: MRC European Carotid Surgery Trial: Interim results for symptomatic patients with severe (70- 99%) or with mild (0-29%) carotid stenosis. Lancet337:1235-1243, 1991.
3.
3.Endarterectomy for asymptomatic carotid artery stenosis: Executive Committee for ACAS Study. JAMA273:1421-1428, 1995.
4.
4.Barnett HJ, Taylor DW, Eliasziw M: Benefit of carotid endarterectomy in patients with symptomatic moderate or severe stenosis. N Engl J Med339:1415-1425, 1998.
5.
5.Hankey GJ, Warlow CP, Molyneux AJ: Complications of cerebral angiography for patients with mild carotid territory ischaemia being considered for carotid endarterectomy. J Neurol Neurosurg Psychiatry53:542-548, 1990.
6.
6.Davies KN, Humphrey PR: Complications of cerebral angiography in patients with symptomatic carotid territory ischaemia screened by carotid ultrasound. J Neurol Neurosurg Psychiatry56:967-972, 1993.
7.
7.Johnston DC, Chapman KM., Goldstein LB: Low rate of complication of cerebral angiography in routing clinical practice. Neurology57:2012-2014,2001.
8.
8.Schwartz SW, Chambless LE, Baker WH, et al: Related articles consistency of Doppler parameters in predicting arteriographically confirmed carotid stenosis. Asymptomatic Carotid Atherosclerosis Study Investigators. Stroke28:343-347, 1997.
9.
9.Logason K, Sadettin K, Ulus AT, et al: The impact of different spectral Doppler criteria on the proportion of high-grade internal carotid artery stenosis in patients undergoing duplex scanning. Angiology53:297-301,2001.
10.
10.Hwang CS, Shau WY, Tegeler CH: Doppler velocity criteria based on receiver operating characteristic analysis for the detection of threshold carotid stenosis. J Neuroimaging12:124-130,2002.
11.
11.Elgersma OE, van Leersum M, Buijs PC, et al: Changes over time in optimal duplex threshold for the identification of patients eligible for carotid endarterectomy. Stroke29:2352-2356, 1998.
12.
12.Moneta G, Edwards J, Chitwood R, et al: Correlation of North American Symptomatic Carotid Endarterectomy Trial (NASCET) angiographic definition of 70% to 99% internal carotid artery stenosis with duplex scanning. J Vasc Surg17:152-159, 1993.
13.
13.Young GR, Humphrey PR, Shaw MD, et al: Comparison of magnetic resonance angiography, duplex ultrasound, and digital subtraction angiography in assessment of extracranial internal carotid artery stenosis. J Neurol Neurosurg Psyhiatry57:1466-1478, 1994.
14.
14.Kent KC, Kuntz KM, Patel MR, et al: Perioperative imaging strategies for carotid endarterectomy: An analysis of morbidity and cost-effectiveness in symptomatic patients. JAMA274:888-893, 1995.
15.
15.Patel MR, Kuntz KM, Klufas RA, et al. Preoperative assessment of the carotid bifurcation: Can magnetic resonance angiography and duplex ultrasonography replace contrast arteriography?Stroke26:1753-1758, 1995.
16.
16.Srinivasan J, Mayberg MR, Weiss DG, et al: Duplex accuracy compared with angiography in the Veterans Affairs Cooperative Studies Trial for Symptomatic Carotid Stenosis. Neurosurgery36:648-653, 1995.
17.
17.Hood DB, Mattos MA, Mansour A, et al: Prospective evaluation of new duplex criteria to identify 70% internal carotid artery stenosis. J Vasc Surg1996;23:254-261.
18.
18.Alexandrov AV, Vital D, Brodie DS, et al: Grading carotid stenosis with ultrasound. An interlaboratory comparison. Stroke28:1208-1210, 1997.
19.
19.Jackson MR, Chang AS, Robles HA, et al: Determination of 60% or greater carotid stenosis: a prospective comparison of magnetic resonance angiography and duplex ultrasound with conventional angiography. Ann Vasc Surg12:236-243, 1998.
20.
20.Huston J, Nichols DA, Luetmer PH, et al: MR angiographic and sonographic indications for endarterectomy. AJNR19:309-315, 1998.
21.
21.AbuRahma A, Robinson P, Strickler D, et al: Proposed new duplex classification for threshold stenoses used in various symptomatic and asymptomatic carotid endarterectomy trials. Ann Vasc Surg12:349-358, 1998.
22.
22.Belsky M, Gaitini D, Goldsher D, et al: Color-coded duplex ultrasound compared to CT angiography for detection and quantification of carotid artery stenosis. Eur J Ultrasound12:49-60,2000.
23.
23.Anderson GB, Ashforth R, Steinke DE, et al: CT angiography for the detection and characterization of carotid artery bifurcation disease. Stroke31:2168-2174, 2000.
