Indian Journal of Radiology Indian Journal of Radiology  

   Login   | Users online: 2048

Home Bookmark this page Print this page Email this page Small font sizeDefault font size Increase font size     

 

VASCULAR IMAGING Table of Contents   
Year : 2005  |  Volume : 15  |  Issue : 1  |  Page : 91-98
Color and duplex doppler imaging evaluation of extracranial carotid artery in patients presenting with transient ischaemic attack and stroke : a clinical and radiological correlation.


Lady Hardinge Medical College and Associated Hospitals, New Delhi, India

Click here for correspondence address and email
 

   Abstract 

OBJECTIVES -Present study was done to evaluate carotid artery disease by color and duplex imaging in 63 patients (126 vessels) presenting with transient ischaemic attack and stroke. METHODS Vessel wall thickness and plaque characterization were done by gray scale ultrasound and site and severity of stenosis was assessed on color and duplex Doppler. Doppler finding were correlated with clinical presentation, risk factors, CT and echocardiographic findings. RESULTS-Male sex (p<0.01), post menopausal state (p<0.05) Presence of hypertension (p<0.01), systolic blood pressure, smoking (p<0.05), diabetes mellitus (p<0.05), history suggestive of peripheral arterial disease (p<0.01), previous CVA (p<0.01) were determined to be statistically significant risk factors. All the patients with a carotid bruit had abnormal carotid Doppler. Mean cholesterol levels in patients with normal carotid arteries was 186.52 ( 36.88) mg% and mean cholesterol level in patients with carotid lesion was 219.11( 35.13) All patients with >40% stenosis had a cortical infarct, none of patients with >40% stenosis had a subcortical infarct. All 22 patients with sub cortical infarcts had either normal extra-cranial carotids or had <40% stenosis. . Majority of plaques (50%) in the present study were located at the bifurcation. Color Flow imaging showed a definite advantage over B-mode scanning in identification of the hypoechoic plaques and in identification of plaque ulcerations. The overall perfect agreement between Color Doppler Flow Imaging and Conventional Duplex scanning was 96.8%. In patients with complete occlusion findings of color flow imaging and spectral analysis were confirmed on power Doppler imaging. Mean IM thickness of patients with normal echocardiography was 0.9250 ( 0.2863) and IM thickness of patients with echocardiographic evidence of IHD was 1.3455 ( 0.2734). CONCLUSION-As progression of the atherosclerotic disease can be stopped by reducing the risk factors and critical (>70%) stenosis treated surgically present study highlights the importance of doppler imaging in stroke prevention through surveillance for atherosclerosis that predisposes a person to cerebral ischaemia.

Keywords: Atherosclerosis, Carotid Artery, Ultrasound, Doppler

How to cite this article:
Sethi S K, Solanki R S, Gupta H. Color and duplex doppler imaging evaluation of extracranial carotid artery in patients presenting with transient ischaemic attack and stroke : a clinical and radiological correlation. Indian J Radiol Imaging 2005;15:91-8

How to cite this URL:
Sethi S K, Solanki R S, Gupta H. Color and duplex doppler imaging evaluation of extracranial carotid artery in patients presenting with transient ischaemic attack and stroke : a clinical and radiological correlation. Indian J Radiol Imaging [serial online] 2005 [cited 2019 Nov 22];15:91-8. Available from: http://www.ijri.org/text.asp?2005/15/1/91/28756

   Introduction Top


Cerebrovascular insufficiency is the leading cause of mortality and morbidity all over the world. Lesions of the extracranial carotid arteries, particularly the internal carotid artery near the bifurcation, are implicated in majority of cases of cerebrovascular disorders [1]. The North American Symptomatic Carotid Endarterectomy Trial (NASCET) and European Carotid Surgery Trialists' Collaborative Group (ECST) showed a benefit of carotid endarterectomy for recently symptomatic patients with internal carotid lumen diameter narrowing of 70% or more [2]. At present Doppler is the main non-invasive imaging technique, widely available, with sensitivity approaching that of angiography [3] Clinical studies have suggested that an accurate evaluation of carotid occlusive disease may be possible non-invasively through a combination of MRA and ultrasound examinations of the carotid arteries [4],[5]. Hence, the present study was done to study the color and duplex imaging features of extracranial carotid artery in patients presenting with clinical features of TIA and stroke.