24.
24.Back MR, Wilson JS, Rushing G, et al: Magnetic resonance angiography is an accurate imaging adjunct to duplex ultrasound scan in patient selection for carotid endarterectomy. J Vasc Surg32:429-440, 2000.
25.
25.Bingahi S, Maeder P, Uske A, et al: Three-dimensional computed tomography angiography and magnetic resonance angiography of carotid bifurcation stenosis. Eur Neurol46:25-34, 2001.
27.Nederkoorn PJ, Mali WP, Eikelboom BC, et al: Preoperative diagnosis of carotid artery stenosis: accuracy of noninvasive testing. Stroke33:2003-2008,2002.
28.
28.MacKenzie KS, French-Sherry E, Burns K, et al: Bmode ultrasound measurement of carotid bifurcation stenoses: is it reliable?Vasc Endovasc Surg36:123-135,2002.
29.
29.Patel SG, Collie DA, Wardlaw JM, et al: Outcome, observer reliability, and patient preferences if CTA, MRA, or Doppler ultrasound were used, individually or together, instead of digital subtraction angiography before carotid endarterectomy. J Neurol Neurosurg Psychiatry73:21-28,2002.
30.
30.Steinke W, Ries S, Artemis N, et al: Power Doppler imaging of carotid artery stenosis: comparison with color Doppler flow imaging and angiography. Stroke28:1981-1987, 1997.
31.
31.Labropoulos N, Androulakis A, Allan R, et al: The value of colour flow duplex imaging in the detection of subtotal and total internal carotid artery occlusion. Vasc Surg31:775-779, 1997.
32.
32.Ascher E, Markevich N, Hingorani A, Kallakuri S: Pseudo-occlusions of the internal carotid artery: a rationale for treatment on the basis of a modified carotid duplex scan protocol. J Vasc Surg35:340-345, 2002.
33.
33.Archie JP Jr: Carotid endarterectomy when the distal internal carotid artery is small or poorly visualized. J Vasc Surg19:23-30, 1994.
34.
34.Fredericks RK, Thomas TD, Lefkowitz DS, et al: Implications of the angiographic string sign in carotid atherosclerosis. Stroke21:476-479, 1990.
35.
35.Gabrielson TO, Seeger JF, Knake JE, et al: The nearly occluded internal carotid artery: A diagnostic trap.Radiology138:611-618, 1981.
36.
36.Berman SS, Bernhard VM, Erly WK, et al: Critical carotid artery stenosis: Diagnosis, timing of surgery, and outcome.J Vasc Surg20:499-508, 1994.
37.
37.Mehigan JT, Olcott C IV: The carotid "string" sign.Differential diagnosis and managementAm J Surg140:137-143, 1980.
38.
38.Westwood ME, Kelly S, Berry E, et al: Use of magnetic resonance angiography to select candidates with recently symptomatic carotid stenosis for surgery: Systemic review.BMJ324:1-5, 2002.
39.
39.Mittl RL, Broderick M, Carpenter JP, et al: Blindedreader comparison of magnetic resonance angiography and duplex ultrasonography for carotid artery bifurcation stenosis.Stroke25:4-10, 1994.
40.
40.Anderson C, Lee R, Levin D, et al: Measurement of internal carotid artery stenosis from source MR angiograms.Radiology193:219-226, 1994.
41.
41.Magarelli N, Scarabino T, Simeone AL, et al: Carotid stenosis: A comparison between MR and spiral CT angiography.Neuroradiology1998;40:367-373.
42.
42.Serfaty JM, Chirossel P, Chevallier JM, et al: Accuracy of three-dimensional gadolimium-enhanced MR angiography in the assessment of extracranial carotid artery disease.AJR175:455-463, 2000.
43.
43.Nederkoorn PJ, Elgersma OE, Mali WP, et al: Overestimation of carotid artery stenosis with magnetic resonance angiography compared with digital subtraction angiography.J Vasc Surg36:806-813, 2002.
44.
44.Remonda L, Heid O, Schroth G: Carotid artery stenosis, occlusion, and pseudo-occlusion: First-pass, gadolinium-enhanced, three-dimensional MR angiography-preliminary study.Radiology209:95-102, 1998.
45.
45.Randoux B, Marro B, Koskas F, et al: Carotid artery stenosis: Prospective comparison of CT, three-dimensional gadolinium-enhanced MR, and conventional angiography.Radiology220:179-185,2001.
46.
46.Sundgren PC, Sunden P, Lindgren A, et al: Carotid artery stenosis: Contrast-enhanced MR angiography with two different scan times compared with digital subtraction angiography.Neuroradiology44:592-599, 2002.
47.
47.Hirai T, Korogi Y, Ono K, et al: Prospective evaluation of suspected stenoocclusive disease of the intracranial artery: Combined MR angiography and CT angiography compared with digital subtraction angiography.Am J Neuroradiol23:93-101, 2002.
48.
48.Remonda L, Senn P, Alain B, et al: Contrast-enhanced 3D MR angiography of the carotid artery: Comparison with conventional digital subtraction angiography.Am J Neuroradiol23:213-219, 2002.
49.
49.Wutke R, Lang W, Fellner C, et al: High-resolution, contrast-enhanced magnetic resonance angiography with elliptical centric k-space ordering of supra-aortic arteries compared with selective x-ray angiography.Stroke33:1522-1529, 2002.
50.
50.Barbier C, LefEvre F, Bui P, et al: Contrast-enhanced MRA of the carotid arteries using 0.5 Tesla: Comparison with selective digital angiography.J Radiol82:245-249, 2001.
51.
51.Morasch MD, Gurjala AN, Washington E, et al.Crosssectional magnetic resonance angiography is accurate in predicting degree of carotid stenosis.Ann Vasc Surg16:266-272, 2002.
52.
52.Elgersma OE, Wust AF, Buijs PC, et al: Multidirectional depiction of internal carotid arterial stenosis: three-dimensional time-of-flight MR angiography versus rotational and conventional digital subtraction angiography.Radiology216:511-516, 2000.
53.
53.Nederkoorn PJ, Elgersma OE, Mali WP, et al: Overestimation of carotid artery stenosis with magnetic resonance angiography compared with digital subtraction angiography.J Vasc Surg36:806-813, 2002.
54.
54.Pan XM, Saloner D, Reilly LM, et al: Assessment of carotid artery stenosis by ultrasonography, conventional angiography, and magnetic resonance angiography: Correlation with ex vivo measurement of plaque stenosis.J Vasc Surg21:82-89, 1995.
55.
55.Keller P: Time-of-flight magnetic resonance angiography.Neuroimag Clin N Am4:639-656, 1992.
56.
56.Leclerc X, Godefroy O, Pruvo JP, et al: Computed tomographic angiography for the evaluation of carotid artery stenosis.Stroke26:1577-1581, 1995.
57.
57.Moll R, Dinkel HP: Value of the CT angiography in the diagnosis of common carotid artery bifurcation disease: CT angiography versus digital subtraction angiography and color flow Doppler.Eur J Rad39:155-162, 2001.
58.
58.Dillon EH, van Leeuwen MS, Fernandez MA, et al: CT angiography: application to the evaluation of carotid artery stenosis.Radiology189:211-219, 1993.
59.
59.Simeone A, Carriero A, Armillotta M, et al: Spiral CT angiography in the study of the carotid stenosis.J Neuroradiol24:18-22, 1997.
60.
60.Cinat M, Lane CT, Pham H, et al: Helical CT angiography in the preoperative evaluation of carotid artery stenosis.J Vasc Surg28:290-300, 1998.
61.
61.Dorsch NWC, Young N, Kingston RJ, et al: Early experience with spiral CT in the diagnosis of intracranial aneurysms.Neurosurgery36:230-238, 1995.
62.
62.Harrison MJ, Johnson BA, Gardner GM, et al: Preliminary results on the management of unruptured intracranial aneurysms with magnetic resonance angiography and computed tomographic angiography.Neurosurgery40:947-957, 1997.
63.
63.Hope JKA, Wilson JL, Thomson FJ: Three-dimensional CT angiography in the detection and characterization of intracranial berry aneurysms.Am J Neuroradiol17:439-445, 1996.
64.
64.Hsiang JNK, Liang EY, Lam JMK, et al: The role of computed tomographic angiography in the diagnosis of intracranial aneurysms and emergent aneurysm clipping.Neurosurgery38:481-487, 1996.
65.
65.Zouaoui A, Sahel M, Marro B, et al: Three-dimensional computed tomographic angiography in detection of cerebral aneurysms in acute subarachnoid hermorrhage.Neurosurgery41:125-130, 1997.
66.
66.Sameshima T, Futami S, Morita Y, et al: Clinical usefulness of and problems with three-dimensional CT angiography for the evaluation of arteriosclerotic stenosis of the carotid artery: comparison with conventional angiography, MRA, and ultrasound sonography.Surg Neurol51:300-309, 1999.
67.
67.Takahashi M, Ashtari M, Papp Z, et al:CT angiography of carotid brifurcation. Am J Rad813-817, 1996.
68.
68.Turnipseed WD, Kennell TW, Turski PA, et al: Combined use of duplex imaging and magnetic resonance resonance angiography for evaluation of patients with symptomatic ipsilateral high-grade carotid stenosis.J Vasc Surg17:832-840, 1993.
69.
69.Kuntz KM, Skillman JJ, Whittemore AD, et al: Carotid endarterectomy in asymptomatic patients-is contrast angiography necessary? A morbidity analysis.J Vasc Surg22:706-714, 1995.