   Material and methods Top


This study was carried out using a real time ultrasound equipment capable of B-mode imaging, pulsed wave duplex scanning, color Doppler flow imaging and power Doppler imaging (HDI 5000 system, ATL ultrasound Inc.). All patients of adult age group presenting with clinical features of stroke or patients presenting with history suggestive of transient ischaemic attacks were taken up for the study. Detailed clinical history was taken from each patient. This included -Age, Sex, Pre/Post menopausal state and Risk Factors including Hypertension,Diabetes Mellitus,H/S/O CAD, Smoking, Alcohol intake,Previous stroke or TIA,Peripheral arterial disease,Hyperlipidemia (S.cholesterol, triglyceride levels). A detailed Cardiovascular and, Neurological examination was done Investigations like postero-anterior radiograph of chest, Computed tomography of head, Echocardiography were carried out.


   Doppler technique Top



   Visual inspection of gray scale images Top


Vessel wall thickness -Thickening of I-M complex greater than 0.8mm was considered abnormal [6],[7] [Figure - 1][Figure - 2]

Plaque characterization -Plaque texture was classified as being hypoechoic,echogenic or calcified..

The uniform hyperechoic acoustic texture corresponds pathologically to dense, fibrous, connective tissue. Calcified plaque produces posterior acoustic shadowing and is common in asymptomatic individuals. Hypoechoic plaque is characterized pathologically by containing deposits of lipid and cholesterol [6].

Doppler measurements were obtained in the stenotic portion of the carotid lumen.

Parameters measured included [8]: -

1. Peak systolic velocity (PSV)

2. Peak end diastolic velocity (EDV)

3. Systolic and diastolic ratios

Carotid occlusion was diagnosed by-Absence of arterial pulsations, occlusion of lumen by echogenic material, absence of Doppler flow signals, and subnormal vessel size (chronic occlusion).

Statistical analysis was carried out using Z-test, chi-square test (using Yates correction) and student's t-test. Results of Color Doppler Flow Imaging, Duplex scanning were compared and perfect agreement between these was calculated. Data analysis was done with statistical package for social sciences (SPSS) In this study, p<0.05 was considered as statistically significant.


   Results Top


A total number of 66 patients were studied. Three patients were excluded from the study (n=1 high carotid bifurcation, which limited proper evaluation of internal carotid artery, and n=2 extensive calcification of plaque, which interfered with imaging). Thus the total number of patients included in this study was reduced to 63 (126 vessels).


   Age distribution Top


The mean age of patients without any carotid lesion was 48.83 ( 15.27) years and mean age of patients with carotid lesion was 60.03 ( 11.29) years.

SEX Out of 29 men 18 (62%) had a carotid lesion and out of 34 women eight (23%) had a carotid lesion (p<0.01) SMOKING Out of 10 smokers five (50%) had <40% stenosis, two (20%) had >40% stenosis and one (10%) had total occlusion (p<0.05).

HYPERTENSION Of 35 hypertensives 17 (48.6%) were normal, 15 (42.8%) had stenosis less than 40%, two (5.7%) had stenosis greater than 40% and one (2.8%) had complete occlusion. (p<0.01) Mean systolic blood pressure in patients with normal carotids was 148( 28.56) and in patients with carotid lesion was 162( 24.46)

DIABETES MELLITUS Of 16 diabetics five (31.25%) were normal, eight (50%) had <40% stenosis, two (12.5%) had >40% stenosis and one (6.25%) had complete occlusion. (p<0.05).

PERIPHERAL ARTERIAL DISEASE Six patients (9.5%) had PVD (history of intermittent claudication, non-healing ulcers etc.). Of six patients with PVD two (33.3%) had <40% stenosis, three (50%) had >40% stenosis and one (16.7%) had complete occlusion. None of the patients had normal carotid arteries. (p<0.01).

CAROTID BRUIT Four patients had clinical evidence of carotid bruit. Out of 4, 3 had >40% stenosis and 1 had <40% stenosis, none of the patients with carotid bruit had normal carotid arteries.

POST-MENOPAUSAL WOMEN Out of 23 postmenopausal women 14 (60.86%) were normal, seven (30.43%) had stenosis <40%, one (4.34%) had stenosis >40% and one (4.34%) had complete occlusion. All 11 of premenopausal women had normal carotid arteries. (p<0.05).

PREVIOUS CEREBROVASCULAR ACCIDENT Of 15 patients with previous CVA 3 (20%) were normal, seven (46.7%) had <40% stenosis, four (26.7%) had stenosis greater than 40% and one (6.6%) had complete occlusion. (p<0.01).

CORONARY HEART DISEASE 12 patients (19.04%) had history suggestive of CAD. Out of these 12, five (41.66%) were normal, three (25%) had stenosis <40%, three (25%) had stenosis > 40% and one (8.33%) had complete occlusion.

Cholesterol levels in the study group ranged from 129 to 296mg%. Mean cholesterol levels in patients with normal carotid arteries was 186.52( 36.88) mg% and mean cholesterol level in patients with carotid lesion was 219.11( 35.13). [Statistically significant (student's t-test)].

All patients with >40% stenosis had a cortical infarct, none of patients with >40% stenosis had a subcortical infarct. All 22 patients with subcortical infarcts had either normal extracranial carotids or had <40% stenosis. These subcortical infarcts were probably caused by obstruction of deep penetrating vessels by lipohyalinosis and microatheromatosis producing a distal hemodynamic compromise and lacunae [9,10]. Four patients with RHD also had cortical infarcts.


   Plaque characterstics Top


A total of 36 plaques were observed out of which 19 (53%) were echogenic, 13 (36%) were calcified and 4 (11%) were hypoechoic. Two of the vessels were completely occluded. Ulceration was not detected on B-mode in any of the plaques.


   Ulceration Top


On B-mode imaging no ulceration was observed. On color flow imaging two of the plaques showed evidence of ulceration. 5.5% of plaques showed evidence of ulceration on color flow imaging


   Plaque location Top


Of the 36 plaques 11 were located in common carotid artery, 7 in internal carotid artery and 18 at the bifurcation. Overall 50% of the plaques were located at the bifurcation, 19.4% in internal carotid and 30.6% in the common carotid artery.


   Color flow imaging vs conventional duplex scanning Top


One twenty six vessels were compared on spectral waveform analysis and color flow imaging.

Of which 90 vessels were classified as no stenosis by spectral waveform analysis, 88 of these cases were confirmed on color flow imaging. Two vessels were classified as no stenosis by conventional duplex scanning were classified as 1-39% stenosis by color flow imaging. Hypoechoic plaque was missed on B-mode imaging. Both color and spectral waveform analysis similarly classified four vessels in 40-59% stenosis group. Both Color and spectral waveform analysis respectively similarly classified two vessels, one each in 60-79% and 80-99% stenosis group. [Figure - 3][Figure - 4][Figure - 5][Figure - 6]

Color flow imaging diagnosed two vessels as completely occluded, both of which were assigned same stenosis category by duplex imaging. [Figure - 7][Figure - 8][Figure - 10]

The overall perfect agreement between Color Flow Imaging and conventional duplex scanning was 96.8%.


   Power doppler imaging Top


Power Doppler was used in two patients with complete occlusion on conventional duplex scanning and color flow imaging. In both patients findings of color flow imaging and spectral analysis were confirmed on power Doppler imaging. [Figure - 9]


   IM THICKNESS- AN INDICATOR OF ISCHAEMIC HEART DISEASE? Top


IM Thickness of patients with normal echocardiography was compared with IM thickness of patients with echocardiographic evidence of IHD. Mean IM thickness of patients with normal echocardiography was 0.9250 ( 0.2863) and IM thickness of patients with echocardiographic evidence of IHD was 1.3455 ( 0.2734) [statistically significant (student's t-test)]. Thus, in our study IM thickness of >1mm could be taken as an indicator for presence of IHD.


   Echocardiographic findings Top


Echocardiography was normal in 20 patients (31.7%) and showed diastolic dysfunction in 13 patients (20.6%), left ventricular hypertrophy in 10 patients (15.9%), left ventricular hypokinesia in 11 cases (17.5%) and rheumatic heart disease in four cases (6.3%). Thus, a potential cardioembolic source was present in 23.8% of cases.

When carotid Doppler and echocardiographic findings were compared it was observed that of 15 patients with potential cardioembolic source 10 (66.7%) had normal carotid arteries. 2 (13.3%) had < 40% stenosis. Another 2 (13.3%) had > 40% stenosis and 1 (6.7%) had complete occlusion. Of patients with > 40% stenosis 2 (50%) had normal echocardiography or diastolic dysfunction and 2 (50%) had left ventricular hypokinesia. Of 2 patients with complete occlusion 1 (50%) had normal echocardiography and 1 (50%) had left ventricular hypokinesia


   Discussion Top


Prevalence of atherosclerosis increases with age [11]. Wolf et al (1991) reported a mean age of 65. 4years in men and 66.1 years in females[12]

Overall men are more prone to atherosclerosis than women. This might be explained on the basis of protective role of the female hormones. After menopause, when this effect wanes, the rates of diseases become similar. [13] Smoking is a recognized significant risk factor [14],[15] Smoking causes a reduction of HDL levels and fibrinogenemia [11] Hypertension produces a continuous trauma to endothelium and predisposes to the early stage of atherogenesis. In advanced atherosclerosis it might contribute to plaque growth [11] In North Trondelag health survey raised systolic and diastolic blood pressures and anti hypertensive treatment were identified as significant risk factors [15] Wolfe et al (1991) using the Framingham study cohort found Mean systolic blood pressure to be 139.3mm Hg in males and 142.8mm Hg in females. [12] Dhamija et al (1998) also concluded hypertension was the most consistent risk factor and systolic blood pressure being more closely related to ischaemic stroke than diastolic pressure[16] Diabetes mellitus is recognized significant risk factor [14],[15] Incidence of stroke in diabetics has been found to be 2 to 3 times higher than in general population [17] Presence of PVD has been associated with presence of carotid atherosclerotic disease [14] March et al (1996) screened 188 patients with claudication out of which 8% had an internal carotid artery stenosis of 16% to 49%, 21.8% had a stenosis that exceeded 50%, and 2.7% had an occluded internal carotid artery. They recommended routine carotid duplex screening to detect asymptomatic high-grade stenosis in patients with PVD. [18] Asymptomatic bruit is recognized as an indication for carotid Doppler evaluation [19]. In North Trondelag health survey prior stroke was identified as a significant risk factor [15] Higher cholesterol levels are associated with higher incidence of carotid atherosclerotic disease [14] There is evidence that high levels of LDL cholesterol predispose to atherosclerosis, while high levels of HDL cholesterol have protective role [20]

In our study the mean age of patients without any carotid lesion was 48.83 ( 15.27) years and mean age of patients with carotid lesion was 60.03 ( 11.29) years. Out of 29 males 18 (62%) had a carotid lesion and out of 34 females only 8 (23%) had a carotid lesion. (p<0.01). None of the premenopausal women in the study had a carotid lesion while around 40% of postmenopausal women had abnormal carotid Doppler. (p<0.05). Presence of hypertension (p<0.01), systolic blood pressure, smoking (p<0.05), diabetes mellitus (p<0.05), history suggestive of peripheral arterial disease (p<0.01), previous CVA (p<0.01) were determined to be statistically significant risk factors. All the patients with a carotid bruit had abnormal carotid Doppler. Mean cholesterol levels in patients with normal carotid arteries was 186.52( 36.88) mg% and mean cholesterol level in patients with carotid lesion was 219.11( 35.13). Obesity, CAD, diastolic blood pressure, blood sugar levels, triglyceride levels were not shown to be statistically significant.

In our study 50% of the plaques were located at the bifurcation, 19.4% in internal carotid and 30.6% in the common carotid artery. This finding is similar to that observed by Rajagopal et al (2000). [21] One twenty six vessels were compared on spectral waveform analysis and color flow imaging. Hypoechoic plaque was missed on B-mode imaging. . In a similar study Erickson et al (1989) found that Color Flow Imaging is superior to B-mode scanning in identification of hypoechoic plaques. [3] 5.5% of plaques showed evidence of ulceration on color flow imaging. Steinke et al (1990) also found significant improvement in identification of ulcerated plaques with Color Flow Imaging over B-mode scanning. [22] Color flow imaging diagnosed two vessels as completely occluded, both of which were assigned same stenosis category by duplex imaging. Erickson et al (1989) and Steinke et al (1990) have calculated the percentage of stenosis by directly measuring the color flow lumen at the site of maximum stenosis and then comparing it with total lumen of vessel itself. [3],[22] But some authors like Polak et al (1989) have used color only as a road map for placement of Doppler sample and thus performing color assisted spectral analysis. They calculated the degree of stenosis using the velocity criteria. In the present study we calculated degree of stenosis by directly measuring residual lumen at the site of maximum stenosis and comparing it with total lumen. At the site of maximal stenosis spectral analysis was done and degree of stenosis estimated using velocity criteria. [23] Robinson et al (1992) found that color imaging is helpful as it improves visualization of the lumen and consequently allows for more accurate placement of the cursor and correction of the Doppler angle. [24]

In our study, the overall perfect agreement between Color Flow Imaging and conventional duplex scanning was 96.8%. These findings were similar to that of Steinke et al (1990) who assessed carotid artery disease in 180 patients by means of color Doppler flow imaging. According to them, the accuracy of color Doppler in classifying stenosis ranged from 91.3-97.8% vs. standard Doppler sonography and 91.7-95.8% vs. angiography. [22] Hallam et al (1989) carried out a double blind comparison of color flow Doppler with conventional duplex scanning in 146 carotid bifurcations in 74 patients. In 91% the color flow assessment was in complete agreement with the duplex assessment. [25] Power Doppler mode Doppler is particularly important for detecting trickle flow in patients with complete occlusion. In both our patients with complete occlusion findings of color flow imaging and spectral analysis were confirmed on power Doppler imaging. No trickle flow was observed. Bluth et al (2000) evaluated power Doppler screening as a possible screening examination for carotid artery stenosis.

Power Doppler imaging showed sensitivity of 70%, specificity of 91%. [26] According to Koga et al (2001)., power Doppler imaging more accurately depicts ICA stenosis by providing better visualization of the stenotic vascular lumen than does the color Doppler flow imaging. [27] The color display on power Doppler images is independent of the angle of insonation, and more importantly, from velocity and direction of moving blood. [28]

IM Thickness Mean IM thickness of patients with normal echocardiography was 0.9250 ( 0.2863) and IM thickness of patients with echocardiographic evidence of IHD was 1.3455 ( 0.2734). Thus, in our study IM thickness of >1mm could be taken as an indicator for presence of IHD. These findings were similar to those by Polak et al (1989) and Jadhav et al (2001) who considered thickening of I-M complex greater than 0.8mm as abnormal and as the earliest changes of atherosclerotic disease.[6],[7]

Echocardiography showed a potential cardioembolic source in 23.8% of cases. These findings are similar to Cerebral embolism task force (1986) results according to which one in six ischaemic strokes is due to cardiogenic embolism. [29] Two-dimensional echocardiography, introduced for clinical use in 1978, has acquired importance in screening patients of cerebrovascular disease [30]. When carotid Doppler and echocardiographic findings were compared it was observed that of 15 patients with potential cardioembolic source two (13.3%) had > 40% stenosis and one (6.7%) had complete occlusion. Of patients with > 40% stenosis two (50%) had left ventricular hypokinesia. Of 2 patients with complete occlusion one (50%) had left ventricular hypokinesia. This observation is similar to De Rook et al (1992) who observed that even in patients with a cerebrovascular or a carotid flow-limiting lesion, a concurrent cardiac lesion may be present and hence such patients should be screened by echocardiography too. [31]


   Conclusion Top


The introduction of Doppler imaging has dramatically changed the diagnostic evaluation of suspected carotid disease. Doppler sonography provides a rapid, non-invasive, relatively inexpensive and accurate means of diagnosing carotid stenosis. Physicians have long sought methods for identifying stroke-prone patients, with the hope that timely intervention might avert stroke and its accompanying disability. The present study highlights the importance of Doppler sonography in this stroke prevention effort through surveillance for atherosclerosis that predisposes a person to cerebral ischaemia.

 
   References Top

1.Coll RE, Will RG. Diseases of nervous system. In Edwards CRW, Bouchier IAD, Haslett C, Chilvers ER (eds) Davidson's Principles and Practice of medicine 1996; 17th edition: 1071-1078.   Back to cited text no. 1    
2.North American Symptomatic Carotid Endarterectomy Trial (NASCET) steering committee- North American Symptomatic Carotid Endarterectomy Trial : methods, patient characterstics and progress. Stroke 1991;22:711.  Back to cited text no. 2    
3.Erikson SJ, Lawson TL, Middleton WD, Quiroz FA, Macrander SJ, Dennisfoley W. Stenosis of internal carotid artery-assessment using color Doppler imaging compared with angiography. AJR 1989; 152: 1299-1305.  Back to cited text no. 3    
4.Ruggieri PM, Masaryk TJ, Ross JS. Magnetic Resonance Angiography - cerebrovascular applications. Stroke 1992; 23(5): 774-780.  Back to cited text no. 4    
5.Summers PE, Jarosz JM, Markus H. MR angiography in cerebrovascular disease. Clinical Radiology 2001; 56: 437-456.   Back to cited text no. 5  [PUBMED]  [FULLTEXT]
6.Polak JF. Carotid ultrasound. RCNA 2001; 39(3): 569-589   Back to cited text no. 6    
7.Jadhav UM, Kadam NN. Carotid Intima-Media thickness as an independent predictor of coronary artery disease. Indian Heart J 2001; 53: 458-462.   Back to cited text no. 7  [PUBMED]  
8.Carroll BA. Carotid ultrasound. Neuroimaging Clinics of North America 1996; 6(4): 875-897.   Back to cited text no. 8    
9.Boiten J, Lodder I. Lacunar infarcts-pathogenesis and validity of clinical syndromes. Stroke. 1991; 22:1374-1378.   Back to cited text no. 9    
10.Tegos TJ, Kalodiki E, Sabetai MM, Nicolaides AN.Stroke- pathogenesis, investigations and prognosis. Angiology. 2000; 51:885-894.  Back to cited text no. 10    
11.Tegos TT, Kalodiki E, Sabetai MM, Nicolaides AN. The genesis of atherosclerosis and risk factors- A review. Angiology. 2001;52(2):89-98.   Back to cited text no. 11    
12.Wolf PA, D'Agostino RB, Bilanger AJ, Hannel WB. Probability of stroke- A risk profile from the Framingham heart study. Stroke. 1991; 22:312-318.   Back to cited text no. 12    
13.Finucana FF, Madans JH,Bush T.L., Wolf PH, Kleinman JC. Decreased risk of stroke among post menopausal hormone users. Arch Inter Med.1993;153:73-79.   Back to cited text no. 13    
14.Duncan GW, Slees R, Ojemann RG, David SS. Concominants of atherosclerotic carotid artery stenosis. Stroke. 1977;8(6): 665-668.   Back to cited text no. 14    
15.Ellekjaer EP, Wyller TB, Sverve JM, Holmen J. Life style factors and risk of cerebral infarction.Stroke. 1992; 23(6): 829-834   Back to cited text no. 15    
16.Dhamija RK, Dhamija SB. Prevalence of stroke in the rural community-An overview of Indian expeience. JAPI 1998; 46(4): 351-354.   Back to cited text no. 16    
17.Kistler JP, Roppert AH, Martin JB. Cerebrovascular disease. In Harrisons principles of internal medicine 1994; 13th edition: 2233-2256.   Back to cited text no. 17    
18.March J, Millis JC, Harvich J, Cul H, Fujitani RM. Utility of routine carotid duplex screening in patients who have claudication. J Vasc Surg 1996; 24: 572-579.   Back to cited text no. 18    
19.Zwiebel WJ. A primer of cerebrovascular ultrasound. Seminars in US, CT and MR 1987; 8(1): 2-57.   Back to cited text no. 19    
20.Tell GS, Philos, Crouse JR, Furberg GD. Relation between blood lipids, lipoproteins, and cerebrovascular atherosclerosis-A review. Stroke.1988;19:423-430   Back to cited text no. 20    
21.Rajagopal KV, Lakhkar BN, Banavali S, Singh NK. Pictorial essay- color duplex evaluation of carotid occlusive lesions. Ind J Radiol Imag 2000; 10: 4.   Back to cited text no. 21    
22.Steinke W, Kloetzch C, Hennirici M. Carotid artery disease assessed by color Doppler flow imaging- correlation with standard Doppler sonography and angiography. AJNR 1990; 11(4): 259-266.   Back to cited text no. 22    
23.Polak JF, Dobhin GR, O'Leary DH, Cutler SS. Internal carotid artery stenosis-accuracy and reproducibility of color Doppler assisted duplex imaging. Radiology 1989; 173: 793-798   Back to cited text no. 23    
24.Robinson ML, Sachs D, Perimutter GS, Marinelli DL. Diagnostic criteria for carotid duplex sonography. AJR 1988; 151(11): 1045-1049.   Back to cited text no. 24    
25.Hallam MJ, Reid JM, Cooperberg PL. color flow Doppler and conventional duplex scanning of the carotid bifurcation-prospective, double blind, correlative study. AJR 1989;152(5): 1101-1105   Back to cited text no. 25    
26.Bluth EJ, Sunshine JH, Lyons JB, Beam CA, Crawson PE. Sullivan M.A., Neiman H.L. Power Doppler imaging-initial evaluation as a screening examination for carotid artery stenosis. Radiology 2000; 215: 791-800.   Back to cited text no. 26    
27.Koga M, Kazumi K, Minamatsu K, Yamaguchi T. Diagnosis of ICA stenosis greater than 70% with power Doppler duplex sonography. AJNR Am J Neurolradiol 2001; 22: 413-417.   Back to cited text no. 27    
28.Chaubal NG. Basics of Doppler. Ind J Radiol Imag 1998; 8(1): 1-7.   Back to cited text no. 28    
29.Cardiogenic brain embolism- cerebral embolism task force. Arch neurol 1986; 43: 71-84.   Back to cited text no. 29    
30.Ram JA, Hachiniski VC, Boughner DP, Barnett HJM. Value of cardiac monitoring and echocardiography in TIA and stroke patients. Stroke 1985; 16(6): 950-955.   Back to cited text no. 30    
31.DeeRook FA, Comess KA, Albers GW, Papp RL. Transesophageal echocardiography in evaluation of stroke. Ann Intern Med 1992; 177(11): 922-933.  Back to cited text no. 31    

Top
Correspondence Address:
S K Sethi
C P-109, Pitampura, Maurya Enclave, Delhi-110088
India
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0971-3026.28756

Rights and Permissions


    Figures

[Figure - 1], [Figure - 2], [Figure - 3], [Figure - 4], [Figure - 5], [Figure - 6], [Figure - 7], [Figure - 8], [Figure - 9], [Figure - 10]

    Tables

[Table - 1], [Table - 2], [Table - 3], [Table - 4], [Table - 5]

This article has been cited by
1 Frequency of internal carotid artery stenosis in patients with cerebral infarct
Ram Devrajani, B. and Kadir, S.M. and Ur Rahman, A.A. and Ahmed Junejo, M. and Junejo, H. and Qutrio Baloch, Z.A.
World Applied Sciences Journal. 2013; 23(1): 24-28
[Pubmed]
2 Multi imaging approach with low field MRA in diabetic foot ulcer: hospital based study
Amit Nandan Dhar Dwivedi, K. K. Tripathi, R. C. Shukla
International Journal of Diabetes in Developing Countries. 2011;
[VIEW] | [DOI]
3 Frequency, characteristics and risk factors of Carotid Artery Stenosis in ischaemic stroke patients at Civil Hospital Karachi
Shaikh, N.A., Bhatty, S., Irfan, M., Khatri, G., Vaswani, A.S., Jakhrani, N.
Journal of the Pakistan Medical Association. 2010; 60(1): 8-12
[Pubmed]



 

Top
 
  Search
 
    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
    Email Alert *
    Add to My List *
* Registration required (free)  


    Abstract
    Introduction
    Material and methods
    Results
    Age distribution
    Plaque character...
    Ulceration
    Plaque location
    Color flow imagi...
    Power doppler im...
    IM THICKNESS- AN...
    Echocardiographi...
    Discussion
    Conclusion
    Doppler technique
    Visual inspectio...
    References
    Article Figures
    Article Tables

 Article Access Statistics
    Viewed10071    
    Printed201    
    Emailed4    
    PDF Downloaded900    
    Comments [Add]    
    Cited by others 3    

Recommend this journal